Antibunched <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>N</mml:mi></mml:math>-photon bundles emitted by a Josephson photonic device
Sheng-li Ma, Xinke Li, Ya-long Ren, Ji-kun Xie, Fuli Li
Abstract
We propose an experimentally feasible scheme for generating antibunched $N$-photon bundles by a dc voltage-biased Josephson junction in series with a superconducting microwave resonator and a charge qubit. Each resonant tunneling Cooper pair leads to the excitation of the charge qubit and resonator with $N$ photons simultaneously via the ac Josephson effect. Meanwhile, the charge qubit with strong anharmonicity is utilized to regulate the tunneling behavior of the Cooper pairs; that is, the presence of $N$ photons in the resonator prevents the next tunnel event. So the resonator contains only $N$ photons or none, and all other possibilities are greatly suppressed. Combined with the system's dissipation, the resonator can emit its energy in antibunched bundles of $N$ strongly correlated photons with high purity and an in situ tunable emission rate. Such a nonclassical source could be useful in applications in the field of quantum information science.