Single-qubit lasing and cooling at the Rabi frequency

TL;DR

This paper explores novel quantum optics phenomena in a superconducting qubit coupled to an oscillator, demonstrating lasing and cooling effects at the Rabi frequency, including a single-atom-two-photon laser at the symmetry point.

Contribution

It introduces the first analysis of Rabi-frequency resonance effects in a qubit-oscillator system, revealing new lasing and cooling regimes and a single-atom-two-photon laser.

Findings

Blue detuning induces population inversion and bi-stability with lasing.

Red detuning results in cooling of the oscillator.

Effects persist at the symmetry point with minimized decoherence.

Abstract

For a superconducting qubit driven to perform Rabi oscillations and coupled to a slow electromagnetic or nano-mechanical oscillator we describe previously unexplored quantum optics effects. When the Rabi frequency is tuned to resonance with the oscillator the latter can be driven far from equilibrium. Blue detuned driving leads to a population inversion in the qubit and a bi-stability with lasing behavior of the oscillator; for red detuning the qubit cools the oscillator. This behavior persists at the symmetry point where the qubit-oscillator coupling is quadratic and decoherence effects are minimized. There the system realizes a "single-atom-two-photon laser".