Superradiance of Harmonic Oscillators

TL;DR

This paper explores superradiance phenomena in ensembles of harmonic oscillators, demonstrating conditions for superradiant and subradiant states, and proposing physical platforms and state preparation methods for observing these effects.

Contribution

It introduces the concept of harmonic oscillator superradiance, identifies conditions for superradiant and subradiant states, and generalizes protocols for preparing entangled states in circuit QED.

Findings

Superradiance can occur in harmonic oscillator ensembles under specific conditions.

Superradiant and subradiant states are multimode squeezed and entangled states.

The paper proposes experimental platforms and state preparation protocols for observing these effects.

Abstract

Superradiance, the enhanced collective emission of light from a coherent ensemble of quantum systems, has been typically studied in atomic ensembles. In this work we study the enhanced emission of energy from coherent ensembles of harmonic oscillators. We show that it should be possible to observe harmonic oscillator superradiance in a variety of physical platforms such as waveguide arrays in integrated photonics and resonator arrays in circuit QED. We find general conditions specifying when emission is superradiant and subradiant and find that superradiant, subradiant and dark states take the form of multimode squeezed coherent states and highly entangled multimode Fock states. The intensity, two-mode correlations and fraction of quanta trapped in the system after decay are calculated for a range of initial states including multimode Fock, squeezed, coherent and thermal states. In order to explore these effects, the Law and Eberly protocol [C. K. Law and J. H. Eberly, Phys. Rev. Lett. 76, 1055 (1996)] is generalized to prepare highly entangled multimode Fock states in circuit QED.