Fidelity susceptibility as a diagnostic of the commensurate-incommensurate transition: A revisit of the programmable Rydberg chain

TL;DR

This paper uses fidelity susceptibility to analyze quantum phase transitions in programmable Rydberg chains, revealing new phases and transition behaviors influenced by Rydberg blockade effects.

Contribution

It demonstrates the effectiveness of fidelity susceptibility in diagnosing complex phase transitions in Rydberg chains, highlighting the impact of blockade radius on phase universality classes.

Findings

Transition from Potts to chiral universality class with increasing blockade radius

Emergence of a narrow floating-phase region near the phase boundary

Fidelity susceptibility as a diagnostic tool for commensurate-incommensurate transitions

Abstract

In recent years, programmable Rydberg-atom arrays have been widely used to simulate new quantum phases and phase transitions, generating great interest among theorists and experimentalists. Based on the large-scale density matrix renormalization group method, the ground-state phase diagram of one-dimensional Rydberg chains is investigated with fidelity susceptibility as an efficient diagnostic method. We find that the competition between Rydberg blockade and external detuning produces unconventional phases and phase transitions. As the Rydberg blockade radius increases, the phase transition between disordered and density-wave ordered phases changes from the standard Potts universality class to an unconventional chiral one. As the radius increases further (above Potts point but still close to the tip of the lobe), a very narrow intermediate floating-phase region begins to appear. A concise physical picture is also provided to illustrate the numerical results. Compared with previous studies, this work brings more evidence for commensurate-incommensurate quantum phase transitions in programmable quantum simulators from the perspective of quantum information, showing that fidelity susceptibility can be used to study such phase transitions.