arXiv subjects

Ilya Volkov

Publications and source records attributed to Ilya Volkov.

3 recordsLinked to original sources

arXiv2024

Nonradiant multiphoton states in quantum ring oligomers

Arrays of coupled dipole emitters support collective single- and multiphoton states that can preserve quantum excitations. One of the crucial characteristics of these states is the lifetime, which is fundamentally limited due to spontaneous emission. Here, we present a mechanism of the external coupling of two states via the radiation continuum, which allows for an increase in the lifetime of both single and double excitations. As an illustrative example, we consider a ringlike ensemble of quantum emitters, demonstrating that upon slight optimization of the structure geometry, one can increase the lifetime of singly and doubly excited states with nonzero orbital momentum by several orders of magnitude. The proposed mechanism of multiphoton excitation lifetime control has a universal nature and might be applied to a wide class of open quantum systems and quantum ensembles besides the particular geometry considered in this paper.

quant-ph↗

arXiv2023

Non-radiative configurations of a few quantum emitters ensembles: evolutionary optimization approach

In this work, we employ differential evolution algorithm to identify the optimal configurations of small atomic ensembles supporting quantum states with maximal radiative lifetime. We demonstrate that atoms mostly tend to assemble in quasi-regular structures with specific geometry strongly depending on the minimal interatomic distance $r_{min}$. We identified the clear underlying physics that governs the suppression of the radiative losses in particular geometries. However, we reveal that the specific configurations in small ensembles are not easily predictable based on the knowledge established for the arrays of large size. In particular, the states that inherit their properties from bound states in continuum in infinite lattices turn out to be the most subradiant in a wide range of $r_{min}$ values. We also show that for small interatomic distance the chains with modulated interatomic distances exhibit fast exponential decrease of the radiative losses with the size of the ensemble.

quant-ph↗

arXiv2023

Strongly subradiant states in planar atomic arrays

The optically trapped ensembles of atoms provide a versatile platform for storing and coherent manipulation of quantum information. However, efficient realization of quantum information processing requires long-lived quantum states protected from the decoherence e.g. via spontaneous emission. Here, we theoretically study collective dipolar oscillations in finite planar arrays of quantum emitters in free space and analyze mechanisms that govern the emergence of strongly subradiant collective states. We demonstrate that the external coupling between the collective states associated with the symmetry of the array and with the quasi-flat dispersion of the corresponding infinite lattice plays a crucial role in the boost of their radiative lifetime. We show that among different regular arrangements of the atoms the square atomic arrays support eigenstates with minimal radiative losses that scale with the total number of atoms $N_{tot}$ as $\propto N_{tot}^{-5}$.

quant-ph↗