News: Centre: Physics Centre related to Chalmers University of TechnologyTue, 24 Nov 2020 13:29:20 +0100öran wants to build Sweden&#39;s first quantum computer<p><b>​Physicist, researcher and TedX speaker. It is important to Göran Johansson to talk to others about his research. He is also one of the driving forces behind the construction of Sweden&#39;s first quantum computer. “The dream is to be able to solve a real problem with a quantum computer,” he says.​​</b></p><div><span style="background-color:initial">Quantum physics has followed Göran Johansson like a golden thread throughout his academic career. He is Professor of Applied Quantum Physics and Head of the Applied Quantum Physics Laboratory (AQP) at the Department of Microtechnology and Nanoscience, MC2, at Chalmers. </span><br /></div> <div>“Traditional mechanics felt comprehensible, but I didn’t feel the same about quantum physics. I thought it was strange. Which is why I have spent much of my life thinking about quantum physics in various contexts,” he says. </div> <div><br /></div> <div><img src="/SiteCollectionImages/Institutioner/MC2/News/gjohansson_300x450_listbild_artikelbild.jpg" class="chalmersPosition-FloatRight" alt="Picture of G Johansson" style="margin:5px" />Göran divides his time between a number of activities. As well as being Head of AQP, he is Deputy Head of the Excellence Initiative Nano (EI Nano), and one of the principal researchers in the billion SEK project the Wallenberg Centre for Quantum Technology (WACQT), the aim of which is to build a functioning quantum computer within twelve years. </div> <div>“We want to find the real problems that are best suited to a quantum computer. It would be fascinating to be able to use quantum physics to solve difficult problems like flying more efficiently, perhaps with fewer planes and fewer flights. We want to see whether a quantum computer can do the job better and we’ve carried out an initial theoretical calculation that shows that it works,” says Göran.</div> <div><br /></div> <div>WACQT has initiated partnerships with a number of companies such as Jeppesen and Volvo. Göran Wendin is the driving force behind a partnership with Astra Zeneca which may eventually lead to new medicines. Another project is in progress with researchers at Sahlgrenska University Hospital and concerns calculations for DNA sequencing.</div> <div>“These are all extremely difficult calculation problems with which a quantum computer could help,” explains Göran Johansson.</div> <div>At WACQT he also manages a graduate school with around thirty doctoral students.</div> <div><strong>How do you manage everything?</strong></div> <div>“Well, I don’t really. WACQT is a huge project in which I coordinate the theoretical work. And the core of operations is now up and running with a number of excellent corporate partnerships,” says Göran. </div> <div>What do you enjoy most?</div> <div>“Thinking about problems, discussing physics and supervising doctoral students. But just sitting on my own doing calculations can be a bit boring.”</div> <div><br /></div> <div>We meet at the cosy Kafé Zenith in the Majorna district of Gothenburg. This is Göran’s home turf. He has spent a lot of time here. He knows the district like the back of his hand.</div> <div>“I thought it would be fun to meet in Majorna. My parents grew up in Majorna and we used to visit my grandparents here when I was small. When I left home, I moved to Klarebergsgatan street and lived there until we moved to Kommendörsgatan street, which is just 100 metres from here.”</div> <div>Part of what he loves about the area is its rich and varied cultural life.</div> <div>“Yes, there is much to enjoy here. I used to listen to new music and buy LPs at Bengans a stone’s throw from here.”</div> <div><br /></div> <div>Göran Johansson grew up in Påvelund, where his parents moved from the Frölunda Torg area. His mother was a domestic science teacher and his father a mechanical engineer who studied at Chalmers. Göran also has a sister who is four years older. He now lives with his wife Annika and their two children Adam, who is studying engineering physics at Chalmers, and Ellen, who is in the first year of upper secondary school, in a terraced house in Hagen, very close to Påvelund.</div> <div>“As you can see, I haven’t moved very far,” he says with a smile. </div> <div><br /></div> <div>Göran developed an interest in technology at a young age. There is still something of the technical dreamer from his childhood in Påvelund in the 70s and 80s about Göran Johansson. He lights up when he talks about exploring science as a child, often with his father.</div> <div>“He has always been interested in technology. I used to get up early and go with him to his shed. He would bring home old electronic gadgets, and he let me cut off all the resistors and sort them. We watched popular science TV shows. I really liked Carl Sagan’s TV series ‘Cosmos’ and learned a lot from it. Above all, I was extremely interested in physics and wanted to understand how the world works. I have always wanted to find new things,” says Göran.</div> <div><br /></div> <div>He was also a member of the ‘Teknoteket’ technology club started by Staffan Ling and Bengt Andersson, the duo behind the children’s TV programme ‘Sant &amp; Sånt’.</div> <div>“You got a box of puzzles and books with a technology theme through the post every month. There were boxes on nuclear power, on genetic engineering and much more besides,” says Göran.</div> <div><br /></div> <div>He decided to take one of the first classic home computers along to the photo session at Henrik Sandsjö’s studio in Röda Sten, a Sinclair ZX81. It turns out to be the very machine that Göran bought aged eleven in London in 1981 on a trip with his family.</div> <div>“It was my first computer, and I’ve kept it all these years. It was on sale for half price in London! The next day I wanted to buy a game. At that time, you bought games on cassette tapes and I remember getting to the shop at closing time, putting my foot in the door and saying in my broken English “I want to buy a computer game”. They let me in to buy one,” he says. </div> <div>Göran gets enthusiastic:</div> <div>“Back then, you could buy magazines with program code for games that you could program yourself. When I connected the computer up at home, I suddenly realised that you could write on TV! It was a great feeling.”</div> <div>As a childhood memory, there is still a big sticker from ‘Teknoteket’ on the computer, a collage of stars, planets and Albert Einstein.</div> <div><br /></div> <div>After taking the natural sciences course at school at Sigrid Rudebecks Gymnasium, Göran began studying engineering physics at Chalmers.</div> <div>“I knew that I wanted to do that at a very early stage. I think it’s because my dad studied mechanical engineering at Chalmers. He was the first in his family to go to university. I remember him saying that “the engineering physics students really seem to know what they are talking about...”.”</div> <div><br /></div> <div>His studies at Chalmers were interrupted after six months by 15 months’ military service in Sollefteå, but in February 1995 Göran graduated as an engineer. He was 23 years old and he wanted more.</div> <div>“I did some extra work on theoretical physics with Professor Bengt Lundqvist while I was studying and spent some time with the doctoral students. I didn’t really think that I learned all that much as an undergraduate and wanted to learn more. So it was quite natural to continue,” says Göran. </div> <div>This involved postgraduate studies with professors Göran Wendin and Vitaly Shumeiko as supervisors. They are now colleagues at MC2. Göran Johansson wrote his doctoral thesis in 1998: ‘Multiple Andreev Reflection – a Microscopic Theory of ac Josephson Effect in Mesoscopic Junctions’.</div> <div>“In the thesis, we gave a theoretical description of how current flows in a small superconductor. I thought we had discovered something new and was slightly disappointed when our theory was subsequently not used in experiments by other researchers. We had worked hard but no one really cared.”</div> <div><br /></div> <div>His doctoral studies went fast and Göran then spent a few years in the late 90s as a research project manager at Ericsson Mobile Data Design.</div> <div>“I managed a research project on computer communication. It was about digital radio, and we were looking at how you could download data extremely fast on your mobile using the digital radio network,” he explains.</div> <div><br /></div> <div>However, his longing to do proper research again grew, and when Göran Wendin offered him the opportunity to be part of an EU project, he returned to Chalmers. </div> <div>“At Ericsson, I realised that I like solving mathematical problems. I now had the chance to be involved in a project with the aim of building a superconducting quantum computer that was actually based on the technology in my thesis. Now it was OK to do calculations with our small superconductors.”</div> <div><br /></div> <div>Göran then became a postdoc at the illustrious Karlsruhe Institute of Technology in Germany, where his family lived in 2002–2004. This was because the Institute was involved in the EU project. Göran thinks with hindsight that the working climate in Germany was quite tough.</div> <div>“It was also extremely exciting to carry on working with superconducting quantum computers, and my wife really liked it there. But when I was offered a position as Assistant Professor at Chalmers in 2004, we returned to Gothenburg.” </div> <div><br /></div> <div>One aim of Göran Johansson’s research is to understand more about how quantum physics works and how its effects can be used in technological applications. He sees great value in presenting research to the general public, and appears as often as he can in various popular science contexts. He has given two TedX talks, in Gothenburg in 2017 and in Lund in 2018.</div> <div>“It is a challenge to explain something so difficult as easily as possible, and it was extremely useful to try and say something interesting in eight minutes... Great fun and slightly nerve-wracking,” he says.</div> <div><br /></div> <div>At Senioruniversitetet i Stockholm, which offers courses for pensioners aged 55 and over, he lectured about quantum computers to 300 people in a full cinema. And this year, he talked about the future on an expert panel at a science fiction festival. </div> <div>He knows that his research field is one of the most difficult and most challenging to explain. This is one of the things he has noticed in social situations:</div> <div>“People understand what I am talking about when it’s about computer communication and mobile surfing. As soon as I mention quantum physics, which I think is fun and in which I have a PhD, people stop listening,” he laughs. </div> <div><br /></div> <div>2020 saw the publication of the book ‘Kvantfysiken och livet’ (Quantum Physics and Life) (Volante Förlag), which Göran wrote with Göran Wendin, Joar Svanvik, Ingemar Ernberg and the science journalist Tomas Lindblad. This interdisciplinary book shows how a combination of quantum physics and medical research may form the basis of the next scientific revolution. It took several years to write.</div> <div>“First, we read papers and discussed among ourselves for a number of years. Then we each wrote a few chapters, which we then read and commented on. When Tomas entered the picture, he looked through all the chapters and made the style a little more consistent. It was a lot of work, but so great when it was finished. We are also talking about an English version,” says Göran.</div> <div>Most of the marketing activities have been postponed on account of the coronavirus pandemic. However, there is a piece on UR Play in which co-author Ingemar Ernberg is interviewed about the book by Tomas Lindblad. There are also plans to take part in the Aha festival at Chalmers in May 2021. Göran is on the festival organising committee.</div> <div><br /></div> <div>In 2012, Göran Johansson was involved in a major innovation. Researchers at Chalmers had succeeded in creating light from a vacuum, a milestone in quantum mechanics that physicists had been anticipating for over 40 years. With the experimentalists Per Delsing and Christopher Wilson, Göran was able to demonstrate the dynamic Casimir effect.</div> <div>“It is an example of an interesting fundamental effect of quantum mechanics which describes how photons are generated from a vacuum when a mirror accelerates and moves at speeds close to the speed of light,” he explains.</div> <div>The researchers’ article was published in the journal Nature and attracted huge attention from Swedish and international media. The experiment was based on Göran’s theories, and they were able to capture photons that constantly emerge and disappear in a vacuum. The media described the discovery as ‘creating light from a vacuum’.</div> <div>“It was the most enjoyable project I have worked on and I got a real kick out of it. It was the first time I was involved in such a high-profile project. If you are published in Nature, doors open and you have the chance to be interviewed on Vetenskapsradion (a science programme on Swedish radio) and in other media. It means a lot and is a career boost,” says Göran.</div> <div><br /></div> <div>Not long afterwards, he was awarded two prestigious prizes: the Albert Wallin Science Prize by the Royal Society of Arts and Sciences in Gothenburg, and the Edlund Prize by the Royal Swedish Academy of Sciences.</div> <div>“I was really happy. The Albert Wallin prize was my first prize, so of course it means a little more.”</div> <div><strong>I assume that you sometimes have some free time. What do you like doing?</strong></div> <div>“I am trying to be better at taking time off and switching off properly. I like family dinners and being out in nature,” he says.</div> <div>Running is another interest, and Göran has run the Göteborgsvarvet half marathon many times.</div> <div>“The first time I was still at school and I was unable to finish. That taught me that you have to have good shoes.”</div> <div>The Lidingöloppet cross country race, the Kiel Marathon and the Skogsmaran run between Skatås and Hindås along the Vildmarksleden trail are other competitions he has taken part in.</div> <div>“I like running a long way but not very fast,” he says with a smile.</div> <div><br /></div> <div>Science fiction is one of Göran’s major interests, both literature and films. </div> <div>“This is one of my favourite film and literary genres. When I was small, I read every single science fiction book I could find in the library.”</div> <div>His favourites include Jules Verne and Isaac Asimov, in particular the latter’s Foundation trilogy and ‘I, Robot’. </div> <div>“Jules Verne was extremely prescient. And I’ve read all of Haruki Murakami! ‘The Wind-Up Bird Chronicle’ was the first of his I read. There is another that is a mixture of a hard-boiled detective novel and fantasy – ‘Hard-Boiled Wonderland and the End of the World’.” </div> <div><br /></div> <div>He also recommends films such as ‘The Fifth Element’, ‘The Matrix’, ‘Interstellar’, ‘Star Wars’ and ‘Star Trek’. </div> <div>“The first Matrix film is still good. I watched it in the cinema with my daughter on its 20th anniversary. She liked it as well.”</div> <div>Göran has also been a guest reviewer of the TV series ‘Devs’ on the website of publisher Volante. A quantum computer plays an important role in the series.</div> <div>“It’s a nice thriller with good music that deals with quantum physics in a relevant, well-informed and appealing manner,” he says.</div> <div><br /></div> <div>Given that he used to hang out at Bengans record shop, it is hardly surprising that Göran also loves music. When he was younger, he listened to a lot of synth. Depeche Mode, Lustans Lakejer and Ultravox were some of his idols. Later, his taste broadened to include Talking Heads, Kent and Olle Ljungström.</div> <div>“I saw an early recording with Broder Daniel of the Swedish TV show Valvet as a friend’s brother was in the band. ‘Shoreline’ is one of my favourite songs, by both Broder Daniel and Anna Ternheim.”</div> <div>Håkan Hellström is a big favourite with the entire family.</div> <div>“We listen to him all the time and had tickets for concerts in both June and August, but unfortunately they were postponed to 2021.”</div> <div><br /></div> <div>At the end of the year, Göran Johansson will leave his position at EI Nano, which will then come under new leadership. The plan is to take his family to MIT in Boston towards summer 2021 and live there as a guest researcher for a year. </div> <div><br /></div> <div>Text: Michael Nystås</div> <div>Photo: Henrik Sandsjö</div> <div>Photo of Göran drinking coffee: Michael Nystås</div> <div><br /></div> <div><span style="background-color:initial"><a href="">See Göran Johansson at TedX Lund on 14 November 2018</a> &gt;&gt;&gt;</span><span style="background-color:initial"> </span></div> <div><br /></div> <div><a href="">See the piece on the book ‘Kvantfysiken och livet’ on UR Play</a> &gt;&gt;&gt;</div> <div><br /></div> <div>Read more about the high-profile Nature article &gt;&gt;&gt;</div> <div><a href="">Chalmers researchers create light from a vacuum</a></div> <div><br /></div> <div><a href="">Read Göran’s review of the TV series ‘Devs’</a> &gt;&gt;&gt;<span style="background-color:initial"> </span></div> <div><br /></div> <div><a href="">Read more about the Sinclair ZX81 home computer</a> &gt;&gt;&gt;</div> <div><span style="color:rgb(33, 33, 33);font-family:inherit;font-size:16px;font-weight:600;background-color:initial"><br /></span></div> <div><span style="color:rgb(33, 33, 33);font-family:inherit;font-size:16px;font-weight:600;background-color:initial">ABOUT GÖRAN</span><br /></div> <div><strong>Born:</strong> Yes, 7 December 1971 in Påvelund.</div> <div><strong>Lives:</strong> Terraced house in Hagen, Gothenburg.</div> <div><strong>Family:</strong> Wife and two children.</div> <div><strong>Job:</strong> Professor of Applied Quantum Physics at Chalmers.</div> <div><strong>Career in brief:</strong> Has been trying to build a quantum computer since 2000.</div> <div><strong>Leisure interests:</strong> Running and forest walks. Family, music, film and books.</div> <div><strong>Favourite place for inspiration:</strong> Out in the forest. I switch off and am happy.</div> <div><strong>Most proud of:</strong> My children. I am pleased that they seem to enjoy life. In terms of research, the experiment on the dynamic Casimir effect.</div> <div><strong>Motivation:</strong> Curiosity.</div> <div><strong>Best thing about being a researcher:</strong> Being curious, exploring new things, thinking about how the world works and finding new solutions. I think that is really exciting.</div> <div><strong>Challenges of the job:</strong> Being innovative and asking the right questions that can be answered. I now have a role in which I also have to inspire others and get them to work well with each other. This is always a challenge. Everyone is motivated by different things. As with all jobs, it is easier if you like what you do. I try to help people feel that way.</div> <div><strong>Dream for the future:</strong> One dream is to find a problem that a quantum computer can solve. That would be fantastic. I look forward to spending a year at MIT. Otherwise I am very happy with my lot and think that I have found the right balance between administration and research. No radical changes are needed in my life. Maybe just to find a new dream in the future.</div> Tue, 24 Nov 2020 09:00:00 +0100 to the Information and Communication Technology of the future<p><b>​Anders Larsson and Jan Stake at MC2 are two of the Chalmers researchers who receive funding from the Swedish Foundation for Strategic Research (SSF). &quot;We will now, for the first time, be able to channel monitoring and adaptivity of signal parameters in real time to sustain the highest possible interconnect data throughput over temperature,&quot; says Anders Larsson, professor of photonics.</b></p>SSF distributes close to SEK 200 million to six different projects in a research effort for faster and energy-efficient Information and Communication Technology (ICT). The six projects are financed with between SEK 28 and 35 million each for five years, starting 2021.<br />&quot;Together, they have the potential to strengthen Sweden’s position in important areas for our industry and competitiveness,&quot; says Jonas Bjarne, research secretary at SSF, in a press release.<br /><br /><img src="/SiteCollectionImages/Institutioner/MC2/News/anders_larsson_170112_350x305.jpg" alt="Picture of Anders Larsson." class="chalmersPosition-FloatRight" style="margin:5px" />Anders Larsson (to the right), professor at the Photonics Laboratory at the Department of Microtechnology and Nanoscience – MC2, is granted SEK 32 253 449 for the project &quot;Optical interconnects for harsh computing environments&quot;, which is about enabling more powerful computers and computing systems.<br />Larsson explains that optical interconnects are increasingly used to provide the interconnect bandwidth, bandwidth density, and energy efficiency needed in high-performance computing systems, whether being a large-scale datacenter or a single high-capacity signal processing unit. Future optical interconnects for datacenters, automotive networks, and advanced radar systems will require operation under more harsh conditions, at much higher temperatures and over a much larger temperature range. <br />&quot;This is a considerable challenge and calls for the development of a new generation high-temperature optoelectronic components and electronic ICs, more tolerant to temperature variations, and for exploring adaptivity to compensate for large variations of the optical channel response,&quot; says Anders Larsson.<br /><br />The project will enable this by bringing together leading expertise in optoelectronics, electronics, and optical communication. It involves four research groups at Chalmers led by Anders Larsson, Peter Andrekson, both at MC2, Lars Svensson at the Department of Computer Science and Engineering, and Henk Wymeersch at the Department of Electrical Engineering. <br />&quot;We will develop a new generation high-temperature lasers and driver/receiver ICs, tolerant to temperature variations, and explore, for the first time, channel monitoring and adaptivity of signal parameters in real time to sustain the highest possible interconnect data throughput over temperature,&quot; explains Anders Larsson.<br /><br />The project also involves close collaboration with Nvidia, Volvo Cars, and Saab Surveillance, companies in Göteborg dependent on this technology for future products in their markets: datacenters, vehicles, and radars.<br /><br /><img src="/SiteCollectionImages/Institutioner/MC2/News/jan_stake_I0A6537_350x305.jpg" alt="Picture of Jan Stake." class="chalmersPosition-FloatLeft" style="margin:5px" />Jan Stake (to the left), professor of Terahertz Technology and head of the Terahertz and Millimetre Wave Laboratory at the Department of Microtechnology and Nanoscience – MC2, is co-applicant in a project led by Joachim Oberhammer at KTH Royal Institute of Technology. <br />&quot;In the project, we want to demonstrate telecommunications at frequencies close to 1 THz, which has not been done before in Sweden. Achieving the goal requires new combinations of different technologies, and we collaborate with expertise at Chalmers, where they have developed some of the most prominent semiconductor devices for THz frequencies,&quot; says Joachim Oberhammer in an article on KTH's website.<br /><br />Jonas Bjarne, research secretary at SSF, underlines that four of the six proposed projects have the theme of energy efficiency in common. <br />&quot;This is strategically very important as the ICT sector’s dramatically increasing energy consumption is receiving increasing attention,&quot;, he says.<br /><br />Besides Larsson and Stake, Per Stenström, professor at the Computer Engineering division at the Department of Computer Science and Engineering, is granted SEK 28 086 883 in the same announcement.<br /><div><br /></div> Photo of Anders Larsson: Henrik Sandsjö<br />Photo of Jan Stake: Anna-Lena Lundqvist<br /><br /><a href="">Read press release from SSF &gt;&gt;&gt;</a><br /><br /><a href="/en/departments/cse/news/Pages/principles-for-computing-memory-devices.aspx">Read news article about Per Stenström's project &gt;&gt;&gt;</a><br /><br /><a href="">Read news article about the KTH/Chalmers project &quot;THz kommunikation – NU&quot; (in Swedish) &gt;&gt;&gt;</a>Thu, 05 Nov 2020 09:00:00 +0100–spin-dynamics-studied-on-their-natural-timescale.aspx–spin dynamics studied on their natural timescale<p><b>​With the help of extremely short light pulses and coincidence technology, researchers from several Swedish universities have succeeded in following the dynamic process of when the electron&#39;s spin – its rotation around its own axis – controls how an atom absorbs light. Göran Wendin, at the Department of Microtechnology and Nanoscience – MC2, at Chalmers and Raimund Feifel, at the Department of Physics at the University of Gothenburg, are two of the contributors. The new results were recently published in the scientific journal Nature Communications.</b></p><div><img src="/SiteCollectionImages/Institutioner/MC2/News/GoranWendin_171101_01_350x305.jpg" class="chalmersPosition-FloatRight" alt="Picture of Göran Wendin." style="margin:5px" />Professor Göran Wendin (to the right) is one of the driving forces within the Wallenberg Centre for Quantum Technology (WACQT), which is led by Chalmers and aims to build a Swedish quantum computer within twelve years. He is involved in several research projects, including this, financed by Knut and Alice Wallenberg Foundation (KAW).</div> <div>&quot;In fact, my contribution goes all the way back to my doctoral thesis from 1972 which explained the photo absorption cross section of the 4d-shell in xenon in the range 70-140 eV, studied by the present KAW collaboration,&quot; explains Göran Wendin.</div> <div> </div> <div>In the new study, the researchers have used attosecond light pulses and coincidence techniques to follow – in real time – how the electron spin (i.e. the angular momentum of the electron around its own axis) influences the absorption of a photon in a  many-electron quantum system, the xenon atom. An attosecond is a billionth of a billionth of a second.</div> <div> </div> <div>The study is using xenon, a heavy rare gas element that exists in small amounts in the atmosphere of the Earth. It is known to absorb soft x-rays of specific wavelength unusually efficiently. </div> <div>Physicists have named the effect a giant resonance and explained that it is caused by a strong collective response of the electron cloud when the atom is exposed to the x-rays. Especially intriguing is that the electron spin has a pronounced effect on the light absorption in this system.</div> <div> </div> <div>The present analysis combines precision in both time and energy to show that the strong absorption is explained by an excited state living less than 50 attoseconds. The influence of the electron spin, however, is due to a ten times longer-lived nearby state, which can be reached by a change of electron spin (called spin flip). </div> <div>The spin-flipped state serves as a switch and determines the state of the remaining ion. The results provide new insight into the complex electron-spin dynamics of photo-induced phenomena and might be of considerable interest to applied science such as spintronics.</div> <div> </div> <div>Photo of Göran Wendin: Johan Bodell</div> <div> </div> <h3 class="chalmersElement-H3">Read the article in Nature Communications &gt;&gt;&gt; </h3> <div><a href="" target="_blank"> </a></div> <div> </div> <h3 class="chalmersElement-H3">More information &gt;&gt;&gt;</h3> <div>Anne L’Huillier, Department of Physics, Division of Atomics Physics, The Lund Attosecond Science Center (LASC), Lund University, 0705-317529,</div> <div>Eva Lindroth, Department of Physics, Stockholm University, 0736-795034,</div> <div>Göran Wendin, Quantum Technology Laboratory, Wallenberg Centre for Quantum Technology (WACQT), Department of Microtechnology and Nanoscience – MC2, Chalmers, 031-7723189,</div> <div>Raimund Feifel, Department of Physics, University of Gothenburg, 0708-381689,</div> <h3 class="chalmersElement-H3">More background &gt;&gt;&gt;</h3> <div>Inspired by his supervisor, legendary Chalmers Professor Stig Lundqvist (1925-2000), Göran Wendin in his thesis applied the many-body theories developed for collective excitations in atomic nuclei to the electron dynamics in heavy atoms. The point was that independent-electron models did not work – it was all pretty collective, and it explained the experimental data from the pioneering work with synchrotron radiation. Actually, Wendin was the one who in 1973 introduced the name &quot;giant dipole resonance&quot; to describe the phenomenon. </div> <div> </div> <div>While working in France 1981-83, Göran Wendin came in contact with Anne L’Huillier at the research institute Commissariat à l’Energie Atomique (CEA) in Saclay, France. Anne was doing her PhD work in the pioneering high-intensity laser group, and she wanted to do calculations for multiphoton ionization of rare-gas atoms, including xenon. Wendin became her theory supervisor, and they collaborated during the following 5 years and published a number of papers together. </div> <div> </div> <div>After that, Anne L’Huillier took off and became one of the world-leading experimentalists in the field, and she became deeply involved in the development to understand and make use of high-harmonic radiation for attosecond spectroscopy. The Nobel Prize for this kind of work was awarded to Gérard Mourou and Donna Strickland in 2018. </div> <div><br /><a href="/en/centres/gpc/activities/lisemeitner"><span>Professor Anne L’Huillier is also honored with the Gothenburg Lise Meitner Award 2020, which is awarded to scientists who made breakthrough discoveries in p​</span>hysics.​</a><br /></div> <div><br /></div> <div>If one sends intense infrared femtosecond laser pulses on a metal substrate, one can generate a comb of up to 100 overtones with 2 eV distance, covering a range of 200 eV, including the region of the xenon giant resonance. With these experiments one has a stopwatch ticking with attosecond resolution, meaning that one can follow electrons on their flight out of the atom.</div> <div> </div> <div>Related work that Göran Wendin did around 1975-85 had analyzed the giant resonance in term of atomic effective potentials, and that turned out to be very useful when relating the theoretical calculations of Eva Lindroth and her group at Stockholm University to experiment. The good old models for collective excitations – &quot;atomic plasmons&quot; – still provide the background for understanding the results of modern attacks on the atoms with optical and free-electron lasers.</div>Wed, 04 Nov 2020 09:00:00 +0100 importance of good neighbours in catalysis<p><b>Are you affected by your neighbours? So are nanoparticles in catalysts. New research from Chalmers, published in the journals Science Advances and Nature Communications, reveals how the nearest neighbours determine how well nanoparticles work in a catalyst.​​​</b></p><span style="background-color:initial"><img src="/SiteCollectionImages/Institutioner/F/Blandade%20dimensioner%20inne%20i%20artikel/400_ChristophLanghammerfarg.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;height:197px;width:150px" /></span><span style="background-color:initial"></span><span style="background-color:initial">“T</span><span style="background-color:initial">he long-term goal of the research is to be able to identify ‘super-particles’, to contribute to more efficient catalysts in the future. To utilise the resources better than today, we also want as many particles as possible to be actively participating in the catalytic reaction at the same time,” says research leader Christoph Langhammer at the Department of Physics at Chalmers University of Technology.</span><span style="background-color:initial"><br /><br /></span><div>Imagine a large group of neighbours gathered together to clean a communal courtyard. They set about their work, each contributing to the group effort. The only problem is that not everyone is equally active. While some work hard and efficiently, others stroll around, chatting and drinking coffee. If you only looked at the end result, it would be difficult to know who worked the most, and who simply relaxed. To determine that, you w​ould need to monitor each person throughout the day. The same applies to the activity of metallic nanoparticles in a catalyst. <br /></div> <div><span style="background-color:initial"></span></div> <div> <h2 class="chalmersElement-H2"><span>The possibility to study which particle</span><span>s do what, and when</span></h2></div> <div><div>Inside a catalyst several particles affect how effective the reactions are. Some of the particles in the crowd are effective, while others are inactive. But the particles are often hidden within different ‘pores’, much like in a sponge, and are therefore difficult to study.</div> <div>To be able to see what is really happening inside a catalyst pore, the researchers from Chalmers University of Technology isolated a handful of copper particles in a transparent glass nanotube. When several are gathered together in the small gas-filled pipe, it becomes possible to study which particles do what, and when, in real conditions.</div> <div>​<br /></div></div> <div></div> <div><div>What happens in the tube is that the particles come into contact with an inflowing gas mixture of oxygen and carbon monoxide. When these substances react with each other on the surface of the copper particles, carbon dioxide is formed. It is the same reaction that happens when exhaust gases are purified in a car’s catalytic converter, except there particles of platinum, palladium and rhodium are often used to break down toxic carbon monoxide, instead of copper. But these metals are expensive and scarce, so researchers are looking for more resource-efficient alternatives.</div> <br /></div> <div><span style="font-family:bitter, serif;font-size:18px;background-color:initial"><img src="/SiteCollectionImages/Institutioner/F/Blandade%20dimensioner%20inne%20i%20artikel/400_DavidAlbinsson.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;width:150px;height:197px" /></span><span style="background-color:initial">“Copper can be an interesting candidate for oxidising carbon monoxide. The challenge is that copper has a tendency to change itself during the reaction, and we need to be able to measure what oxidation state a copper particle has when it is most active inside the catalyst. With our nanoreactor, which mimics a pore inside a real catalyst, this will now be possible,” says David Albinsson, Postdoctoral researcher at the Department of Physics at Chalmers and first author of two scientific articles recently published in Science Advances and Nature Communications.</span></div> <div><span></span><h2 class="chalmersElement-H2" style="font-family:&quot;open sans&quot;, sans-serif">Optimised neighbourly cooperation can save resources<span style="background-color:initial;font-size:14px">​​ ​</span></h2> <span style="background-color:initial"></span></div> <div><span style="background-color:initial">​Anyon</span><span style="background-color:initial">e who has seen an old copper rooftop or statue will recognise how the reddish-brown metal soon turns green after contact with the air and pollutants. A similar thing happens with the copper particles in the catalysts. It is therefore important to get them to work together in an effective way.​</span></div> <div><br /></div> <div><span style="background-color:initial">“What we have shown now is that the oxidation state of a particle can be dynamically affected by its nearest neighbours during the reaction. The hope therefore is that eventually we can save resources with the help of optimised neighbourly cooperation in a catalyst,” says Christoph Langhammer, Professor at the Department of Physics at Chalmers.<br /></span> <br /></div> <div><b>Text:</b> Mia Halleröd Palmgren and Joshua Worth</div> <div><b>Portrait pictures: </b>Henrik Sandsjö (Christoph Langhammer) Helén Rosenfeldt (David Albinsson)</div> <div><strong>Illustrations:</strong> David Albinsson</div> <div><div><br /><h2 class="chalmersElement-H2" style="font-family:&quot;open sans&quot;, sans-serif">More on the scientific publications​: </h2> <div><ul><li>The article <a href="">Operando detection of single nanoparticle activity dynamics inside a model pore catalyst material​</a> is written by David Albinsson, Stephan Bartling, Sara Nilsson, Henrik Ström, Joachim Fritzsche and Christoph Langhammer, and has been published in the scientific journal Science Advances. The researchers are active at the Department of Physics and the Department of Mechanics and Maritime Sciences at Chalmers University of Technology, as well as at the Norwegian University of Science and Technology, NTNU) in Trondheim, Norway.<br /><br /></li> <li><span style="background-color:initial">The article </span><a href="">Copper catalysis at operando conditions—bridging the gap between single nanoparticle probing and catalyst-bed-averaging​</a><span style="background-color:initial"> </span>is written by David Albinsson, Astrid Boje, Sara Nilsson, Christopher Tiburski, Anders Hellman, Henrik Ström and Christoph Langhammer and was recently published in the scientific journal Nature Communications. The researchers are active at the Department of Physics and the Department of Mechanics and Maritime Sciences at Chalmers, as well as at the Norwegian University of Science and Technology, (NTNU), in Trondheim, Norway.</li></ul></div></div> <img src="/SiteCollectionImages/Institutioner/F/750x340/750x340_llustration2.jpg" alt="" style="margin:5px" /><br /></div> <br />Tue, 03 Nov 2020 07:00:00 +0100 to make perfect edges in 2D-materials<p><b>Ultrathin materials such as graphene promise a revolution in nanoscience and technology. Researchers at Chalmers University of Technology, Sweden, have now made an important advance within the field. In a recent paper in Nature Communications they present a method for controlling the edges of two-dimensional materials using a ‘magic’ chemical.</b></p><div><div>​</div> <img src="/SiteCollectionImages/Institutioner/F/Blandade%20dimensioner%20inne%20i%20artikel/500_Battulga%20Munkhbat-200924.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;height:166px;width:130px" /><span style="background-color:initial">“</span><span style="background-color:initial">Our method makes it possible to control the edges – atom by atom – in a way that is both easy and scalable, using only mild heating together with abundant, environmentally friendly chemicals, such as hydrogen peroxide,” says Battulga Munkhbat, a postdoctoral researcher at the Department of Physics at Chalmers University of Technology, and first author of the paper. </span><div><br /></div> <div>Materials as thin as just a single atomic layer are known as two-dimensional, or 2D, materials. The most well-known example is graphene, as well molybdenum disulphide, its semiconductor analogue. Future developments within the field could benefit from studying one particular characteristic inherent to such materials – their edges. </div> <div>Controlling the edges is a challenging scientific problem, because they are very different in comparison to the main body of a 2D material. For example, a specific type of edge found in transition metal dichalcogenides (known as TMD’s, such as the aforementioned molybdenum disulphide), can have magnetic and catalytic properties. </div> <div><br /></div> <div><span style="background-color:initial">Typical TMD materials have edges which can exist in two distinct variants, known as zigzag or armchair. These alternatives are so different that their physical and chemical properties are not at all alike. For instance, calculations predict that zigzag edges are metallic and ferromagnetic, whereas armchair edges are semiconducting and non-magnetic. Similar to these remarkable variations in physical properties, one could expect that chemical properties of zigzag and armchair edges are also very different. If so, it could be possible that certain chemicals might ‘dissolve’ armchair edges, while leaving zigzag ones unaffected. </span><br /></div> <div><span style="background-color:initial"><br /></span></div> <div>Now, such a ‘magic’ chemical is exactly what the Chalmers researchers have found – in the form of ordinary hydrogen peroxide. At first, the researchers were completely surprised by the new results. </div> <div><br /></div> <div>“It was not only that one type of edge was dominant over the others, but also that the resulting edges were extremely sharp – nearly atomically sharp. This indicates that the ‘magic’ chemical operates in a so-called self-limiting manner, removing unwanted material atom-by-atom, eventually resulting in edges at the atomically sharp limit. The resulting patterns followed the crystallographic orientation of the original TMD material, producing beautiful, atomically sharp hexagonal nanostructures,” says Battulga Munkhbat.</div> <div><br /></div> <div>The new method, which includes a combination of standard top-down lithographic methods with a new anisotropic wet etching process, therefore makes it possible to create perfect edges in two-dimensional materials.</div> <img src="/SiteCollectionImages/Institutioner/F/Blandade%20dimensioner%20inne%20i%20artikel/Timur%20Shegai-webb_NY.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;height:166px;width:130px" /></div> <div>​<br /><div>“This method opens up new and unprecedented possibilities for van der Waals materials (layered 2D materials). We can now combine edge physics with 2D physics in one single material. It is an extremely fascinating development,” says Timur Shegai, Associate Professor at the Department of Physics at Chalmers and leader of the research project. </div> <div><br /></div> <div>These and other related materials often attract significant research attention, as they enable crucial advances within in nanoscience and technology, with potential applications ranging from quantum electronics to new types of nano-devices. These hopes are manifested in the Graphene Flagship, Europe’s biggest ever research initiative, which is coordinated by Chalmers University of Technology. </div> <div><br /></div> <div>To make the new technology available to research laboratories and high-tech companies, the researchers have founded <a href="">a start-up company ​</a>that offers high quality atomically sharp TMD materials. The researchers also plan to further develop applications for these atomically sharp metamaterials.</div> <div><br /></div> <div><strong>Text:</strong> Mia Halleröd Palmgren and Joshua Worth</div> <div><strong>Portrait pictures: </strong>Anna-Lena Lundqvist</div> <a href=""><div><br /></div> <div><div><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/icgen.gif" alt="" />Read the press release and download high resolution images.​​​​</div></div></a></div> <div> <h2 class="chalmersElement-H2">More on the publication </h2> <div>The paper <a href="">Transition metal dichalcogenide metamaterials with atomic precision​</a> recently appeared in Nature Communications The article is written by Battulga Munkhbat, Andrew Yankovich, Denis Baranov, Ruggero Verre, Eva Olsson and Timur Shegai at the Department of Physics at Chalmers. </div> <div><h2 class="chalmersElement-H2"><span>For more information, please contact: </span></h2></div> <div><a href="/en/staff/Pages/Battulga-Munkhbat.aspx">Battulga Munkhbat</a>, Post Doc, Department of Physics, Chalmers University of Technology, Sweden, +46 73 995 34 79, <a href="">​</a></div> <div><br /></div> <div><a href="/en/staff/Pages/Timur-Shegai.aspx">Timur Shegai</a>, Associate Professor, Department of Physics, Chalmers University of Technology, Sweden, +46 31 772 31 23, <a href=""></a></div> </div>Mon, 19 Oct 2020 06:00:00 +0200 sensing substrate reveals intimate secrets hidden in ion dynamics of bodily fluids<p><b>​Researchers at Chalmers University of Technology in Sweden, with collaborators from the Hebrew University of Jerusalem (HUJI), have demonstrated a possibility to measure complex changes in ionic concentrations relevant for a series of neurophysiological disorders, such as multiple sclerosis (MS). The study recently appeared as a featured article in volume 20 (number 13) of the IEEE Sensors Journal.</b></p><div>​<img src="/SiteCollectionImages/Institutioner/MC2/News/zoran_konkoli_IMG_8922__350x305.jpg" alt="Picture of Zoran Konkoli." class="chalmersPosition-FloatRight" style="margin:5px" />&quot;In brief, we managed to find a way to establish a dialogue with an ionic solution with zinc and copper ions. Through that dialogue we were able to ask the system complex questions about its state,&quot; explains Zoran Konkoli (to the right), Associate Professor at the Electronics and Materials Systems Laboratory (EMSL) at the Department of Microtechnology and Nanoscience – MC2, who led the project. </div> <div> </div> <div>The notion of time is extremely important in the researchers’ approach. In a nutshell, they have constructed an intelligent sensing substrate that accumulates information over time. In such a way, unrelated events that a single-instance measurement might miss are all accounted for. The method itself is a hybrid between supervised and unsupervised learning. </div> <div>&quot;We taught the system to speak in terms of &quot;bar-codes&quot;, an electrical response pattern, related to different ionic states. What we have achieved is a prime example of what can happen when computer science (machine learning, reservoir computing, compression algorithms), physics (multiscale modelling), the science of microfluidics, and biochemistry (intrinsic of the brain biochemistry) meet&quot;, explains Zoran Konkoli. </div> <div> </div> <div>The key idea is to operate an environment sensitive dynamical system in the reservoir computing mode and augment it with an auxiliary input channel. The concept of the auxiliary input channel is central to the approach used. Researchers refer to it as &quot;the drive&quot;. The drive signal aids the sensing substrate in communicating the accumulated information more clearly, e.g. in the same way a prompter helps an actor in the theater. </div> <div> </div> <div>The HUJI team designed ion-sensitive electronics components (an ion sensitive constant phase element). The Chalmers team provided the communication protocol, form of a useful auxiliary input and most importantly the bar-codes to look for, all these being essentially a library of useful voltage input-output patterns. </div> <div>&quot;What is interesting is that these were generated through extensive theoretical simulations of the system, where the parameters of the model were calibrated against separate experimental results. Once the model has been built, we could perform thousands virtual experiments. The signal libraries were built by using rather involved genetic optimization techniques,&quot; says Zoran Konkoli.</div> <div> </div> <div><img src="/SiteCollectionImages/Institutioner/MC2/News/shlomo_yitzchaik_350x305.jpg" alt="Picture of prof Yitzchaik." class="chalmersPosition-FloatLeft" style="margin:5px" />Why bother with zinc and copper ions? The choice to focus on these ions was made under the guidance of the leader of the HUJI team, Professor Shlomo Yitzchaik <span style="background-color:initial">(to the left)</span><span style="background-color:initial">. As Professor Yitzchaik</span><span style="background-color:initial"> </span><span style="background-color:initial">explains, these ions are important biomarkers for a series of neurophysiological disorders:</span></div> <span></span><div></div> <div>&quot;Our studies showed that by monitoring zinc(II)-to-copper(II) ionic ratio in sera sample one can have useful information on the health condition of the patient. This method proved useful in monitoring the status of the neurodegeneration state of multiple sclerosis patients versus healthy ones. These sensors combined with the barcode methodology can open new avenues for the development of point-of-care sensing devices for immunological and inflammatory disorders, autism, Alzheimer’s disease, multiple sclerosis, skin diseases, and cancer that relies on neuropeptides as a recognition layer. The great future for this technology lies in wearable sensors contacting the skin for physiology-based emotion and stress detection systems. The ability to detect the biomarkers present in sweat and process the biological information with the barcode technology may lead for future wearable sensors as affective systems that will improve our quality of life,&quot; he says.</div> <div> </div> <div>The study is a collaboration between scientists from Chalmers and Hebrew University of Jerusalem (HUJI). From Chalmers, Vasileios Athanasiou and Zoran Konkoli contributed to the theoretical part of the research. Aldo Jesorka, Professor at the Department of Chemistry and Chemical Engineering, provided a very complex microfluidic component that the HUJI team used in their experiments. The work was supported by the EU FET Open grant RECORD-IT. </div> <div> </div> <div>Text: Michael Nystås and Zoran Konkoli</div> <div>Illustration: Vasileios Athanasiou and Zoran Konkoli</div> <div>Photo of Professor Shlomo Yitzchaik: Yoav Dudkevich</div> <div>Photo of Associate Professor Zoran Konkoli: Michael Nystås</div> <h3 class="chalmersElement-H3">Contact:</h3> <div>Zoran Konkoli, Associate Professor, Electronics and Materials Systems Laboratory, Department of Microtechnology and Nanoscience – MC2, Chalmers University of Technology, </div> <div> </div> <h3 class="chalmersElement-H3">Read the article in IEEE Sensors Journal &gt;&gt;&gt;</h3> <div>On Sensing Principles Using Temporally Extended Bar Codes</div> <div><a href=""></a></div> <div>doi: 10.1109/JSEN.2020.2977462</div> <div> </div> <h3 class="chalmersElement-H3">MORE ABOUT THE RESEARCH &gt;&gt;&gt;</h3> <div>The study demonstrates an indirect sensing concept on the one of the most challenging sensing problems: ion detection. In general, it is very hard to measure properties of ionic systems, especially if the ions of interest occur in very low concentrations and their number fluctuates in time. In the standard sensing setup, the flow of information is linear, from the object of interest, in this case an ionic solution, to the user who observes the system. Further, a typical measurement is a single instance event, in terms of time, though a repeated subsequent measurement might give an impression of continuity.</div> <div> </div> <div>This time, the researchers approached the problem differently. Instead of the traditional single instance &quot;measurement&quot; they thought more of a &quot;dialogue&quot; during which one interacts with the system over a longer time period. Such a temporally extended dialogue is much more informative than a single one-instance interaction. The biggest challenge was to develop a suitable language that can be used to communicate with the system of interest.</div> <div> </div> <div>As a guiding principle, the researchers used an indirect sensing algorithm developed within the RECORD-IT project coordinated by Zoran Konkoli, the SWEET algorithm, defined by three modules: (1) a dynamical system that interacts with the environment of interest (the sensing reservoir), (2) an auxiliary input channel that can be used to increase the intelligence of the system and query the system at the same time, and (3) a simple readout layer that is used to inspect the state of the sensing reservoir.</div>Wed, 14 Oct 2020 13:00:00 +0200 award to Chalmers physicist<p><b>​Chalmers Professor Björn Jonson has been awarded the prestigious Lise Meitner Prize by the European Physical Society (EPS). It is awarded to one or more researchers who have made outstanding contributions to nuclear science. ​​​​​</b></p><a href="/en/Staff/Pages/Bjorn-Jonson.aspx">​​<img src="/SiteCollectionImages/Institutioner/F/350x305/Bjorn_Jonson_180330_Portratt_webb_350x305.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;height:174px;font-weight:300;width:200px" /><span style="font-weight:300;background-color:initial"></span><span style="background-color:initial">​Björn Jonson</span>​</a><span style="background-color:initial"> has been engaged in research at Chalmers since 1967. His dynamic work is of fundamental </span><span style="background-color:initial">importance for the study of the nuclear structure and stability focused on exotic light halo nuclei at the </span><span style="background-color:initial">boundaries of nuclear stability. He is elected member of several academies of science and his work has been recognized internationally. He is a member of the Royal Swedish Academy of Sciences and was for seven years a member of the Nobel Committee for Physics. </span><a href="/en/departments/physics/news/Pages/Russian-Great-Gold-Medal-to-Chalmers-professor-.aspx">In 2018 he received the highest award of the Russian Academy of Sciences (RAS) - the Great Gold Medal named after the Russian scientist Mikhail Lomonosov. ​</a><div><span style="background-color:initial"><br /></span><div>Over the years, Björn Jonson has conducted research at CERN in Switzerland. CERN is one of the world's most powerful particle accelerator facilities. For almost two decades Jonson contributed to the successful development of the scientific programme at the ISOLDE research facility, for which he was scientific group leader for seven years. <br /><br /></div> <div>“I’m very happy to see all the successful work performed at the facility today. It’s also nice to receive a prize in honor of the prominent nuclear physicist Lise Meitner. In recent years, I have been engaged in various activities to highlight her contributions to nuclear science,” says Björn Jonson, Professor at the Department of Physics at Chalmers University of Technology. <br /><br /></div> <div>Björn Jonson has been one of the driving forces behind designating the “Lise Meitner House” in Kungälv (close to Gothenburg) a European Physical Historical site. </div> <div><br /></div> <div>Björn Jonson receives the Lise Meitner award 2020 for his development and application of on-line instrumentation and techniques, his precise and systematic investigation of properties of nuclei far from stability, and for shaping the scientific program at the on-line isotope separator facility ISOLDE, CERN.</div> <div>Björn Jonson shares the award for 2020 with Klaus Blaum, Heidelberg, and Piet Van Duppen, Leuven. </div> <div><br /></div> <div><strong style="background-color:initial">Text: </strong><span style="background-color:initial">Mia Halleröd Palmgren, </span><a href=""></a><span style="background-color:initial"> and</span><br /></div> <div>Göran Nyman, <a href=""></a><br /><span style="font-weight:700">Image:</span> Elena Puzynina, JINR<br /><br /></div> <div><strong>About the Lise Metiner Prize:</strong></div> <div>The Lise Meitner Prize is given biennially by the Nuclear Physics Division of the European Physical Society. It is awarded to one or more researchers who have made outstanding contributions to nuclear science. Such contributions may comprise experimental nuclear physics, theoretical nuclear physics and all areas of application of nuclear science. The prize consists of a Medal and a Diploma, in addition to a cash award. </div> <div>The award ceremony of the Lise Meitner Prize 2020 will take place during the ISOLDE workshop on 26 November 2020 as an online event.  ​</div> <div><br /></div> <div><a href=""><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/icgen.gif" alt="" />Read more on the Lise Meitner Prize 2020 on EPS' web site.  </a></div> <div><br /></div> <div><a href="" target="_blank"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/icgen.gif" alt="" />Read more on Björn Jonson’s research</a></div> <div><a href="" target="_blank"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/icgen.gif" alt="" />Learn more on ISOLDE, CERN</a></div> <div><a href="" target="_blank"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/ichtm.gif" alt="" />Read a news article on the inauguration of the “Lise Meitner House” as an EPS historic site (2016)</a></div> </div> ​Thu, 08 Oct 2020 15:00:00 +0200 to new medical technology research lab<p><b>​When a new medical technology research lab is built up at Sahlgrenska University Hospital, Dag Winkler, professor of physics and head of the Quantum Device Physics Laboratory (QDP) at MC2, will be one of the users.</b></p>&quot;The idea is that the new 21-channel system we are now building will be used at the new lab and coexist with the microwave measurements and treatments&quot;, explains Dag Winkler, who for many years also was head of department at MC2.<br /><br />Winkler's and his research colleagues' acclaimed project NeuroSQUID, is now preparing for its next phase. The project is funded by the Knut and Alice Wallenberg Foundation and is a collaboration between researchers at Chalmers, The Sahlgrenska Academy and Karolinska Institutet. The project has been going on since 2014 and is led by Dag Winkler.<br /><br />Researchers at NeuroSQUID have developed a unique MEG instrument (magnetoencephalography) with seven channels for measuring and mapping the brain. The construction of a new system with 21 channels is currently underway; a system to be used in the upcoming research lab.<br /><br />The project's final doctoral student in this round, Silvia Ruffieux, recently defended her thesis &quot;High-temperature superconducting magnetometers for on-scalp MEG&quot;.<br />&quot;It is now important to bring in new funding and staff who can continue with the development of the new MEG system with 21 channels. New sensors will be needed to equip the system with, and a lot of work in the clean room will be required from now on. We are in a turning point both financially and in terms of personnel&quot;, says Dag Winkler.<br /><br />The new research lab is a major investment in clinical research, in collaboration between Sahlgrenska University Hospital, Chalmers, The Sahlgrenska Academy and Region Västra Götaland. New methods for diagnosis and treatment - and in the long run better care - will be results of the new lab, which is expected to be inaugurated in May 2021.<br /><br />Text: Michael Nystås<br />Photo: Peter Widing<br /><br /><a href="/en/areas-of-advance/health/news/Pages/New-research-lab-for-cancer-treatment-and-new-diagnostics.aspx">Read more about the upcoming research lab</a> &gt;&gt;&gt;<br /><br /><a href="">Read more about the NeuroSQUID project</a> &gt;&gt;&gt;Wed, 07 Oct 2020 05:00:00 +0200 most sensitive optical receivers yet for space<p><b>​Communications in space demand the most sensitive receivers possible for maximum reach, while also requiring high bit-rate operations. A novel concept for laser-beam based communications, using an almost noiseless optical preamplifier in the receiver, was recently demonstrated by researchers at Chalmers University of Technology, Sweden.</b></p>In a new paper published in the scientific journal Nature: Light Science &amp; Applications, a team of researchers describes a free-space optical transmission system relying on an optical amplifier that, in principle, does not add any excess noise – in contrast to all other preexisting optical amplifiers, referred to as phase-sensitive amplifiers (PSAs).<br /><br />The researchers’ new concept demonstrates an unprecedented receiver sensitivity of just one photon-per-information bit at a data rate of 10 gigabits per second.<br />“Our results show the viability of this new approach for extending the reach and data rate in long-distance space communication links. It therefore also has the promise to help break through the present-day data-return bottleneck in deep-space missions, that space agencies around the world are suffering from today,” says Professor Peter Andrekson, head of the research group and author of the article together with PhD Ravikiran Kakarla and senior researcher Jochen Schröder at the Department of Microtechnology and Nanoscience – MC2, at Chalmers University of Technology.<br /><img src="/SiteCollectionImages/Institutioner/MC2/News/Super-sensitive-receiver_fig2_665x330.jpg" alt="Picture of research." style="margin:5px" /><br /><em>Fig 2. </em><span><em>Illustration of the difference between the spot size on Earth when using laser beam or a radio wave beam transmitter on the Moon. The diffraction of power with a laser beam is visibly substantially smaller.</em><span style="display:inline-block"><em> Illustration: Yen Strandqvist</em></span></span><br /><br />Substantially increasing the reach and information rate for future high-speed links will have big implications for technologies such as inter-satellite communication, deep-space missions, and earth monitoring with light detection and ranging (Lidar). Systems for such high-speed data connections are increasingly using optical laser beams rather than radio-frequency beams. A key reason for this is that the loss of power as the beam propagates is substantially smaller at light wavelengths, since the beam divergence is reduced. <br /><br />Nevertheless, over long distances, light beams also experience large loss. For example, a laser beam sent from the Earth to the Moon – around 400,000 kilometres – with a 10 cm aperture size, will experience a loss of power of around 80 dB, meaning only 1 part in 100 million will remain. As the transmittable power is limited, it is of critical importance to have receivers that can recover the information sent with as low power received as possible. This sensitivity is quantified as the minimum number of photons per information bit necessary to recover the data without error. <br /><br /><strong><img src="/SiteCollectionImages/Institutioner/MC2/News/peter_andrekson_170112_350x305.jpg" class="chalmersPosition-FloatRight" alt="Picture of Peter Andrekson." style="margin:5px" />The new concept from Chalmers</strong><br />In the new concept from Chalmers, information is encoded onto a signal wave, which along with a pump wave at different frequency generates a conjugated wave (known as an idler) in a nonlinear medium. These three waves are launched together into the free space. At the receiving point, after capturing the light in an optical fiber, the PSA amplifies the signal using a regenerated pump wave. The amplified signal is then detected in a conventional receiver.<br />“This approach fundamentally results in the best possible sensitivity of any pre-amplified optical receiver and also outperforms the current performance of all other state-of-the-art receiver technologies,” says Peter Andrekson (to the right). <br /><br />The system uses a simple modulation format encoded with a standard error correction code and a coherent receiver with digital signal processing for signal recovery. This method is straightforwardly scalable to much higher data rates if needed. It also operates at room temperature, meaning it can be implemented in space terminals and not only on the ground. <br /><br />The theoretical sensitivity limits of this approach are also discussed in the paper and compared to other existing methods, with the conclusion that the new approach is essentially the best possible for a very broad range of data rates.<br /><br />Illustrations: Yen Strandqvist<br />Photo of Peter Andrekson: Henrik Sandsjö<br /><br /><strong>Contact</strong><br />Peter Andrekson, Professor of Photonics, head of the Photonics Laboratory, Department of Microtechnology and Nanoscience – MC2, Chalmers University of Technology,  <br /><br /><strong>Read the article &gt;&gt;&gt;</strong><br />Ravikiran Kakarla, Jochen Schröder, and Peter A. Andrekson. One photon-per-bit receiver using near-noiseless phase-sensitive amplification. Nature: Light Science &amp; Applications 9, 153 (2020). <br /><a href=""> </a><br /><br /><strong>Funding &gt;&gt;&gt;</strong><br />This work was supported by the Swedish Research Council (grant VR-2015-00535), the Knut and Alice Wallenberg Foundation, and the European Research Council (project ERC-2018-PoC 813236).<br /><br /><strong>More about the research &gt;&gt;&gt;</strong><br />A widely studied approach uses power-efficient pulse position modulation formats along with nanowire-based photon-counting receivers needing cooling down to only a few Kelvin while operating at speeds below 1 Gbit/s. However, to achieve multi-Gbit/s data-rates that will be required in the future, systems relying on pre-amplified optical receivers together with advanced signal generation and processing techniques used in optical fiber communications are also being considered.<br /><br />With their new method, the Chalmers researchers demonstrated an unprecedented error-free, “black-box”-sensitivity of one photon-per-information-bit at a data rate of 10 Gbit/s. With 10 Watts of transmitter power, this receiver would allow for a link loss of 100 dB at this data rate. For transmission to/from Mars, a system with 10 Watt could support a data rate in the order of 10 Mbit/s, which is about 1000 faster than today rates (0.5–32 kbit/s).<br /><br /><strong>Watch news feature about the research on TV4 &gt;&gt;&gt;</strong><br /><a href=""></a>Thu, 01 Oct 2020 07:00:00 +0200 heavy element creation in neutron-star mergers<p><b>Violent collisions of neutron stars are believed to be the origin of, for example, gold and platinum. Now, subatomic physicists at Chalmers will explore how such heavy elements are formed. In a new project, granted SEK 29.6 million in funding from the Knut and Alice Wallenberg Foundation, they will perform novel experiments to understand how the laws of subatomic physics influence the collision of neutron stars. ​​​​</b></p><div><img src="/SiteCollectionImages/Institutioner/F/350x305/350x305Andreas%20Heinz-200924.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;width:250px;height:218px" /><div>“Recent breakthroughs in astronomical observations, especially the detection of gravitational waves, together with advances in instrumentation for subatomic physics experiments offer unique research opportunities.  We will be able to understand how nuclear fission impacts the creation of heavy elements in the collision of neutron stars. <br />I am thrilled to be a part of this endeavor and grateful to the Knut and Alice Wallenberg Foundation for making this research possible,” says Andreas H​einz, Associate Professor at the Department of Physics at Chalmers. <br /><br /></div> <div>Together with Doctor Håkan T. Johansson and Professor Thomas Nilsson, he will investigate how the laws of the subatomic world, and in particular nuclear fission, influence the creation of heavy elements in the universe. For five years, the Chalmers researchers will carry out innovative experiments at the European research facility CERN in Switzerland.<br /><br /></div> <div>“To understand how heavy elements are formed, astronomical observations alone are not sufficient. It is also necessary to understand the underlying nuclear physics processes caused by a high flux of neutrons,” says Andreas Heinz, leader of the recently founded project. <br /><br /></div> <div><a href="">In total, the Knut and Alice Wallenberg Foundation has granted SEK 541 million to 18 outstanding basic research projects in medicine, science and technology that are considered to have the possibility to lead to future scientific breakthroughs. ​</a><br /><br /></div> <div><a href="/en/news/Pages/Large-grants-enables-new-cutting-edge-research.aspx">Out of the 18 projects, three will be conducted at Chalmers​</a>. At the Department of Physics, <a href="/en/departments/physics/news/Pages/Bright-prospects-for-revolutionary-optics-research.aspx">Professor Mikael Käll will lead a project on light sources of the future</a>. At the Department of Space, Earth and Environment, <a href="/en/departments/see/news/Pages/KAW-grant-cosmic-dust.aspx">Professor Kirsten Kraiberg Knudsen will lead a project on the origin and fate of dust in the universe.​</a></div> <div><br /></div> <div><strong>Text: </strong>Mia Halleröd Palmgren</div> <div><strong>Portrait photo:</strong> Anna-Lena Lundqvist</div> <div><br /></div> <h2 class="chalmersElement-H2">More about the project and the financier</h2> <div><span style="background-color:initial">The research project &quot;Creation of heavy elements in neutron-star mergers&quot; has been granted SEK 29,600,000 for five years by the Knut and Alice Wallenberg Foundation.</span><br /></div> <div>The project is led by<a href="/sv/personal/Sidor/Andreas-Heinz.aspx"> Andreas Heinz​,​</a> Associate Professor at the Department of Physics at Chalmers. Professor <a href="/sv/personal/Sidor/Thomas-Nilsson.aspx">Thomas Nilsson</a> and Doctor <a href="/en/staff/Pages/Håkan-T-Johansson.aspx">Håkan T. Johansson​</a>, both from the same department, are also participating in the project. <a href="" style="outline:0px">The Knut and Alice Wallenberg Foundation</a> is Sweden's largest private research funder and one of the largest in Europe.</div> <div><br /></div> <div><strong>What is a neutron star?</strong></div> <div><span style="background-color:initial">A neutron star is the remaining core of a star, which had about 10-20 times the mass of the sun. The core of such a star collapses once it runs out of material for nuclear fusion. Infalling matter bounces back from the extremely dense core, leading to a supernova explosion. The remaining core forms a neutron star with a density as high, or higher, than that of an atomic nucleus – with masses similar to those of the sun within a sphere of a few kilometers in diameter. The exact composition of neutron stars is not known. They are, short of black holes, the densest known objects in the universe.</span></div></div> Wed, 30 Sep 2020 09:00:00 +0200 prospects for revolutionary optics research<p><b>The light sources of the future can be created with the help of lasers and artificial surfaces - meta surfaces - thinner than a wavelength of light. Optics research is facing a revolutionary development. Researchers at Chalmers are at the forefront in this field and have been granted more than SEK 38 million in funding from the Knut and Alice Wallenberg Foundation. ​</b></p><div>Vertical-cavity surface-emitting lasers (VCSELs) are becoming the laser of choice for a rapidly increasing number of applications, including optical communication and 3D sensing for smart phones and autonomous vehicles. <br /><br /><img src="/SiteCollectionImages/Institutioner/F/350x305/350x305MikaelKall_200924.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;height:171px;width:200px" /><span style="background-color:initial"></span><span style="background-color:initial">“By combining world-leading expertise on VCSEL and nanophotonics research, we take on the challenge of </span><span style="background-color:initial">merging the fields of semiconductor laser technology and flat optics based on 2D nanophotonic metasurfaces to realize monolithic metasurface emitting lasers (MELs). We believe that this new miniaturized light source will be so powerful, versatile, compact, cost- and energy-effcient that it will have disruptive and generic impact on photonics across a huge range of fields and applications,” says Professor Mikael Käll at the Department of Physics at Chalmers and Principal Investigator of the project “Metasurface-Emitting Lasers: Tomorrows Light Sources for Applied Photonics”. </span></div> <div><div><br /><img src="/SiteCollectionImages/Institutioner/F/Blandade%20dimensioner%20inne%20i%20artikel/METAYTA_WEBB.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;width:330px;height:246px" /><span style="background-color:initial">With the help of the new technology, the researchers can control light in sophisticated ways.  For example, metasurface emitting lasers could be used to create light fields for optical sensing in three dimensions, to generate extremely strong laser beams and for applications within biophotonics. </span><br /></div> <div>Mikael Käll and his research colleagues in the project have expertise in nanooptics, vertical-cavity surface-emitting lasers, optical calculation methods, and biophotonics. Furthermore, they have access to world-leading infrastructure at Chalmers.<br /><br /></div> <div><a href="">In total, Knut and Alice Wallenberg Foundation has granted SEK 541 million to 18 outstanding basic research projects in medicine, science and technology that are considered to have the opportunity to lead to future scientific breakthroughs. ​</a><br /><br /></div> <div><a href="/en/news/Pages/Large-grants-enables-new-cutting-edge-research.aspx">Out of the 18 projects, three will be conducted at Chalmers.​</a> At the Department of Physics, <a href="/en/departments/physics/news/Pages/Major-grant-to-explore-heavy-element-creation-in-neutron-star-mergers.aspx">Associate Professor Andreas Heinz will lead a project about the creation of heavy elements in neutron-star mergers</a>. At the Department of Space, Earth and Environment,<a href="/en/departments/see/news/Pages/KAW-grant-cosmic-dust.aspx"> Professor Kirsten Kraiberg Knudsen will lead a project on the origin and fate of dust in our universe​</a>. <br /><br /><div><span style="font-weight:700">Text: </span>Mia Halleröd Palmgren</div> <div><span style="font-weight:700">Portrait photo:</span> Anna-Lena Lundqvist​<br /><strong>Image:</strong> Daniel Andrén <span style="background-color:initial"> </span><span style="background-color:initial">-​ </span><span style="background-color:initial">Section of a metalens fabricated in the cleanroom at </span><span style="background-color:initial">Chalmers.</span></div> <span></span><div></div> <br /><span></span><h2 class="chalmersElement-H2">More on the project and the financier:</h2> <div>The research project &quot;Metasurface-Emitting Lasers: Tomorrows Light Sources for Applied Photonics” has been granted SEK 38,100,000 over five years by the Knut and Alice Wallenberg Foundation.</div> <div>Professor <a href="/en/staff/Pages/Mikael-Käll.aspx">Mikael Käll</a> is the Principal Investigator of the project and the work will be carried out in collaboration with Professor <a href="/en/staff/Pages/Åsa-Haglund.aspx">Åsa Haglund​</a>, Professor <a href="/en/staff/Pages/Anders-Larsson.aspx">Anders Larsson</a>, Associate Professor <a href="/en/staff/Pages/Philippe-Tassin.aspx">Philippe Tassin</a> and Associate Professor <a href="/en/staff/Pages/Ruggero-Verre.aspx">Ruggero Verre</a>. </div> <div><a href="">The Knut and Alice Wallenberg Foundation​</a> is Sweden's largest private research funder and one of the largest in Europe.</div></div></div> ​Wed, 30 Sep 2020 09:00:00 +0200 grants enable new cutting-edge research<p><b>​Three research groups at Chalmers University of Technology will receive SEK 96 million from the Knut and Alice Wallenberg Foundation. It enables major basic research efforts on violent collisions between neutron stars, the origin of cosmic dust and its fate, and the light sources of the future that can be created with the help of lasers and artificial surfaces that are thinner than a light wavelength.​</b></p>​<span style="background-color:initial">With this year's call, Knut and Alice Wallenberg Foundation has during the years 2011–2020 granted funding for 218 basic research projects totaling SEK 6.8 billion. These are the three projects that will start at Chalmers.<br /></span> <h2 class="chalmersElement-H2">&quot;Creation of heavy elements in neutron-star mergers&quot;</h2> <div><img src="/SiteCollectionImages/20200701-20201231/Andreas_Heinz_200924_250x350px.jpg" alt="Andreas Heinz." class="chalmersPosition-FloatRight" style="margin:5px 10px" />Violent collisions of neutron stars are believed to be the origin of, for example, gold and platinum. Now, subatomic physicists at Chalmers will explore how such heavy elements are formed, to understand how the laws of subatomic physics influence the collision of neutron stars. Recent breakthroughs in astronomical observations, especially the detection of gravitational waves, together with advances in instrumentation for subatomic physics experiments offer unique research opportunities.  </div> <div><br /></div> <div>“We will be able to understand how nuclear fission impacts the creation of heavy elements in the collision of neutron stars. I am thrilled to be a part of this endeavor and grateful to the Knut and Alice Wallenberg Foundation for making this research possible,” says Andreas Heinz, Associate Professor at the Department of Physics at Chalmers. </div> <div><br /></div> <div>The research project has been granted SEK 29,600,000 for five years. The project is led by Andreas Heinz, associate professor at the Department of Physics at Chalmers. Professor Thomas Nilsson and doctor Håkan T. Johansson, both from the same department, are also participating in the project.</div> <div><br /></div> <div><a href="/en/departments/physics/news/Pages/Major-grant-to-explore-heavy-element-creation-in-neutron-star-mergers.aspx"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/ichtm.gif" alt="" />Major grant to explore heavy element creation in neutron-star mergers</a></div> <div><h2 class="chalmersElement-H2"><span>”The Origin and Fate of Dust in our Universe”</span></h2></div> <div><img src="/SiteCollectionImages/20200701-20201231/KraibergKnudsenKirsten_fotoMarkusMarceticM3A6854_250x350px.jpg" alt="Kirsten Kraiberg Knudsen." class="chalmersPosition-FloatRight" style="margin:5px 10px" />Cosmic dust grains are microscopic particles that affect virtually every process in the Universe, from the formation of planets and stars to black holes and entire galaxies. Without dust, our solar system would not have formed. But where do the dust grains come from, and how do they develop?  Four researchers at Chalmers and University of Gothenburg will try to answer this in a joint project.</div> <div><br /></div> <div>&quot;The fact that we can combine our special competencies in this project means that we can cross subject boundaries to deal with a very fundamental question in astronomy, namely what is the origin and fate of dust in the universe&quot;, says Kirsten Kraiberg Knudsen at the Department of Space, Earth and Environment at Chalmers.</div> <div><br /></div> <div>The five-year long project is granted SEK 27,700,000. Kirsten Kraiberg Knudsen, who is an associate professor of extragalactic astronomy, is the Principal Investigator and the work will be carried out in collaboration with colleagues professor Wouter Vlemmings and professor Susanne Aalto at Chalmers, and professor Gunnar Nyman, at the University of Gothenburg.</div> <div><br /></div> <div><a href="/en/departments/see/news/Pages/KAW-grant-cosmic-dust.aspx"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/ichtm.gif" alt="" />On dusty roads through the Universe</a></div> <h2 class="chalmersElement-H2">”Metasurface-Emitting Lasers: Tomorrows Light Sources for Applied Photonics”</h2> <div><img src="/SiteCollectionImages/20200701-20201231/Mikael_Kall_200924_250x350px.jpg" alt="Mikael Käll." class="chalmersPosition-FloatRight" style="margin:5px 10px" />The light sources of the future can be created with the help of lasers and artificial surfaces – meta surfaces – thinner than a wavelength of light. Optics research is facing a revolutionary development, where vertical-cavity surface-emitting lasers (VCSELs) are becoming the laser of choice for a rapidly increasing number of applications. </div> <div><br /></div> <div>“By combining world-leading expertise on VCSEL and nanophotonics research, we take on the challenge of merging the fields of semiconductor laser technology and flat optics based on 2D nanophotonic metasurfaces to realize monolithic metasurface emitting lasers (MELs). We believe that this new miniaturized light source will be powerful, versatile, compact, cost- and energy-efficient,” says professor Mikael Käll at the Department of Physics.</div> <div><br /></div> <div>The research project has been granted SEK 38,100,000 over five years. Professor Mikael Käll is the Principal Investigator and the work will be carried out in collaboration with professor Åsa Haglund, professor Anders Larsson, associate professor Philippe Tassin and associate professor Ruggero Verre. </div> <div><br /></div> <div><a href="/en/departments/physics/news/Pages/Bright-prospects-for-revolutionary-optics-research.aspx"><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/ichtm.gif" alt="" />Bright prospects for revolutionary optics research</a></div> <div><br /></div> <h3 class="chalmersElement-H3"><span>Knut and Alice Wallenberg Foundation </span></h3> <div><span style="background-color:initial">... is the largest private funder of scientific research in Sweden, and one of the largest in Europe. The Foundation’s aim is to benefit Sweden by supporting Swedish basic research and education, primarily in medicine, technology and the natural sciences. This is achieved by awarding grants to excellent researchers and projects.</span><br /></div> <div>More than SEK 29 billion in grants has been awarded since the Foundation was established, with annual funding of around SEK 2,0 billion in recent years.</div> <div><a href=""><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/icgen.gif" alt="" />Read the pressrelease from Knut and Alice Wallenberg Foundation​</a></div> <div><br /></div> <div><strong>Text</strong>: <em>Anita Fors, Mia Halleröd Palmgren and Christian Löwhagen</em></div> <div><strong>Photo:</strong> <em>Anna-Lena Lundgren and Markus Marcetic/ Young Academy of Sweden​</em></div> Wed, 30 Sep 2020 09:00:00 +0200 New Spin on Topological Quantum Material<p><b>​Researchers at Chalmers University of Technology, Sweden, with collaborators in Germany and China, have discovered a new spin polarization in Tungsten di-telluride (WTe2), a topological Weyl semimetal candidate. These experimental findings can pave the way for the utilization of spin currents in developing the next generation of faster and energy-efficient spintronic and quantum technologies. The results are recently published in the journal Advanced Materials.</b></p><div><span style="background-color:initial">Topological quantum materials have attracted significant attention in condensed matter physics and information technology because of their unique band structure with topologically protected electronic states. After the realization of graphene and topological insulators, recently, Weyl semimetals were discovered with topological electronic properties. In contrast to the Schrödinger equation used to describe the electronic behavior in conventional materials and the Dirac equation for graphene and surface states of topological insulators, in Weyl semimetals, they follow the Weyl principles, proposed by Herman Weyl in 1929.</span><br /></div> <div><br /></div> <div>In these Weyl semimetals, the conduction and valence bands cross at specific points in momentum space, known as Weyl nodes. These nodes are topologically secured with opposite chirality in bulk with linear band dispersions. The appealing revelation in a Weyl semimetal is the presence of nontrivial surface states that connect the projections of Weyl nodes on the surface, called Fermi-arc. It has been shown that such a Weyl semimetal candidate WTe2 hosts unique electronic transport phenomena such as chiral anomaly, unconventional quantum oscillations, colossal magnetoresistance, spin Hall effect, and quantum spin Hall states, which opens a new era for physics experiments. </div> <div><br /></div> <div><img src="/SiteCollectionImages/Institutioner/MC2/News/saroj_prasad_dash_350x305.jpg" alt="Picture of Saroj Dash." class="chalmersPosition-FloatLeft" style="margin:5px" />In the present experiment​, researchers at Chalmers detected an unconventional spin current in Weyl semimetal WTe2, which is parallel to the applied electric field. The generated spin polarization in WTe2 is found to be different from the <a href="/en/departments/mc2/news/Pages/Spin-Hall-effect-in-Weyl-semimetal-for-Energy-efficient-Information-Technology.aspx" target="_blank">already known​</a> conventional spin-Hall and Rashba-Edelstein effects. </div> <div>&quot;Such a new spin-polarization component can be possible due to its broken crystal symmetry combined with large Berry curvature, spin-orbit interaction, and novel spin-texture of WTe2,&quot; explains Associate Professor Saroj Prasad Dash (to the left), who leads the research group at the Quantum  Device Physics Laboratory (QDP), the Department of Microtechnology and Nanoscience – MC2, Chalmers University of Technology.</div> <div><br /></div> <div>The spin polarization in WTe2 is electrically detected by using both direct and its inverse phenomenon, obeying Onsager reciprocity relation. A robust and practical method for electrical creation and detection of spin polarization is demonstrated and utilized for efficient spin injection and detection in a graphene channel up to room temperature. </div> <div><img src="/SiteCollectionImages/Institutioner/MC2/News/bing_zhao_2020_350x305.jpg" alt="Photo of Bing Zhao." class="chalmersPosition-FloatRight" style="margin:5px" /><br />&quot;These findings open opportunities for utilizing topological Weyl materials as non-magnetic spin sources in all-electrical 2D spintronics&quot;, states Bing Zhao (to the right),  researcher at QDP, and the first author of the paper.</div> <div>He continues:</div> <div>&quot;Moreover, the findings have great potential for utilizing topological semimetals in spintronic circuits and quantum technologies. The electrical creation and detection of spin polarization in topological Weyl semimetal can be useful for switching magnetization of ferromagnets for its use in the spin-orbit torque effect in spintronic memory and logic technologies. Furthermore, such layered topological semimetal can be combined with superconductors and ferromagnets to use in topological quantum technologies&quot;.</div> <div> </div> <div>The devices were nanofabricated in the state-of-the-art  cleanroom facility at MC2, and measured at the Quantum Device Physics Laboratory. Theoretical calculations were performed in collaboration with Max Planck Institute of Microstructure Physics, Halle, Germany, and University of Science and Technology Beijing, China. </div> <div><br /></div> <div>The Chalmers researchers acknowledge financial support from the European Union Graphene Flagship, Swedish Research Council, VINNOVA 2D Tech center, and AoA Materials and EI Nano program at Chalmers University of Technology.</div> <div><br /></div> <div>Illustration: Bing Zhao et al</div> <div>Photo of Saroj Prasad Dash: Oscar Mattsson</div> <div>Photo of Bing Zhao: Private</div> <div><br /></div> <div><strong>For further information &gt;&gt;&gt;</strong></div> <div>Saroj P. Dash, Associate Professor, Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience – MC2, Chalmers University of Technology, Gothenburg, Sweden, +46 31 772 5170,</div> <div><br /></div> <div><span style="background-color:initial"><strong>Read the full paper in Advanced Materials &gt;&gt;&gt;</strong></span><br /></div> <div>Unconventional Charge–Spin Conversion in Weyl‐Semimetal WTe2, Bing Zhao, Bogdan Karpiak, Dmitrii Khokhriakov, Annika Johansson, Anamul Md Hoque, Xiaoguang Xu, Yong Jiang, Ingrid Mertig, Saroj P. Dash; Advanced Materials, 2000818 (2020). <br /><a href="" target="_blank">​</a></div>Thu, 24 Sep 2020 09:00:00 +0200 an ultrafast train of promising X-ray pulses<p><b>​High-intensity X-ray sources are essential diagnostic tools for science, technology and medicine. Such X-ray sources can be produced in laser-plasma accelerators, where electrons emit short-wavelength radiation due to their betatron oscillations in the plasma wake of a laser pulse.</b></p><span style="background-color:initial"><a href="">In a recent paper, published in Scientific reports,​</a> Vojtěch Horný and Tünde Fülöp at the Department of Physics at Chalmers, present a way to generate an ultrafast “attosecond betatron radiation pulse train”. </span><span style="background-color:initial">​</span><div><span style="background-color:initial"></span><span style="background-color:initial"><br /></span><span></span><img src="/SiteCollectionImages/Institutioner/F/170x170px/170x170_VojtechHorny.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px" /><span style="background-color:initial"></span><div><span style="background-color:initial">​“It improves the resolution of diagnostics techniques based on betatron radiation by an order of magnitude. The promising applications include the X-ray absorption spectroscopy of warm dense matter or the scanning of fundamental processes such as chemical reactions and phase transitions occurring at the timescale of femtoseconds,” says researcher Vojtěch Horný at the Department of Physics at Chalmers.<br /><br /><div>Betatron radiation is the hard X-rays which are emitted by electrons accelerated at the plasma wave after the intense laser interaction with a gaseous target. The researchers modified such a scheme by adding another delayed laser pulse, which separates the accelerated electron bunch into a series of equidistant micro-bunches.</div> <div><br /></div> <div>As a result, the emitted betatron radiation is modulated as well and can thus be interpreted as a train of the attosecond X-ray pulses - separated by the half of the modulator pulse wavelength</div> <div>The new results are published in collaboration with colleagues in the Czech Republic and China. </div> <div><span style="background-color:initial;font-weight:700"><br /></span></div> <div><span style="background-color:initial;font-weight:700">Text: </span><span style="background-color:initial">Mia Halleröd Palmgren​</span></div> <h2 class="chalmersElement-H2"><span>For more information, please contact: </span></h2> <div><a href="/en/Staff/Pages/Vojtech-Horny.aspx">Vojtěch Horný</a> , Researcher, Department of Physics, Chalmers University of Technolgy, <a href=""> ​</a><span style="background-color:initial"><br /></span></div> <div><br /></div> <div><div><span style="background-color:initial"><a href="/sv/personal/Sidor/Tünde-Fülöp.aspx"><span>Tünde Fülöp,​</span> </a>Professor, Department of Physics, Chalmers University of Technology, </span><a href=""></a></div></div></span></div></div>Thu, 24 Sep 2020 00:00:00 +0200 ultrastrong coupling at room temperature<p><b>​Physicists at Chalmers, together with colleagues in Russia and Poland, have managed to achieve ultrastrong coupling between light and matter at room temperature. The discovery is of importance for fundamental research and might pave the way for advances within, for example, light sources, nanomachinery, and quantum technology.​​​​</b></p><div>A set of two coupled oscillators is one of the most fundamental and abundant systems in physics. It is a very general toy model that describes a plethora of systems ranging from guitar strings, acoustic resonators, and the physics of children’s swings, to molecules and chemical reactions, from gravitationally bound systems to quantum cavity electrodynamics. The degree of coupling between the two oscillators is an important parameter that mostly determines the behaviour of the coupled system. However, the question is rarely asked about the upper limit by which two pendula can couple to each other – and what consequences such coupling can have.<br /><br /></div> <div>The newly presented results, published in Nature Communications, offer a glimpse into the domain of the so called ultrastrong coupling, wherein the coupling strength becomes comparable to the resonant frequency of the oscillators. The coupling in this work is realised through interaction between light and electrons in a tiny system consisting of two gold mirrors separated by a small distance and plasmonic gold nanorods. On a surface that is a hundred times smaller than the end of a human hair, the researchers have shown that it is possible to create controllable ultrastrong interaction between light and matter at ambient conditions – that is, at room temperature and atmospheric pressure. <br /><img src="/SiteCollectionImages/Institutioner/F/Blandade%20dimensioner%20inne%20i%20artikel/DenisBaranov_port.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;width:135px;height:173px" /><br /></div> <div>” We are not the first ones to realise ultrastrong coupling. But generally, strong magnetic fields, high vacuum and extremely low temperatures are required to achieve such a degree of coupling. When you can perform it in an ordinary lab, it enables more researchers to work in this field and it provides valuable knowledge in the borderland between nanotechnology and quantum optics,” says Denis Baranov, a researcher at the Department of Physics at Chalmers and the first author of the scientific paper. </div> <div><br /></div> <div><h2 class="chalmersElement-H2">A unique duet where light and matter intermix into a common object​</h2> <div> <span style="background-color:initial">To understand the system the authors have realised, one can imagine a resonator, in this case represented by two gold mirrors separated by a few hundred nanometers, as a single tone in music. The nanorods fabricated between the mirrors affect how light moves between the mirrors and change their resonance frequency. Instead of just sounding like a single tone, in the coupled system the tone splits into two: a lower pitch, and a higher pitch. The energy separation between the two new pitches represents the strength of interaction. Specifically, in the ultrastrong coupling case, the strength of interaction is so large that it becomes comparable to the frequency of the original resonator. This leads to a unique duet, where light and matter intermix into a common object, forming quasi-par</span><span style="background-color:initial">ticles called polaritons. The hybrid character of polaritons provides a set of intriguing optical and electronic properties.</span></div></div> <div><br /></div> <div>The number of gold nanorods sandwiched between the mirrors controls how strong the interaction is. But at the same time, it controls the so-called zero-point energy of the system. By increasing or decreasing the number of rods, it is possible to supply or remove energy from the ground state of the system and thereby increase or decrease the energy stored in the resonator box. </div> <div><h2 class="chalmersElement-H2">The discovery allows researchers to play with the laws of nature</h2></div> <div>What makes this work particularly interesting is that the authors managed to indirectly measure how the number of nanorods changes the vacuum energy by “listening” to the tones of the coupled system (that is, looking at the light transmission spectra through the mirrors with the nanorods) and performing simple mathematics. The resulting values turned out to be comparable to the thermal energy, which may lead to observable phenomena in the future.</div> <div><br /></div> <div>“A concept for creating controllable ultrastrong coupling at room temperature in relatively simple systems can offer a testbed for fundamental physics. The fact that this ultrastrong coupling “costs” energy could lead to observable effects, for example it could modify the reactivity of chemicals or tailor van der Waals interactions. Ultrastrong coupling enables a variety of intriguing physical phenomena,” says Timur Shegai, Associate Professor at the Department of Physics at Chalmers and the last author of the scientific article. </div> <div>In other words, this discovery allows researchers to play with the laws of nature and to test the limits of coupling.<br /><img src="/SiteCollectionImages/Institutioner/F/Blandade%20dimensioner%20inne%20i%20artikel/TimurShegai_port.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;width:135px;height:173px" /><br /></div> <div>“As the topic is quite fundamental, potential applications may range. Our system allows for reaching even stronger levels of coupling, something known as deep strong coupling. We are still not entirely sure what is the limit of coupling in our system, but it is clearly much higher than we see now. Importantly, the platform that allows studying ultrastrong coupling is now accessible at room temperature,” says Timur Shegai.<br /><br /></div> <div><strong>Text: </strong>Mia Halleröd Palmgren</div> <div><strong>Portrait photos by:</strong> Johan Bodell (Timur Shegai) and Helén Rosenfeldt (Denis Baranov)</div> <div><br /></div> <div><a href=""><img class="ms-asset-icon ms-rtePosition-4" src="/_layouts/images/icgen.gif" alt="" />Read the press release and download high resolution images.​​</a><br /><br /></div> <h2 class="chalmersElement-H2">For more information, contact: </h2> <div><a href="/en/staff/Pages/Denis-Baranov.aspx">Denis Baranov</a>, Post Doc, Department of Physics, Chalmers University of Technology, +46 31 772 32 48, <a href=""></a></div> <div><br /></div> <div><a>Timur Shegai,</a> Associate Professor, Department of Physics, Chalmers University of Technology, +46 31 772 31 23, <a href="">​</a></div> <div><div><br /></div></div> <h2 class="chalmersElement-H2">More on the research and the scientific paper</h2> <div><ul><li>​The article <a href="">Ultrastrong coupling between nanoparticle plasmons and cavity photons at ambient conditions ​</a>has been published in Nature Communications. It is written by Denis Baranov, Battulga Munkhbat, Elena Zhukova, Ankit Bisht, Adriana Canales, Benjamin Rousseaux, Göran Johansson, Tomasz Antosiewicz and Timur Shegai. </li> <li><span style="background-color:initial">The researchers work at the Department of Physics and the Department of Microtechnology and Nanoscience at Chalmers, at Moscow Institute of Physics and Technology and at the Faculty of Physics, University of Warsaw.</span><br /></li> <li><span style="background-color:initial">The nanofabrication was performed at Chalmers. The interactions between light and matter were observed by using infrared microscopy. </span><br /></li> <li><span style="background-color:initial">The research at Chalmers was funded by the Swedish Research Council. </span><br /></li></ul></div> Wed, 23 Sep 2020 06:00:00 +0200