Superconducting Resonator-Rydberg Atom Hybrid in the Strong Coupling Regime

TL;DR

This paper proposes a hybrid quantum system combining a Rydberg atom and a superconducting resonator, demonstrating strong coupling and potential for quantum information processing.

Contribution

It introduces a novel hybrid system with tunable atom-resonator interaction and large cooperativity, enabling advanced quantum gate operations.

Findings

Achieved strong atom-resonator coupling with high cooperativity.

Demonstrated the ability to perform universal two-qubit gates.

Showed potential for cavity-mediated quantum state transmission.

Abstract

We propose a promising hybrid quantum system, where a highly-excited atom strongly interacts with a superconducting LC oscillator via the electric field of capacitor. An external electrostatic field is applied to tune the energy spectrum of atom. The atomic qubit is implemented by two eigenstates near an avoided-level crossing in the DC Stark map of Rydberg atom. Varying the electrostatic field brings the atomic-qubit transition on- or off-resonance to the microwave resonator, leading to a strong atom-resonator coupling with an extremely large cooperativity. Like the nonlinearity induced by Josephson junctions in superconducting circuits, the large atom-resonator interface disturbs the harmonic potential of resonator, resulting in an artificial two-level particle. Different universal two-qubit logic gates can also be performed on our hybrid system within the space where an atomic qubit couples to a single photon with an interaction strength much larger than any relaxation rates, opening the door to the cavity-mediated state transmission.