6533b86ffe1ef96bd12cd2c2
RESEARCH PRODUCT
Relaxation of the order-parameter statistics and dynamical confinement
Pasquale CalabresePasquale CalabreseRiccardo Javier Valencia TortoraMario Collurasubject
Field (physics)Phase (waves)General Physics and AstronomyFOS: Physical sciences0501 natural sciences010305 fluids & plasmasParamagnetismMagnetization0103 physical sciences010306 general physicsCondensed Matter - Statistical MechanicsPhysicsQuantum Physics50SpinsCondensed matter physics30Statistical Mechanics (cond-mat.stat-mech)-dTime evolution+qSettore FIS/02 - Fisica Teorica Modelli e Metodi MatematiciThermalisation05 30 -d 05 50 +qRelaxation (physics)Quantum Physics (quant-ph)description
We study the relaxation of the local ferromagnetic order in the quantum Ising chain in a slant field with both longitudinal and transverse components. After preparing the system in a fully polarised state, we analyse the time evolution of the entire probability distribution function (PDF) of the magnetisation within a block of $\ell$ spins. We first analyse the effect of confinement on the gaussification of the PDF for large $\ell$, showing that the melting of initial order is suppressed when the longitudinal field is aligned to initial magnetisation while it is sped up when it is in the opposite direction. Then we study the thermalisation dynamics. In the paramagnetic region, the PDF quickly shows thermal features. Conversely, in the ferromagnetic phase, when confinement takes place, the relaxation suffers a typical slowing down which depends on the interplay between the strength of the longitudinal field, the density of excitations, and the direction of the initial polarisation. Even when the initial magnetisation is aligned oppositely to the longitudinal field, confinement prevents thermalisation in the accessible timescale, as it is neatly bared by the PDF.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2020-01-01 | EPL (Europhysics Letters) |