Probing dynamics in quantum simulators

Abstract: In this talk I will discuss new possibilities to probe the dynamics of quantum many-body systems, in particular the Bose-Hubbard model with and without disorder. Out-of-time-ordered (OTO) correlation functions have been proposed to describe the distribution or “scrambling” of information across a quantum state. We investigate both time-ordered and OTO correlation functions in the non-integrable, one-dimensional Bose-Hubbard model at high temperatures where well-defined quasiparticles cease to exist. We propose an interferometric scheme to approach the challenge of measuring these correlation functions in real space and time. Performing numerical simulations based on matrix product operators, we observe a linear light-cone spreading of quantum information in the OTO correlators. In contrast with the fast spreading of information, the thermalization of the system takes parametrically longer due to the slow diffusion of conserved quantities. Adding strong disorder can inhibit thermalization, leading to a many-body localized (MBL) phase. Beyond the absence of transport, the MBL phase has distinctive signatures, such as slow dephasing and logarithmic entanglement growth. We experimentally probe these signatures in a system of coupled superconducting qubits.

condensed matterchaotic dynamicsexactly solvable and integrable systemsquantum physics

Audience: researchers in the topic

Quantum Chaos 2020 Seminars

Series comments: A series of online talks about topics related to Quantum Chaos in its various forms, including (but not limiting to): Manifestations of chaos in quantum systems, quantum information scrambling, ergodicity and thermalization in closed many-body quantum systems, and quantum simulations of complex quantum dynamics .

Talks given by senior researchers as well as students and postdocs.