# Interfering pathways for photon blockade in cavity QED with one and two qubits

## TL;DR

This paper theoretically investigates quantum interference effects leading to photon blockade in cavity QED systems with one or two atoms, revealing conditions for antibunched photon generation independent of system parameters.

## Contribution

It identifies specific conditions under which quantum interference induces photon blockade in single and two-atom cavity QED systems, including new pathways and parameter independence.

## Key findings

- Cavity-driven systems can exhibit photon blockade due to quantum interference.
- Atom-driven systems do not show interference-induced photon blockade unless additional pathways are present.
- Photon blockade can be achieved in both weak and strong coupling regimes independently of system parameters.

## Abstract

We theoretically study the quantum interference induced photon blockade phenomenon in atom cavity QED system, where the destructive interference between two different transition pathways prohibits the two-photon excitation. Here, we first explore the single atom cavity QED system via an atom or cavity drive. We show that the cavity-driven case will lead to the quantum interference induced photon blockade under a specific condition, but the atom driven case can't result in such interference induced photon blockade. Then, we investigate the two atoms case, and find that an additional transition pathway appears in the atom-driven case. We show that this additional transition pathway results in the quantum interference induced photon blockade only if the atomic resonant frequency is different from the cavity mode frequency. Moreover, in this case, the condition for realizing the interference induced photon blockade is independent of the system's intrinsic parameters, which can be used to generate antibunched photon source both in weak and strong coupling regimes.