# One-way quantum deficit and quantum coherence in the anisotropic $XY$ chain

## TL;DR

This paper explores how one-way quantum deficit and quantum coherence reveal quantum phase transitions in the anisotropic XY spin chain at both zero and finite temperatures, providing analytical and numerical insights.

## Contribution

It introduces the use of one-way quantum deficit as a tool to characterize quantum phase transitions and coherence in the XY model, including analytical expressions at zero temperature.

## Key findings

- Quantum deficit signals phase transition at λ=1
- Quantum coherence aligns with quantum deficit at zero temperature
- Finite temperature effects are also analyzed

## Abstract

In this study, we investigate pairwise non-classical correlations measured using a one-way quantum deficit as well as quantum coherence in the $XY$ spin-1/2 chain in a transverse magnetic field for both zero and finite temperatures. The analytical and numerical results of our investigations are presented. In the case when the temperature is zero, it is shown that the one-way quantum deficit can characterize quantum phase transitions as well as quantum coherence. We find that these measures have a clear critical point at $\lambda=1$. When $\lambda\le1$, the one-way quantum deficit has an analytical expression that coincides with the relative entropy of coherence. We also study an $XX$ model and an Ising chain at the finite temperatures.