Beyond Strong Coupling in a Massively Multimode Cavity

Abstract

The study of light-matter interaction has seen a resurgence in recent years, stimulated by highly controllable, precise, and modular experiments in cavity quantum electrodynamics (QED). The achievement of strong coupling, where the coupling between a single atom and fundamental cavity mode exceeds the decay rates, was a major milestone that opened the doors to a multitude of new investigations. Here we introduce multimode strong coupling (MMSC), where the coupling is comparable to the free spectral range (FSR) of the cavity, i.e. the rate at which a qubit can absorb a photon from the cavity is comparable to the round trip transit rate of a photon in the cavity. We realize, via the circuit QED architecture, the first experiment accessing the MMSC regime, and report remarkably widespread and structured resonance fluorescence, whose origin extends beyond cavity enhancement of sidebands. Our results capture complex multimode, multiphoton processes, and the emergence of ultranarrow linewidths. Beyond the novel phenomena presented here, MMSC opens a major new direction in the exploration of light-matter interactions.

14 pages, 11 figures. References added, typos corrected

References in corpus (10)

• Charge insensitive qubit design derived from the Cooper pair box
• Beyond the Jaynes-Cummings model: circuit QED in the ultrastrong coupling regime
• Observation of the Bloch-Siegert Shift in a Qubit-Oscillator System in the Ultrastrong Coupling Regime
• Controlling the spontaneous emission of a superconducting transmon qubit
• Ultra-Strong Light-Matter Coupling Regime with Polariton Dots
• Observation of Resonant Photon Blockade at Microwave Frequencies using Correlation Function Measurements
• Resonance fluorescence from a coherently driven semiconductor quantum dot in a cavity
• Atom-light crystallization of BECs in multimode cavities: Nonequilibrium classical and quantum phase transitions, emergent lattices, supersolidity, and frustration
• Dressed-state amplification by a superconducting qubit
• Ultra-Broadband Microwave Frequency-Comb Generation in Superconducting Resonators