Non-equilibrium steady states in quantum critical systems with Lifshitz scaling

• Main Authors: Daniel Fernández, Aruna Rajagopal, Lárus Thorlacius
• Format: Article
• Language: English
• Published: SpringerOpen 2019-12-01
• Series: Journal of High Energy Physics
• Subjects: Effective Field Theories; Space-Time Symmetries; Quantum Dissipative Sys- tems
• Online Access: https://doi.org/10.1007/JHEP12(2019)115

Abstract We study out-of-equilibrium energy transport in a quantum critical fluid with Lifshitz scaling symmetry following a local quench between two semi-infinite fluid reservoirs. The late time energy flow is universal and is accommodated via a steady state occupying an expanding central region between outgoing shock and rarefaction waves. We consider the admissibility and entropy conditions for the formation of such a non-equilibrium steady state for a general dynamical critical exponent z in arbitrary dimensions and solve the associated Riemann problem. The Lifshitz fluid with z = 2 can be obtained from a Galilean boost invariant field theory and the non-equilibrium steady state is identified as a boosted thermal state. A Lifshitz fluid with generic z is scale invariant but without boost symmetry and in this case the non-equilibrium steady state is genuinely non-thermal.