Field locked to Fock state by quantum feedback with single photon corrections

TL;DR

This paper demonstrates a quantum feedback method that prepares and stabilizes specific Fock states in a microwave cavity, using Rydberg atoms for non-demolition sensing and photon correction, enabling on-demand quantum state control.

Contribution

It introduces a novel quantum feedback technique that corrects single-photon jumps, allowing deterministic preparation and stabilization of Fock states up to n=7 in a superconducting cavity.

Findings

Successfully prepared Fock states up to n=7

Implemented real-time correction of quantum jumps

Achieved flexible generation of arbitrary Fock state sequences

Abstract

Fock states with photon numbers n up to 7 are prepared on demand in a microwave superconducting cavity by a quantum feedback procedure which reverses decoherence-induced quantum jumps. Circular Rydberg atoms are used as quantum non-demolition sensors or as single photon emitter/absorber actuators. The quantum nature of these actuators matches the correction of single-photon quantum jumps due to relaxation. The flexibility of this method is suited to the generation of arbitrary sequences of Fock states.