R. G. Herb Condensed Matter Seminars |
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Events During the Week of March 6th through March 13th, 2022
Monday, March 7th, 2022
- No events scheduled
Tuesday, March 8th, 2022
- Simulating quantum many-body phenomena with superconducting qubits
- Time: 10:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Roman Kuzmin, University of Maryland
- Abstract: Superconducting circuits are ubiquitous in quantum simulations, computing, and metrology. In this talk, I will show a superconducting circuit platform extended to the extreme, in which the circuits actually become insulating. Remarkably, such nominally insulating circuits are a valuable resource. They create a tunable high-impedance environment and facilitate exceptionally strong interactions between photons and superconducting qubits. This opens up new directions for analog quantum simulations of interacting many-body problems, with examples ranging from quantum phase transitions to many-body localization. In particular, I will start with the demonstration of a dissipative quantum phase transition in a Josephson junction facing an Ohmic environment. Despite many experimental attempts, the existence of such a transition remains controversial. Using the high-impedance circuit environment, I will present evidence of the transition with a conceptually new approach, which relies on monitoring environmental degrees of freedom. A similar approach applies to analog quantum simulations of other strongly interacting models, which I will illustrate on two quantum impurity models relevant to the physics of Luttinger liquids and the Kondo effect. In the latter case, interactions induced by a quantum impurity in a finite size system allow us to observe the phenomenon of many-body localization. Finally, I will argue that the high-impedance circuit platform can contribute to the development of various areas of quantum science and technology.
- Host: Mark Saffman
Wednesday, March 9th, 2022
- No events scheduled
Thursday, March 10th, 2022
- Skyrmion pairing: a topological route to superconductivity
- Time: 10:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Shubhayu Chatterjee, University of California Berkeley
- Abstract: Atomically thin Van der Waals materials have emerged as a highly versatile platform to advance our understanding of quantum matter driven by strong electron correlations. Recent experimental breakthroughs in stabilizing few-layered graphene structures with a “magic” relative twist between layers has led to the discovery of a wide variety of correlated states ranging from magnetism to superconductivity. Despite compelling experimental evidence for unconventional superconductivity, the glue which binds electrons into Cooper pairs remains a mystery. In this talk I will propose a novel resolution: the Cooper pairs are composed of electrically charged topological spin textures called “skyrmions,” rather than electrons. First proposed by Tony Skyrme to model baryons in particle physics, I will explain how their topological properties can give rise to superconductivity in an electronic model with purely repulsive interactions, and without recourse to phonons which are conventionally responsible for pairing.
- Host: Robert McDermott
Friday, March 11th, 2022
- No events scheduled