Locally quasi-stationary states in noninteracting spin chains
Maurizio Fagotti
Abstract
Locally quasi-stationary states (LQSS) were introduced as inhomogeneous generalisations of stationary states in integrable systems. Roughly speaking, LQSSs look like stationary states, but only locally. Despite their key role in hydrodynamic descriptions, an unambiguous definition of LQSSs was not given. By solving the dynamics in inhomogeneous noninteracting spin chains, we identify the set of LQSSs as a subspace that is invariant under time evolution, and we explicitly construct the latter in a generalised XY model. As a by-product, we exhibit an exact generalised hydrodynamic theory (including ``quantum corrections'').
Topics & Concepts
Stationary stateIntegrable systemSubspace topologyPhysicsInvariant (physics)Spin (aerodynamics)Statistical physicsProduct (mathematics)Quantum mechanicsTheoretical physicsMathematical physicsMathematicsMathematical analysisGeometryThermodynamicsQuantum many-body systemsAlgebraic structures and combinatorial modelsSpectroscopy and Quantum Chemical Studies