Adiabatic freezing of long-range quantum correlations in spin chains

TL;DR

This paper introduces a phenomenon called adiabatic freezing, where long-range quantum discord between end spins in a spin chain remains stable under slow parameter changes, with implications for quantum sensing and simulation.

Contribution

It demonstrates the adiabatic freezing of quantum correlations in spin chains, showing robustness to thermal fluctuations and potential for experimental realization.

Findings

Quantum discord between end spins remains frozen under adiabatic variations.

Freezing interval can detect anisotropy transitions in XY spin chains.

Energy gap remains frozen during adiabatic parameter changes.

Abstract

We consider a process to create quasi long-range quantum discord between the non-interacting end spins of a quantum spin chain, with the end spins weakly coupled to the bulk of the chain. The process is not only capable of creating long-range quantum correlation but the latter remains frozen, when certain weak end-couplings are adiabatically varied below certain thresholds. We term this phenomenon as adiabatic freezing of quantum correlation. We observe that the freezing is robust to moderate thermal fluctuations and is intrinsically related to the cooperative properties of the quantum spin chain. In particular, we find that the energy gap of the system remains frozen for these adiabatic variations, and moreover, considering the end spins as probes, we show that the interval of freezing can detect the anisotropy transition in quantum XY spin chains. Importantly, the adiabatic freezing of long-range quantum correlations can be simulated with contemporary experimental techniques.