Thermalization dynamics of a gauge theory on a quantum simulator

• Published in: Science (American Association for the Advancement of Science) Vol. 377; no. 6603; pp. 311 - 314
• Main Authors: Zhou, Zhao-Yu, Su, Guo-Xian, Halimeh, Jad C., Ott, Robert, Sun, Hui, Hauke, Philipp, Yang, Bing, Yuan, Zhen-Sheng, Berges, Jürgen, Pan, Jian-Wei
• Format: Journal Article
• Language: English
• Published: Washington The American Association for the Advancement of Science 15-07-2022
• Subjects: Computers; Evolution; Gauge theory; Optical lattices; Simulation; Symmetry; System effectiveness; Thermalization (energy absorption)
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.abl6277

Gauge theories form the foundation of modern physics, with applications ranging from elementary particle physics and early-universe cosmology to condensed matter systems. We perform quantum simulations of the unitary dynamics of a U(1) symmetric gauge field theory and demonstrate emergent irreversible behavior. The highly constrained gauge theory dynamics are encoded in a one-dimensional Bose-Hubbard simulator, which couples fermionic matter fields through dynamical gauge fields. We investigated global quantum quenches and the equilibration to a steady state well approximated by a thermal ensemble. Our work may enable the investigation of elusive phenomena, such as Schwinger pair production and string breaking, and paves the way for simulating more complex, higher-dimensional gauge theories on quantum synthetic matter devices.
Simulating thermalization dynamics
Calculating the dynamics of gauge theories, which underlie some of the most successful models in physics, is extremely challenging for classical computers. An alternative to computation is quantum simulation using tunable physical systems in which gauge symmetry constraints can be effectively implemented. Zhou
et al
. studied the thermalization of a U(1)-symmetric gauge theory using cold bosonic atoms trapped in a tilted staggered optical lattice. The system’s evolution depended on whether the gauge constraint was enforced. Additionally, different gauge-symmetric initial states with the same energy density evolved to the same thermal state. —JS
Cold bosonic atoms trapped in a tilted staggered optical lattice were used to simulate the dynamics of a gauge theory.