BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:D.V. Kupriyanov DTSTART:20240908T130000Z DTEND:20240908T134000Z DTSTAMP:20260423T022738Z UID:QOART/39 DESCRIPTION:Title: R adiative Coupling of a Multilevel Atom with a Dielectric Structure\nby D.V. Kupriyanov as part of Quantum Optics and Related Topics\n\n\nAbstrac t\nThe coupling of quantum emitters\, such as cold atoms\, with nanoscale structures like dielectric waveguides and subwavelength resonators brings new opportunities for quantum technology. The directional emission of indi vidual photons could create certain conditions for a quantum computer inte rface based on neutral atoms. Prototypes of similar nanophotonic devices h ave been already demonstrated in experiments involving the confinement of atoms within microresonators\, photonic crystal structures\, and nanofiber s [1]. We propose a microscopic scheme for calculating radiation correctio ns to the energy spectrum of a single-electron atom in the presence of a n anoscale dielectric object. The calculation takes into account the complet e Zeeman structure of an isolated atomic transition and can be applied to systems with arbitrary geometric configurations. At the studied frequencie s\, the dielectric properties can be replicated by replacing the bulk mate rial with an ensemble of two-level atoms with resonant transition frequenc ies being offset from the radiation frequency of a reference atom [2]. We demonstrate the approach by applying it to various nanostructure geometrie s used in the experiments [3] and conduct a comparative analysis to demons trate the advantages of exciting an atom at frequencies close to the edge of the Brillouin zone in asymmetric photonic crystals. Figure 1 demonstrat es spectral parameters of the caesium-133 atom placed near the one-dimensi onal asymmetric photonic crystal. Quasi-energy sublevels exhibit twofold d egeneracy and non-orthogonality between states from different energy level s\, which we show is connected to the nontrivial axial symmetry in atomic excitation and decay channels. The observed increase in atomic decay rate is accompanied by its directional radiation into a waveguide mode\, which is significant for developing quantum interfaces based on individual atoms and photons. Due\nto this radiation\, a resonant scattering channel can b e used to create a chain of entangled atoms. The phase of the atomic state changes by 180 degrees during the resonant scattering of photons\, that i s a critical aspect of the C-Z entanglement protocol\, a promising scheme proposed as an alternative to the Rydberg blockade protocol.\n\nAcknowledg ements: The work was funded by the Russian Science Foundation (Project No. 23-72-10012).\n\nReferences\n\n[1] D E Chang\, J S Douglas\, A González- Tudela\, C-L Hung and H J Kimble\, Rev. Mod. Phys. 90\, 031002 (2018)\n\n[ 2] N A Moroz\, L V Gerasimov\, A D Manukhova and D V Kupriyanov\, Phys. Re v. A 109\, 013714 (2024)\n\n[3] N Fayard\, A Bouscal\, J Berroir\, A Urvoy \, T Ray\, S Mahapatra\, M Kemiche\, J A Levenson\, J-J\nGreffet\, K Bench eikh\, J Laurat and C Sauvan\, Opt. Express 30\, 45093 (2022)\n LOCATION:https://researchseminars.org/talk/QOART/39/ END:VEVENT END:VCALENDAR