Generation of time-frequency entangled photon pairs propagating in separate waveguides in circuit QED setup

TL;DR

This paper proposes a cavity QED setup for on-demand generation of time-frequency entangled photon pairs in separate waveguides, with potential implementation in superconducting circuits, and analyzes their entanglement properties.

Contribution

It introduces a generic cavity QED scheme for generating entangled photon pairs with detailed theoretical modeling and potential practical implementation in circuit QED systems.

Findings

Numerical solutions of the system's equations of motion reveal photon emission dynamics.

Entanglement entropy depends on system parameters, indicating tunability.

Potential extension to multiphoton entangled state generation.

Abstract

Time-frequency entangled photons constitute an important resource for a plethora of applications across the diverse quantum technology landscape. Thus, efficient and tunable setups for the generation of entangled photons are requisite for modern quantum technologies. In this work, we propose a generic cavity QED setup designed for on-demand generation of time-frequency entangled photon pairs, with each photon propagating in a separate waveguide. We outline a potential incarnation of this setup in the microwave superconducting circuit QED architecture. We derive and numerically solve the set of equations of motion governing the evolution of the quantum state of the system, allowing us to examine the photon emission dynamics. Using the Schmidt decomposition of the joint spectral amplitude of the emitted photon pair, we compute the entanglement entropy analyzing its dependence on the system parameters. We outline the potential extension of the proposed scheme for the generation of multiphoton time-frequency entangled states.