Quantum phase transition of nonlocal Ising chain with transverse field in a resonator

TL;DR

This paper investigates quantum phase transitions in a complex spin chain coupled to a resonator, revealing super-radiant phase transitions and diverse magnetic phases influenced by the resonator field.

Contribution

It introduces a model of a nonlocal Ising chain with position-dependent coupling to a resonator, demonstrating controllable super-radiant phase transitions and rich magnetic phase behavior.

Findings

Super-radiant phase transition occurs at strong qubit-resonator coupling.

Selective mode transition achieved by modulating Ising interaction.

Resonator field significantly alters magnetic properties and correlations.

Abstract

We study the quantum phase transition in a spin chain with variable Ising interaction and position-dependent coupling to a resonator field. Such a complicated model, usually not present in natural physical systems, can be simulated by an array of qubits based on man-made devices and exhibits interesting behavior. We show that, when the coupling between the qubit and field is strong enough, a super-radiant phase transition occurs, and it is possible to pick a particular field mode to undergo this phase transition by properly modulating the strength of the Ising interaction. We also study the impact of the resonator field on the magnetic properties of the spin chain, and find a rich set of phases characterized by distinctive qubit correlation functions.