Wisconsin Quantum Institute

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Simulating quantum many-body phenomena with superconducting qubits
Date: Tuesday, March 8th
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
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