RQC Seminar

222nd RQC Seminar

• Speaker

  Dr. Alexander Poddubny
  ( Weizmann Institute of Science, Israel )

• Date

  16:00-17:00 (4:00 p.m. - 5:00 p.m.), November 10, 2025 Monday)

• Venue

  Hybrid(ZOOM・ Wako Main Research Bldg. 3F 345-347 Seminar Room / 研究本館3階 セミナー室 (345-347) (C01))

• Title

  Subradiant States and Subradiant Correlations

• Inquiries

  norilab_rqc_assist[at]ml.riken.jp

Abstract
The study of collective photon interactions with arrays of atoms is by now a mature field, going back at least as far as Dicke’s discovery of superradiance in 1954. The main idea is that a photon mode can couple to multiple distant atoms at the same time, and these multiple couplings can interfere either constructively (leading to enhanced and faster emission, superradiance) or destructively (leading to slower and weaker emission, subradiance). The last decade has seen a vivid renaissance of interest in collective atom-photon interactions. First, one can now coherently control positions and couplings of multiple natural or artificial atoms in a lab with unprecedented precision at the level of individual atoms. Second, it is now clear that there is a lot to explore in collective interactions beyond the Dicke model.

The abundance of unexplored physics becomes especially evident for subradiant states. The full Hilbert space size for an array of N two-level atoms scales as 2N, while the Dicke-type models have probed only a reduced N+1-dimensional space of symmetric states. To paraphrase the beginning of Tolstoy’s “Anna Karenina,” all superradiant states are similar to each other, but all subradiant states are different. We focus on the question “what is the darkest state?”, that is apparently much harder than the question “what is the brightest state?”.

In this talk, I will start with a review of recent theoretical and experimental progress in the study of subradiant states, including our results on waveguide coupled atom arrays [1-5]. I will also discuss the conditions for the presence or absence of long-living subradiant correlations in the driven-dissipative setups, where atoms interact with light.

References

[1] A.S. Sheremet, M.I. Petrov, I.V. Iorsh, A.V. Poshakinskiy, A.N. Poddubny, Rev. Mod. Phys. 95, 015002 (2023)
[2] A.V. Poshakinskiy and A.N. Poddubny, Phys. Rev. Lett. 127, 173601 (2021)
[3] A.N. Poddubny, Phys. Rev. A 106, L031702 (2022)
[4] J. Shi and A.N. Poddubny, Phys. Rev. A 110, 053707 (2024)
[5] N. Leppenen and A.N. Poddubny, arXiv:2507.19467