Andreas Isacsson

Professor at Department of Physics

I engage both in research and teaching at the department. My main line of research is in the theory of carbon based nanoelectromechanical systems in the classical and quantum regime. For more information see the "Research" tab. In regards to teaching I am presently course responsible for the project based introductory course TIF275 for 1st year students in the Engineering Physics programme. More information is found under the "Teaching" tab.

Don't forget to check out the "Other activities" tab!

​Course responsible and Examiner for TIF275

TIF275, Fysikingenjörens verktyg, 10.5 hec. Kurshemsida HT15/VT16


TIF275, Fysikingenjörens verktyg, 10.5 hec. Kurshemsida HT14/VT15

​TIF275, Fysikingenjörens verktyg, 10.5 hec. Kurshemsida HT13/VT14

Mechanical and thermal properties of graphene and 2D-materials
 
From a mechanical perspective, graphene brought about something new. Being a genuine 2D crystalline membrane, it has remarkable mechanical properties, e.g. high tensile strength, which makes it unique in nanomechanical applications. Together with the atomic scale thickness and low mass, it opened up a promising route for NEMS applications in RF-technology, mass-sensing and quantum nanomechanical systems. The flexural vibrations, central to NEMS, are also the main carriers of heat in suspended graphene. Hence, more recently we have begun investigating the propagation of flexural phonons in graphene and the possibility to utilize graphene in phononic applications. 
 
 
 
Nonlinear response in nanoresonators
 
Graphene and carbon nanotube mechanical resonators are typically strongly nonlinear oscillators. This means that the response is no proportional to the driving force. These nonlinearities are typically due to the miniscule transverse dimensions of the systems and/or due to interactions with the surrounding electronic degrees of freedom. Part of our research is devoted to the study of the nonlinear response in these resonators, and, the often surprising resulting dynamical behavior of the systems.
 
Microscopic mechanisms of dissipation in nanoresonators
 
If one sets a string on a violin into vibration, it will eventually stop sounding and come to rest. The energy being partly converted into the sound we hear. Setting a nanoscale string into motion, the subsequent vibrations also decay and the system reaches equilibrium. However, the underlying microscopic mechanisms and the dynamics for how the energy initially stored in the vibrations redistribute is still largely unknown on the nanoscale. Part of our research aims at understanding the deceptively simple questions of why and how a nanoresonator relaxes to equilibrium.
 
 
 
Noise and fluctuations in nanomechanical resonators
Nanotechnology hold great promise in connection with sensor-technology. The small system sizes facilitate high sensitivity to small perturbations. On the other hand, this also makes nanodevices highly sensitive to perturbations from the environment, noise. In our research we have studied how noise in terms of particles diffusing on a nanoresonator changes the response. Among our main findings is that the coupling between diffusing partlices and a linear resonator mode can lead to an effectively nonlinear response as well as nontrivial dissipation behavior.
 
 
 
Mechanical systems in the quantum limit
Quantum mechanics of mechanical systems is a relatively new research area, where experiments only recently were able to show cooling of a mesoscopic mechanical system to its quantum ground state. The possibility to manipulate the quantum states of a mechanical system opens up for the kind of experiments that start resembling the early Gedanken experiments of the founders of quantum mechanics. These include highly nonclassical superposition states as well as entangled states. While such states are now routinely studied using QED/CQED the field of NEMS have now matured enough also for nonclassical mechanical states to be studied. Our focus in this exciting field of research lies in how one can exploit the strong nonlinearities of carbon nanoresonators to create highly non-classical states of motion.
​A complete list of publications is maintained on ResearcherID
​Collaboration with international groups in the field are an integral part of our activities.

Current international research collaborations
Prof. E. Mariani, University of Exeter, UK
Prof. A. Bachtold, ICFO, Barcelona, Spain

Recent international research collaborations
Prof. P. Hakonen, Aalto University, Helsinki, Finland.
Prof. E. Weig,  University of Konstanz, Germany.
Prof. M. Dykman, Michigan State University, US.
Prof. H. S. Park, Boston University, US.
​International Physicists' Tournament
The IPT is a yearly international event where university students in physics from around the world meet and present their solutions to open ended problems. The competition is a team competition that puts not only the skill in physics on test, but also centers around creativity, presentation technique, originality, and team work. Participating in the IPT is a great way for students to take responsibility for their own mini-research projects, all the way from formulating the questions, up to presenting and defending their results. It is also great way for students to build an international network of contacts with other students. Read more at the IPT website.

Published: Wed 13 Mar 2013. Modified: Wed 31 Oct 2018