Autonomous Stabilization of Fock States in an Oscillator against Multiphoton Losses

TL;DR

This paper presents an experimental method to autonomously stabilize multi-photon Fock states in a superconducting circuit, effectively counteracting multi-photon losses and enabling error correction in quantum information processing.

Contribution

The authors develop and demonstrate a cascaded photon-addition dissipation engineering technique that stabilizes Fock states against multiple photon losses in a superconducting circuit.

Findings

Prolonged preservation of nonclassical Wigner negativities for Fock states N=1,2,3.

Effective stabilization of multi-photon Fock states for about 10 ms.

Implementation of a non-unitary reset operation for binomially-encoded qubits.

Abstract

Fock states with a well-defined number of photons in an oscillator have shown a wide range of applications in quantum information science. Nonetheless, their usefulness has been marred by single and multiple photon losses due to unavoidable environment-induced dissipation. Though several dissipation engineering methods have been developed to counteract the leading single-photon loss error, averting multiple photon losses remains elusive. Here, we experimentally demonstrate a dissipation engineering method that autonomously stabilizes multi-photon Fock states against losses of multiple photons using a cascaded selective photon-addition operation in a superconducting quantum circuit. Through measuring the photon-number populations and Wigner tomography of the oscillator states, we observe a prolonged preservation of nonclassical Wigner negativities for the stabilized Fock states $\vert N\rangle$ with $N=1,2,3$ for a duration of about 10 ms. Furthermore, the dissipation engineering method demonstrated here also facilitates the implementation of a non-unitary operation for resetting a binomially-encoded logical qubit. These results highlight potential applications in error-correctable quantum information processing against multi-photon-loss errors.