Nonequilibrium phases in hybrid arrays with flux qubits and NV centers

TL;DR

This paper proposes a hybrid quantum system combining flux qubits and NV centers to simulate localization-delocalization transitions, enabling experimental observation and control of quantum phase changes in a Jaynes-Cummings-lattice framework.

Contribution

It introduces a novel hybrid architecture with qubit-mediated interactions for studying phase transitions, distinct from traditional cavity-coupled arrays.

Findings

Demonstrates the feasibility of monitoring phase transitions non-equilibrium scenarios.

Shows the system can be tuned in-situ for different coupling regimes.

Highlights advantages over cavity-based lattices in dimensionality and control.

Abstract

We propose a startling hybrid quantum architecture for simulating a localization-delocalization transition. The concept is based on an array of superconducting flux qubits which are coupled to a diamond crystal containing nitrogen-vacancy (NV) centers. The underlying description is a Jaynes-Cummings-lattice in the strong-coupling regime. However, in contrast to well-studied coupled cavity arrays the interaction between lattice sites is mediated here by the qubit rather than by the oscillator degrees of freedom. Nevertheless, we point out that a transition between a localized and a delocalized phase occurs in this system as well. We demonstrate the possibility of monitoring this transition in a non-equilibrium scenario, including decoherence effects. The proposed scheme allows the monitoring of localization-delocalization transitions in Jaynes-Cummings-lattices by use of currently available experimental technology. Contrary to cavity-coupled lattices, our proposed recourse to stylized qubit networks facilitates (i) to investigate localization-delocalization transitions in arbitrary dimensions and (ii) to tune the inter-site coupling in-situ.