Subradiance and Superradiant Long Range Excitation Transport among Quantum Emitter Ensembles in a Waveguide

TL;DR

This paper explores long-range collective excitation phenomena in quantum emitter ensembles coupled to waveguides, demonstrating the creation of subradiant states and efficient energy transfer, with potential applications in quantum technologies.

Contribution

It introduces a novel setup leveraging waveguide-mediated long-range interactions to generate subradiant states and control excitation transfer in quantum emitter ensembles.

Findings

Up to 50% excitation in subradiant states achieved.

Nearly lossless, fast energy transfer between ensembles demonstrated.

Control of transfer via ensemble positioning and randomness.

Abstract

In contrast to free space, in waveguides the dispersive and dissipative dipole-dipole interactions among quantum emitters exhibit a periodic behavior over remarkably long distances. We propose a novel setup exploiting this long-range periodicity in order to create highly excited subradiant states and facilitate fast controlled collective energy transport amongst far-apart ensembles coupled to a waveguide. For sufficiently large ensembles collective superradiant emission into the fiber modes dominates over its free space counterpart. We show that for a large number of emitters a fast transverse coherent pulse can create almost perfect subradiant states with up to $50\%$ excitation. On the other hand, for a coherent excitation of one sub-ensemble above an overall excitation fraction of $50\%$ we find a nearly lossless and fast energy transfer to the ground state sub-ensemble. This transport can be enhanced or suppressed by controlling the positions of the ensembles relative to each other, while it can also be realized with a random position distribution. In the optimally enhanced case this fast transfer appears as superradiant emission with subsequent superabsorption, yet, without a superradiant decay after the absorption. The highly excited subradiant states as well as the superradiant excitation transfer appear as suitable building blocks in applications like active atomic clocks, quantum batteries, quantum information protocols and quantum metrology procedures such as fiber-based Ramsey schemes.