Rabi-like oscillations of an anharmonic oscillator: classical or quantum effect?

Julien Claudon (1) , Alex Zazunov (2) , Frank. W. J. Hekking (2) , Olivier Buisson (3)

1 NPSC - Nanophysique et Semiconducteurs
2 LPM2C - Laboratoire de physique et modélisation des milieux condensés
3 NEEL - QuantECA - Circuits électroniques quantiques Alpes

We have observed Rabi-like oscillations in a current-biased dc SQUID presenting enhanced coherence times compared to our previous realization [Claudon_PRL93,187003(2004)). This Josephson device behaves as an anharmonic oscillator which can be driven into a coherent superposition of quantum states by resonant microwave ($\mu$w) flux pulses. At large $\mu$w amplitude, the superposition involves many levels, and the system behaves classically. When the amplitude is reduced, a crossover region is found between this classical dynamics and a quantum two-level behavior. This intermediate regime involves a few levels and is fully explained by a quantum model, whereas a classical approach fails to describe the experimental data.

Mots clés: Quantum dynamics; superconducting quantum circuits; Rabi oscillation; quantum anharmonic oscillator; superconducting qubits

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Julien Claudon, Alex Zazunov, Frank. W. J. Hekking, Olivier Buisson. Rabi-like oscillations of an anharmonic oscillator: classical or quantum effect?. 2007. ⟨hal-00174630v1⟩