Quantum thermodynamics for lattice gauge theories

Nicole Yunger Halpern (NIST, QuICS and University of Maryland) examines how to describe nonequilibrium matter in the early universe and particle colliders from the Standard Model. Classical lattice-gauge calculations have limited reach, motivating quantum simulation. Local Gauss-law constraints create an intricate Hilbert-space structure that complicates thermodynamic definitions for systems coupled to reservoirs, both at equilibrium and during nonequilibrium processes.

The talk develops definitions of work and heat through strong-coupling thermodynamics, applying them to instantaneous quenches that quantum simulators can implement. A Z2 lattice gauge theory coupled to matter in one spatial and one temporal dimension provides the example: computed work and heat vary with the quench parameter and reveal the expected phase transition. The framework connects gauge constraints, reservoir coupling and experimentally relevant thermodynamic quantities.