Programmable Superradiance in an Interacting Qubit Array

TL;DR

This paper demonstrates a superconducting qubit array coupled to a microwave waveguide, enabling control and observation of collective superradiant and subradiant states, revealing complex many-body quantum dynamics.

Contribution

It introduces a tunable, site-resolved superconducting qubit platform to study collective emission beyond the ideal Dicke model, with direct microscopic measurements.

Findings

Controlled superradiance and subradiance in a qubit array.

Observation of many-body decay dynamics across excitation manifolds.

Enhanced stability of collective states against dephasing.

Abstract

When multiple quantum emitters couple to a common electromagnetic environment, interference in their collective radiative dynamics gives rise to superradiance and subradiance. In regimes where coherent interactions and collective dissipation compete, the microscopic many-body dynamics and quantum correlations among the emitters that underlie superradiance and subradiance are theoretically challenging and remain experimentally elusive, even though collective emission has been observed in many physical systems. Here, we realize a superconducting qubit array coupled to a common microwave waveguide that mediates collective dissipation, with simultaneous access to coherent interactions and microscopic measurements of many-body dynamics. Engineered qubit-waveguide couplings with tunable amplitude and phase enable control of collective interference and the resulting super- and subradiant states. Leveraging site-resolved control and readout, we directly observe the microscopic decay dynamics of multi-qubit states across different excitation manifolds and track the evolution of populations and tunable quantum correlations. We reveal collective decay in regimes beyond the ideal Dicke model, where strong qubit-qubit interactions stabilize superradiance and subradiance against local dephasing and reshape decay pathways through spatially and spectrally structured many-body eigenstates. Our results establish a flexible platform for exploring collective phenomena in many-body quantum optics and driven-dissipative approaches to robust quantum information processing.