Mainz 2026 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 49: Quantum Communication, Networks, Repeaters, & QKD I

Q 49.2: Vortrag

Donnerstag, 5. März 2026, 11:15–11:30, P 10

Towards a spin-exchange collision-based optical quantum memory in noble-gas spins — •Alexander Erl^1,2, Norman Vincenz Ewald^1,2, Andrés Medina Herrera², Denis Uhland³, Wolfgang Kilian², Jens Voigt², Ilja Gerhardt³, and Janik Wolters^1,4 — ¹DLR, Institute of Space Research, Berlin — ²PTB, 8.2 Biosignals, Berlin — ³LUH, Institute of Solid State Physics, Hannover — ⁴TUB, Institute of Physics and Astronomy, Berlin

A critical limitation on current room-temperature quantum memory systems [1] is the maximum achievable storage time on the order of a few µs, which must be extended for various quantum communication applications. We report on our first steps towards a long-lived quantum memory with an all-optical interface based on a mixture of ¹²⁹Xe noble gas and ¹³³Cs alkali metal vapor, both confined in a glass cell at near room temperature. The interface relies on EIT, implemented through a Λ-scheme in the Zeeman sublevels of the long-lived hyperfine ground states of ¹³³Cs, coupled to an excited state via the D₁ line at 895 nm [2]. A sufficiently long-lived Cs spin coherence is essential for entering the strong spin-exchange coupling regime, where collisions can efficiently transfer the stored quantum excitation from the alkali vapor to the noble-gas ensemble [3]. The coherence time of ¹²⁹Xe, which can extend up to several hours [4], offers the potential for long-term storage of quantum information in collective atomic excitations. [1] M. Jutisz et al., Phys. Rev. Applied 23, 024045 (2025); [2] G. Buser et al., PRX, 020349 (2022); [3] O. Katz et al., PRA 105, 042606 (2022); [4] C. Gemmel et al., EPJ D 57, 303-320 (2010)

Keywords: Quantum memory; Quantum repeater; Quantum communication