Regensburg 2025 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 2: Nonequilibrium Quantum Systems (joint session TT/DY)
DY 2.11: Talk
Monday, March 17, 2025, 12:15–12:30, H31
Visualizing dynamics of charges and strings in (2+1)D lattice gauge theories — Tyler A. Cochran1,2, •Bernhard Jobst3,4, Eliott Rosenberg1, Yuri D. Lensky1, Adam Gammon-Smith5, Michael Knap3,4, Frank Pollmann3,4, and Pedram Roushan1 — 1Google Research, CA, USA — 2Princeton University, NJ, USA — 3Technical University of Munich, 85748 Garching, Germany — 4MCQST, 80799 München, Germany — 5University of Nottingham, NG7 2RD, UK
Lattice gauge theories (LGTs) can be employed to understand a wide range of phenomena. Studying their dynamical properties can be challenging as it requires solving many-body problems that are generally beyond perturbative limits. We investigate the dynamics of local excitations in a Z2 LGT using a two-dimensional lattice of superconducting qubits. We first construct a simple variational circuit which prepares low-energy states that have a large overlap with the ground state; then we create particles with local gates and simulate their quantum dynamics via a discretized time evolution. As the effective magnetic field is increased, our measurements show signatures of transitioning from deconfined to confined dynamics. For confined excitations, the magnetic field induces a tension in the string connecting them. Our method allows us to experimentally image string dynamics in a (2+1)D LGT from which we uncover two distinct regimes inside the confining phase: for weak confinement the string fluctuates strongly in the transverse direction, while for strong confinement transverse fluctuations are effectively frozen.
Keywords: Quantum Computing; Quantum Simulation; Lattice Gauge Theory