Slowing quantum decoherence of oscillators by hybrid processing

TL;DR

This paper introduces a hybrid protection scheme using ancillas to slow quantum decoherence in superpositions of coherent states, enhancing robustness against loss in various quantum systems.

Contribution

It proposes a deterministic hybrid method with two-level ancillas to protect macroscopic quantum coherence from decoherence and loss.

Findings

Robustness of the scheme against qubit dephasing.

Enhanced loss robustness with larger coherent state amplitudes.

Feasible implementation in atoms, solid-state, and superconducting circuits.

Abstract

Quantum information encoded into superposition of coherent states is an illustrative representative of practical applications of macroscopic quantum coherence possessing. However, these states are very sensitive to energy loss, losing their non-classical aspects of coherence very rapidly. An available deterministic strategy to slow down this decoherence process is to apply a Gaussian squeezing transformation prior to the loss as a protective step. Here, we propose a deterministic hybrid protection scheme utilizing strong but feasible interactions with two-level ancillas immune to spontaneous emission. We verify robustness of the scheme against dephasing of qubit ancilla. Our scheme is applicable to complex superpositions of coherent states in many oscillators, and remarkably, the robustness to loss is enhanced with the amplitude of the coherent states. This scheme can be realized in experiments with atoms, solid-state systems and superconducting circuits.