Phase fluctuations determine the low-energy properties of quantum condensates. However, at the condensation threshold, both density and phase fluctuations are relevant. While strong emphasis has been given to the investigation of phase fluctuations, which dominate the physics of the quantum system away from the critical point, number fluctuations have been much less explored even in thermal equilibrium. In this work, we report experimental observation and theoretical description of fluctuations in a circularly confined nonequilibrium Bose-Einstein condensate of polaritons near the condensation threshold. We observe critical fluctuations, which combine the number fluctuations of a single-mode condensate state and competition between different states. The latter is analogous to mode hopping in photon lasers. Our theoretical analysis indicates that this phenomenon is of a quantum character, while classical noise of the pump is not sufficient to explain the experiments. The manifestation of a critical quantum state competition unlocks possibilities for the study of condensate formation while linking to practical realizations in photonic lasers.
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Searching the QCD critical endpoint with lattice simulations
We discuss the usefulness of various lattice observables especially fluctuations to locate the QCD critical endpoint. We apply different models to interpret our results for the baryon fluctuations up to µ 8 from simulations at imaginary chemical potentials.
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- Award ID(s):
- 1654219
- NSF-PAR ID:
- 10248473
- Editor(s):
- Vitev, I.; da Silva, C.; Mioduszewski, S.; Ratti, C.; Sarcevic, I.; Schlegel, M.
- Date Published:
- Journal Name:
- EPJ Web of Conferences
- Volume:
- 235
- ISSN:
- 2100-014X
- Page Range / eLocation ID:
- 02004
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1051/epjconf/202023502004
