Coherent control of an all-atomic waveguide: trap and release of an excitation

H. L. Haroutyunyan, Gerard Nienhuis

R. Gutiérrez-Jáuregui, Ana Asenjo-Garcı́a

We introduce a protocol for dynamical dispersion engineering in an atomic chain formed by an ordered array of multilevel atoms with subwavelength lattice constant. This chain supports dark states that are protected from dissipation and can be understood as spin waves traveling along the array. By using an external control field with a spatially varying elliptical polarization we correlate internal and external degrees of freedom of the array in a controllable way. The coherent control over atomic states translates into control over the group velocity of the spin waves. A traveling excitation can be stored and released without dissipation by adiabatically changing the control field amplitude. This protocol is an alternative to the more conventional electromagnetically induced transparency and exemplifies the rich physics born of the interplay between coherent control and correlated decay.

Yu. V. Rozhdestvenskiǐ

Wei Chen, Kuan-Ting Lin, Guin-Dar Lin +1 more

Driven-dissipative quantum emitters provide a powerful platform for controllable excitation storage and release, with promising applications in quantum batteries and quantum storage. Yet, transient excitation transfer in collective many-body systems is often obscured by the intricate interplay among coherent driving, dissipation, and correlation dynamics. Here, we uncover a scalable excitation-storage mechanism in two emitter ensembles coupled to a semi-infinite waveguide. A coherently driven ensemble acts as an effective excitation reservoir, while a second ensemble positioned near a dissipative node serves as a subradiant storage medium. Surprisingly, when the driven ensemble largely exceeds the storage ensemble in size, the transfer dynamics enters a nearly correlation-free regime, allowing the driven ensemble to behave effectively as a classical excitation source. This reveals a simple scaling law for optimal excitation transfer, under which the storage ensemble approaches near-complete population inversion as the driven ensemble size increases. Building on this mechanism, we propose a three-stage storage-and-release protocol enabling fast excitation storage and controllable photon emission. Our results demonstrate how coherent and dissipative collective interactions can be jointly harnessed for quantum energy storage and programmable nonequilibrium dynamics in waveguide QED platforms.

Vladimir S. Melezhik

We have developed a method for treating ultracold pair collisions in confined geometry of tight atomic waveguides. With this approach we have predicted and analyzed a few novel resonant and multichannel effects induced by confining traps in ultracold atomic collisions. In this report we discuss our model yielding the shifts and widths of magnetic Feshbach resonances in tight atomic waveguides. We also briefly discuss a resonant mechanism of molecule formation in atomic traps with transferring the energy release to the center-of-mass excitation while forming molecule and dipolar confinement-induced resonances in waveguides. These results could potentially be used experimentally.

Warren S. Warren