QUROPE Quantum Information Processing and Communication in Europe

Superconducting circuits based on Josephson junctions are among the most promising solid state candidates for implementing quantum computing algorithms. Although no efficient superconducting quantum processor has yet been operated since the first demonstration in 1999 of quantum coherence in the Cooper pair box circuit, significant progress has been achieved in terms of quantum coherence, readout fidelity, gate operation and circuit complexity.

Superconducting circuits based on Josephson junctions are among the most promising solid state candidates for implementing quantum computing algorithms. Although no efficient superconducting quantum processor has yet been operated since the first demonstration in 1999 of quantum coherence in the Cooper pair box circuit, significant progress has been achieved in terms of quantum coherence, readout fidelity, gate operation and circuit complexity.

We report the realization of a quantum circuit in which an ensemble of electronic spins is coupled to a frequency tunable superconducting resonator. The spins are Nitrogen-Vacancy centers in a diamond crystal. The achievement of strong coupling is manifested by the appearance of a vacuum Rabi splitting in the transmission spectrum of the resonator when its frequency is tuned through the NV center electron spin resonance. 

We report the realization of a quantum circuit in which an ensemble of electronic spins is coupled to a frequency tunable superconducting resonator. The spins are Nitrogen-Vacancy centers in a diamond crystal. The achievement of strong coupling is manifested by the appearance of a vacuum Rabi splitting in the transmission spectrum of the resonator when its frequency is tuned through the NV center electron spin resonance. 

We report the realization of a quantum circuit in which an ensemble of electronic spins is coupled to a frequency tunable superconducting resonator. The spins are Nitrogen-Vacancy centers in a diamond crystal. The achievement of strong coupling is manifested by the appearance of a vacuum Rabi splitting in the transmission spectrum of the resonator when its frequency is tuned through the NV center electron spin resonance. 

We report the realization of a quantum circuit in which an ensemble of electronic spins is coupled to a frequency tunable superconducting resonator. The spins are Nitrogen-Vacancy centers in a diamond crystal. The achievement of strong coupling is manifested by the appearance of a vacuum Rabi splitting in the transmission spectrum of the resonator when its frequency is tuned through the NV center electron spin resonance. 

Bridging the gap between quantum-optical and solid-state implementations of quantum information is currently one of the major challenges in the field. Microscopic quantum systems have long coherence times, whereas artificial superconducting atoms can be manipulated and entangled very rapidly and with high fidelity; it is therefore appealing to combine them to form “hybrid” quantum circuits. In a first set of experiments towards this goal, we have demonstrated the strong coupling between an ensemble of electronic spins and a frequency tunable superconducting resonator [1].