Non-classical photon statistics in frequency-modulated double quantum dot cavity systems

This study investigates the quantum dynamics of a double quantum dot (DQD) system integrated with a leaking microwave resonator. The researchers aim to determine if periodic modulation of the DQD energy levels—a technique known as Floquet engineering—can be used to control the statistical properties of the emitted microwave photons. By applying a continuous driving field to the DQD, the authors create resonance conditions between the qubit and the cavity. They derive a master equation for the system, accounting for electronic, phononic, and photonic reservoirs, to calculate the steady-state photon statistics, including the Fano factor and higher-order correlation functions.

The theoretical analysis demonstrates that under specific driving conditions and low environmental temperatures, the cavity emits a flux of single photons that exhibit sub-Poissonian statistics. This is confirmed by a Fano factor less than unity and a hierarchy of correlation functions where the second-order correlation is smaller than the third-order correlation. The study shows that the DQD-cavity system acts as a tunable nonlinear platform capable of producing non-classical light, even in the absence of a direct DC current, provided the coupling strengths and environmental dissipation are carefully managed.

This research provides a theoretical framework for designing on-chip microwave quantum devices. By using DQD systems as an electronic interface, researchers can manipulate photon statistics to create non-classical light sources. These findings are particularly relevant for quantum information processing and the development of scalable solid-state cavity quantum electrodynamics (QED) platforms, where deterministic control over photon emission is essential for mediating quantum correlations.