Entanglement generation of arbitrary squeezed Fock states

TL;DR

This paper presents a robust protocol for generating entanglement between a superconducting qubit and a squeezed cavity using a parametric drive, effective high-order processes, and adiabatic tuning, confirmed by numerical simulations.

Contribution

It introduces a new method for creating complex non-Gaussian entangled states in superconducting systems with high fidelity and robustness.

Findings

High-fidelity entanglement between qubit and squeezed cavity achieved.

Analytical resonance conditions derived for high-order three-photon processes.

Numerical simulations confirm robustness and practicality of the protocol.

Abstract

We propose an efficient and robust protocol for the generation of entanglement between a superconducting qubit and a squeezed cavity. By applying a parametric drive to the cavity coupled to the qubit, the dynamical evolution of the system is precisely described by an anisotropic Rabi model within a squeezed reference frame. Utilizing high-order time-averaging methods, we analytically derive the resonance conditions and the effective Rabi frequency for the high-order three-photon process. By implementing an adiabatic passage, slowly tuning the cavity frequency across the resonance, the system is steered into a maximally entangled state, e.g., between the three-photon state $\ket{g,3}$ and the qubit excited state $\ket{e,0}$ in the squeezed picture. Numerical simulation results confirm the high fidelity and robustness of the proposed protocol. Our method provides a practical pathway for generating complex non-Gaussian entangled states, which are of significant value for fault-tolerant quantum computation and quantum metrology beyond the standard quantum limit.