Events: Centre WACQT events at Chalmers University of TechnologyTue, 24 May 2022 13:48:25 +0200 [about Nanoscience] Levitating superconducting microspheres for macroscopic quantum experiments on a chip<p>Kollektorn MC2, and on Zoom</p><p>​​​Welcome to a seminar in the series SmallTalks [about Nanoscience] arranged by the Excellence Initiative Nano​. Martí Gutierrez Latorre, doctoral student at the department of Microtechnology and Nanoscience will talk about superconductors, microparticles, quantum technology. The seminar will be held both live and on Zoom  Join from PC, Mac, Linux, iOS or Android: ​</p>​<span style="font-weight:700;background-color:initial">Abstract:</span><span style="background-color:initial">​</span><span style="background-color:initial">Superconducting levitation is a fascinating phenomenon. Objects levitated in this way become extremely isolated from the environment, they have no internal mechanical losses, they can be manipulated by magnetic fields, and can be coupled to superconducting</span><div><div>quantum circuits. These advantages can be employed to generate quantum states with large, and massive objects, such as the proverbial SchrÅNodinger cat. Indeed, levitated superconductors have been proposed as a promising platform for macroscopic quantum</div> <div>experiments.</div> <div>Furthermore, due to their extreme isolation, a levitated superconducting microparticle is extremely sensitive to external perturbations. This means that they could be used as very precise force and acceleration sensors. </div> <div>In this presentation, we show the first steps towards realizing such experiments. I will introduce the working principle of superconducting levitation, show proof of concept of superconducting levitation on a chip, the progress so far, the challenges, and the outlook</div></div> <span style="background-color:initial">for this experiment.</span><div><span style="background-color:initial"><br /></span></div> <div><span style="background-color:initial"><br /></span></div> <span style="background-color:initial"><img src="/SiteCollectionImages/Areas%20of%20Advance/Nano/SmallTalk%20about%20Nanoscience/Decisiontree_EI_NanoSeminar2021_SC%203.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;height:275px;width:200px" /></span><div></div> <div><span style="background-color:initial"></span><span style="background-color:initial">​In c</span><span style="background-color:initial">ase you are not sure yet, whether you want to attend or not, we have prepared a decision tree that might help you! </span><div><span style="background-color:initial">Click to get a larger picture.</span></div> <span style="background-color:initial"> </span></div> computing in rare-earth-ion-doped crystals<p>Fasrummet</p><p>​​Speaker: Adam Kinos, Lund University</p><p class="MsoPlainText"><span style="background-color:initial"><strong>Abstract:</strong> Quantum computers are predicted to achieve significant speed-ups for certain applications when compared to classical computers. In this talk, I give an overview of quantum computing in rare-earth-ion-doped crystals. These systems can potentially have very high qubit densities and connectivities as the doped ions sit only nanometer apart in three dimensions. I discuss how these single-ion qubits could be read out via dedicated readout ions, and present the results of recent theoretical investigations that show that quantum processor nodes constructed in these materials can be tailored to contain between a few tens and 1000 qubits. Furthermore, the average number of qubits each qubit can interact with, denoted by the connectivity, can be partly tailored to lie between just a few and roughly 100. Lastly, I discuss how many such processor nodes are envisioned to be connected in a multi-node architecture.</span><br /></p> Professors Nano 2022 - research presentations<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>​The candidates will give their research presentations for Assistant Professor within the Excellence Initiative Nano. Welcome to listen to the presentations!</p>​<span style="background-color:initial">08.30 – 09.20</span><span style="background-color:initial;white-space:pre"> </span><span style="background-color:initial"><strong>Angela Grommet</strong>. </span><span style="background-color:initial">Title: Under Confinement: Molecular Separation, Transportation, and Reactivity Modulation​</span><div><span style="background-color:initial"></span><div>09.30 – 10.20<span style="white-space:pre"> </span><strong>Nils Johan Engelsen</strong>. Title: Quantum metrology with atoms and nanomechanical resonators​</div> <div>10.30 – 11.20<span style="white-space:pre"> </span><strong>Dmitry Baranov</strong>. Title: Nanocrystal Solids for Quantum Technology</div> <div>11.30 – 12.20<span style="white-space:pre"> </span><strong>Petr Stepanov</strong>. Title: Strong Electronic Correlations in Moiré Materials</div></div> <div><p class="MsoNormal"><span lang="EN-GB"><a href=""></a> </span><span lang="EN-US"></span></p></div>öteborg Mesoscopic Lecture: In Search for the Next Magic Stone<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>Welcome to Göteborg Mesoscopic Lecture, Summer Lecture 2022 with Zhi-Xun Shen, Depts Physics and Applied Physics, Stanford University, Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory​</p>Coffee will be served from 15.00​​<div><strong>​</strong><div><strong>Abstract:</strong><div><div>Materials demarcate periods of human civilization. The current period can be argued as defined by silicon, the magic stone that transformed the way we live. In this talk, I will discuss how the concept of quantum, and the 1st wave of quantum revolution led to the rise of silicon, the integrated circuit, Silicon Valley and the information age. I will then discuss the opportunities and challenges beyond silicon, and theoretical ideas and experimental tools needed to enable the next wave of quantum, in search for the next magic stone. </div></div> <div><br /></div> <div><span style="font-weight:700"><img src="/SiteCollectionImages/Institutioner/MC2/Föreläsningar/zhi-xun-shen.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px" />Bio:</span><div><span style="background-color:initial">Dr. Shen is a member of US Ntl Ac Sci, Am Ac Arts &amp; Sci, Chinese Ac Sci. His primary interest is novel quantum phenomena in materials. His work has been recognized  by the E.O. Lawrence Award, the Oliver E. Buckley Prize, the H. Kamerlingh Onnes Prize, and the Einstein Professorship Award of CAS. He has been Chief Scientist of SLAC and director of institutes of material and energy and of the Geballe Laboratory at Stanford University. He has mentored close to one hundred graduate students and post-docs and he is a co-inventor of several patents. </span></div></div> <div><br /></div></div></div> Phase Diagram of Cuprate Superconductors – a Balancing Act<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>Wel​come to a seminar with Zhi-Xun Shen, Depts Physics and Applied Physics, Stanford University, Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory ​</p><strong>​Abstract:</strong><div><div>High-temperature superconductivity in copper-based materials, with critical temperature well above what was anticipated by the BCS theory, remains a major unsolved physics problem more than 30 years after its discovery. The problem is fascinating because it is simultaneously simple - being a single band and ½ spin system, yet extremely rich - boasting d-wave superconductivity, pseudogap, spin and charge orders, and strange metal phenomenology. For this reason, cuprates emerge as the most important model system for correlated electrons – stimulating conversations on the physics of the Hubbard model, quantum critical points, Planckian metals and other topics. </div> <div>At the heart of this challenge is the complex electronic phase diagram consisting of intertwined states with unusual properties. Angle-resolved photoemission spectroscopy has emerged as the leading experimental tool to understand the electronic structure of these states and their relationships [1,2]. In this talk, I will describe our results on band structures and Fermi surfaces [3,4]; the d-wave superconducting state [5,6]; the birth of a metal from a Mott insulator [7-11]; the two energy scales of the pseudogap [8,9,12-13]; the temperature, doping and symmetry properties of the low energy pseudogap and its competition with superconductivity [14-18]; the missing quasiparticle and propensity to order [19-21], the interplay of electron-electron and electron-phonon interactions and the enhanced superconductivity [21-24], the incoherent metal sharply bounded by a critical doping [25-26], and the ubiquitous superconducting phase fluctuations [27,28]. The rich phenomenology suggests that a delicate balance between local Coulomb interaction and electron-phonon interaction holds the key to emerging physics in cuprates – unconventional superconductivity, anomalous metal, novel insulator, and intertwined orders.</div></div> <div><br /></div> <div><div>[1] A. Damascelli, Z. Hussain, and Z.-X. Shen, RMP, 75, 473 (2003)     <span style="white-space:pre"> </span><br />[2] J. Sobota, Y.He and Z.-X. Shen, RMP, 93, 025006 (2021)<br /><span style="background-color:initial">[3] D.S. Dessau et al., Phys. Rev. Lett. 66, 2160 (1991)<br /></span><span style="background-color:initial">[4] P. Bogdanov et al., Phys. Rev. Lett. 89, 167002 (2002)<br />[5] Z.-X. Shen et al., Phys. Rev. Lett. 70, 1553 (1993)<br /></span><span style="background-color:initial">[6] M. Hashimoto et al., Nature Physics 10, 483 (2014)<br />[7] B.O. Wells et al., Phys. Rev. Lett. 74, 964 (1995)<br /></span><span style="background-color:initial">[8] D.M. King et al., J. of Phys. &amp; Chem of Solids 56, 1865 (1995)<br />[9] Z.-X. Shen et al., Science 267, 343 (1995)<span style="white-space:pre"><br /></span></span><span style="background-color:initial">[10] N.P. Armitage et al., Phys. Rev. Lett. 87, 147003 (2001) <br />[11] J. He et al. PNAS 116, 9, 3449-3453 (Feb. 2019)<span style="white-space:pre"><br /></span></span><span style="background-color:initial">[12] D.S. Marshall et al., Phy. Rev. Lett. 76, 484 (1996)<br /></span><span style="background-color:initial;white-space:pre"></span></div> <div>[13] A.G. Loeser et al., Science 273, 325 (1996)<span style="white-space:pre"><br /></span>[14] K. Tanaka et al., Science 314, 1910 (2006)<br />[15] W.S. Lee et al., Nature 450, 81 (2007)<span style="white-space:pre"> </span><br />[16] M. Hashimoto et al., Nature Physics 6, 414-418 (2010) <br />[17] R.H. He et al., Science 331, 1579 (2011)<span style="white-space:pre"><br /></span>[18] M. Hashimoto et al., Nature Materials 14, 1 (2015)<br />[19] D.L. Feng et al., Science 289, 277 (2000)<span style="white-space:pre"><br /></span>[20] K.M. Shen et al., Phys. Rev. Lett., 93, 267002 (2004)<br />[21] KM Shen et al., Science 307, 901 (2005)<span style="white-space:pre"><br /></span>[22] A. Lanzara et al., Nature 412, 510 (2001)<br />[23] T. Cuk et al., Phys. Rev. Lett., 93, 117003 (2004)<span style="white-space:pre"><br /></span>[24] Yu He et al., Science, 362, 62 (Oct. 2018)      </div> <div>[25] I.M. Vishik et al., PNAS 109/45, 18332-18337 (2012)<br />[26] S.D. Chen et al., Science 366, 1099 (2019)</div> <div>[27] Y. He et al., Phys. Rev. X, 031068 (2021)<br />[28] S.D. Chen et al., Nature 601, 562 (2022)</div> <div><br /></div></div> <div><br /></div> categorical order theory of pulse scheduling for gate-based quantum computing<p>Luftbryggan, conference room, Kemivägen 9, MC2-huset</p><p>Axel Andersson, MPENM Engineering Mathematics and Computational Science, presents his master thesis titled &quot;A categorical order theory of pulse scheduling for gate-based quantum computing&quot;.​</p><div><div>Supervisor: Miroslav Dobsicek</div> <div>Opponent: Adam Yacine Smaili<br />​Exami​ner: Jonas Bylander</div> <div><br /></div> <div><strong>Abstract</strong>:</div> <div>We define a preorder on a function space of complex valued integrable functions on the non-negative real numbers. This preorder is then used to develop <span style="background-color:initial">a scheduling theory for microwave pulse schedules with an application for quantum computer experiments on superconducting circuits. The scheduling </span><span style="background-color:initial">theory is further developed in a categorical framework using a subcategory of Ord, the category of preordered sets and order-preserving mappings between </span><span style="background-color:initial">them.</span></div> <div>A Python library was written which applies the theory by translating IBM Qiskit OpenPulse schedules to Quantify schedules. This library was then <span style="background-color:initial">used to conduct single qubit characterisation experiments, such as resonator spectroscopy, two-tone spectroscopy, Rabi oscillation, Ramsey </span><span style="background-color:initial">oscillation, relaxation time (T1) and qubit state discrimination experiments.</span></div> <div><span style="background-color:initial"><br /></span></div> <div><span style="background-color:initial">To follow on zoom: </span><a href=""></a><span lang="EN-US" style="background-color:initial">    (</span><span style="background-color:initial">Password: 555</span><span lang="EN-US" style="background-color:initial">)</span></div> <p class="MsoNormal"><span lang="EN-US"></span></p> <div>​<br /></div></div> <div><br /></div> seminar - A nano focus on quantum materials<p>Chalmers Conference Centre, company, Chalmersplatsen 1, Kårhuset</p><p>​Save the date for the Excellence Initiative Nano Initiative seminar A nano focus on quantum materials.Read more on the conference page​</p>