Spectral signatures of many-body localization with interacting photons

Understand

Statistical mechanics is founded on the assumption that a system can reach thermal equilibrium, regardless of the starting state.

• Interactions between particles facilitate thermalization, but, can interacting systems always equilibrate regardless of parameter values\,? The energy spectrum of a system can answer this question and reveal the nature of the underlying phases.
• However, most experimental techniques only indirectly probe the many-body energy spectrum.
• Using a chain of nine superconducting qubits, we implement a novel technique for directly resolving the energy levels of interacting photons.