Parity-dependent State Engineering and Tomography in the ultrastrong coupling regime.

S Felicetti,G Romero,P Milman,E Solano,T Douce

doi:10.1038/srep11818

Abstract

Reaching the strong coupling regime of light-matter interaction has led to an impressive development in fundamental quantum physics and applications to quantum information processing. Latests advances in different quantum technologies, like superconducting circuits or semiconductor quantum wells, show that the ultrastrong coupling regime (USC) can also be achieved, where novel physical phenomena and potential computational benefits have been predicted. Nevertheless, the lack of effective decoupling mechanism in this regime has so far hindered control and measurement processes. Here, we propose a method based on parity symmetry conservation that allows for the generation and reconstruction of arbitrary states in the ultrastrong coupling regime of light-matter interactions. Our protocol requires minimal external resources by making use of the coupling between the USC system and an ancillary two-level quantum system.

Highlights

The realization of platforms composed of effective two-level quantum systems interacting with the discrete electromagnetic modes of a resonator represents a milestone in the history of quantum physics
We have analyzed the interaction between an ancillary qubit and an ultrastrongly coupled qubit-cavity system
We find that the presence of a ultrastrong coupling regime (USC) qubit-cavity system modifies the interaction of the cavity with the ancillary qubit in a nontrivial manner

Summary

Introduction

The realization of platforms composed of effective two-level quantum systems interacting with the discrete electromagnetic modes of a resonator represents a milestone in the history of quantum physics. Interacts with the cavity mode in the USC regime, forming polariton states, while the coupling strength of the ancillary qubit with the cavity is in the SC regime.

Results

Conclusion