Quantum Transport: Is there a difference between an electron and an autobus? by Thierry Giamarchi

This colloquium was originally recorded at the Aspen Center for Physics on Thursday, August 1, 2024. Our Colloquium series is for physicists, by physicists. Please see our "Public Lecture" playlists for videos intended for the general public.

The possibility to transport something (matter, spin, energy entropy) in response to proper stimulation is at the heart of the use we are making of most of the materials and driving the search for new ones with better transport properties. On the more fundamental side, looking at transport is a very strong theoretical challenge. The transport properties are deeply connected to the nature of the excitations thus to the physics that exists in the system at equilibrium, but depending on practical conditions one must also often deal with an out of equilibrium situation, for which some of the concepts that we take for granted, in equilibrium, such as the temperature potentially can break down.

The challenge and interest become even stronger with quantum objects since a host of new phenomena can appear. This ranges from the possibility to transport current without dissipation (superconductivity or superfluidity) or on the contrary to have systems that should have been excellent conductors that turn out to be insulators due to interactions and/or disorder. Recent progress in material science and in the field of cold atomic gases have allowed us to make deep progress in this field. I will discuss some of the examples of quantum transport in this talk, both for clean and disordered systems. I will address some of the success in connection with experimental realizations as well as some of the most burning problems that remain to be addressed or understood.

Thierry Giamarchi graduated from Ecole Normale Superieure in Paris and received his PhD from Paris XI University (now Paris-Saclay) in 1987. He has been a permanent member of the french CNRS since 1986, and between 1990-1992 was a postdoc/visitor at Bell Laboratories. In 2002 he moved as a full professor to the Quantum Matter Physics Department at the University of Geneva. His research work deals with the effects of interactions in low dimensional quantum systems, such as Luttinger liquids, and on the effects of disorder in classical and quantum systems with works showing the existence of novel disordered phases such as the Bose glass and the Bragg glass. He is the author of about 300 publications and one monograph "Quantum physics in one dimension" with Oxford. Since 2013 he has been a member of the French Academy of Sciences, and a fellow of the American Physical Society.