Adiabatic dynamics in a spin-1 chain with uniaxial single-spin anisotropy

TL;DR

This paper investigates the non-equilibrium adiabatic quantum dynamics of a spin-1 XY chain with uniaxial anisotropy, revealing complex scaling behavior during a quench across a critical line.

Contribution

It demonstrates that the excess energy scaling during a quench is non-trivial due to competing effects of low-lying excited states across a critical line.

Findings

Excess energy exhibits unique scaling behavior not explained by standard Kibble-Zurek theory.

Large system sizes reveal complex dynamics influenced by a continuum of critical points.

The study highlights the importance of critical lines in quantum phase transition dynamics.

Abstract

We study the adiabatic quantum dynamics of an anisotropic spin-1 XY chain across a second order quantum phase transition. The system is driven out of equilibrium by performing a quench on the uniaxial single-spin anisotropy, that is supposed to vary linearly in time. We show that, for sufficiently large system sizes, the excess energy after the quench admits a non trivial scaling behavior that is not predictable by standard Kibble-Zurek arguments for isolated critical points or extended critical regions. This emerges from a competing effect of many accessible low-lying excited states, inside the whole continuous line of critical points.