Quantum steering ellipsoids and quantum obesity in critical systems

TL;DR

This paper introduces quantum obesity as a new measure of quantum correlations, demonstrating its effectiveness in detecting quantum phase transitions and how local filtering can enhance its critical behavior.

Contribution

It presents quantum obesity as a novel, analytically computable quantum correlation measure and establishes its role in identifying quantum critical phenomena.

Findings

Quantum obesity detects quantum phase transitions.

Local filtering amplifies QO near critical points.

QO changes under local operations are characterized by a new theorem.

Abstract

Quantum obesity (QO) is new function used to quantify quantum correlations beyond entanglement, which also works as a witness for entanglement. Thanks to its analyticity for arbitrary state of bipartite systems, it represents an advantage with respect to other quantum correlations, like quantum discord for example. In this work we show that QO is a fundamental quantity to observe signature of quantum phase transitions. We also describe a mechanism based on local filtering operations able to intensify the critical behavior of the QO near to the transition point. To this end, we introduce a theorem stating how QO changes under local quantum operations and classical communications. This work opens perspective for the characterization of new phenomena in quantum critical systems through the analytically computable pairwise QO.