Density-functional fidelity approach to quantum phase transitions

TL;DR

This paper introduces a density-functional fidelity method to identify quantum phase transitions by comparing ground state densities, which can be experimentally measured and is validated on specific models.

Contribution

It presents a novel, experimentally accessible approach to detect quantum phase transitions using density-functional fidelity, validated on the Lipkin-Meshkov-Glick and Hubbard models.

Findings

Density-functional fidelity effectively signals quantum phase transitions.

The method is experimentally feasible for measuring ground state similarities.

Validated on models demonstrating its broad applicability.

Abstract

We propose a new approach to quantum phase transitions in terms of the density-functional fidelity, which measures the similarity between density distributions of two ground states in parameter space. The key feature of the approach, as we will show, is that the density-functional fidelity can be measured easily in experiments. Both the validity and versatility of the approach are checked by the Lipkin-Meshkov-Glick model and the one-dimensional Hubbard model.