The coset construction for nonequilibrium systems
Abstract
We propose a systematic coset construction of nonequilibrium effective field theories (EFTs) governing the longdistance and latetime dynamics of relativistic, finitetemperature condensed matter systems. Our nonequilibrium coset construction makes significant advances beyond more standard coset constructions in that it takes advantage of recentlydeveloped techniques, which allow the formulation of nonequilibrium effective actions that account for quantum and thermal fluctuations as well as dissipation. Because these systems exist at finite temperature, the EFTs live on the closedtimepath of the SchwingerKeldysh contour. Since the coset construction and the nonequilibrium effective actions may be unfamiliar to many readers, we include brief introductions to these topics in an effort to make this paper selfcontained. To demonstrate the legitimacy of this coset construction, we successfully reproduce the known EFTs for fluids and superfluids at finite temperature. Then, to demonstrate its utility, we construct novel EFTs for solids, supersolids, and four phases of liquid crystals, all at finite temperature. We thereby combine the nonequilibrium effective action and the coset construction to create a powerful tool that can be used to study manybody systems out of thermal equilibrium.
 Publication:

Journal of High Energy Physics
 Pub Date:
 July 2020
 DOI:
 10.1007/JHEP07(2020)200
 arXiv:
 arXiv:1912.12301
 Bibcode:
 2020JHEP...07..200L
 Keywords:

 Effective Field Theories;
 Quantum Dissipative Systems;
 Thermal Field Theory;
 High Energy Physics  Theory;
 Condensed Matter  Other Condensed Matter;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology
 EPrint:
 42 pages, 1 figure. Reflects published version