Correlated emission of electron-current waves

TL;DR

This paper explores the conditions for correlated electron emission from color centers, revealing how emitter spacing influences superradiance and subradiance, with potential implications for quantum sensing and memory.

Contribution

It introduces a detailed analysis of electron-mediated correlated emission, highlighting the role of Fermi wavelength and velocity in emission phenomena, which was not previously characterized.

Findings

Subradiance occurs when emitters are closer than the Fermi wavelength.

Superradiance requires spacing less than sqrt(λ_F v_F/Δ).

Emitted current bursts form spiral patterns.

Abstract

Correlated emission of light offer a potential avenue for entanglement generation between atomic spins, with potential application for sensing and quantum memory. In this work, we investigate the conditions for the correlated emission by color centers into an electronic bath of conduction electrons. Unlike emission into bosonic modes, electrons can absorb energy via two-particle processes across a large range of length scales. We find that two length scales are particularly relevant: one set by the Fermi velocity and the frequency of the color centers $v_F/\Delta$, and the other set by the Fermi wavelength $\lambda_F \ll v_F/\Delta$. Subradiance requires emitters to be spaced at a distance closer than the Fermi wavelength, while superradiance requires spacing less than $\sqrt{\lambda_F v_F/\Delta}$, so long as the emitters are initialized with coherence. We show that the emitted current burst has a spiral form, and we discuss the experimental possibility to observe correlated dissipation by color-center qubits coupled to electronic environments.