False vacuum decay via bubble formation in ferromagnetic superfluids

Year: 2024

Authors: Zenesini A., Berti A., Cominotti R., Rogora C., Moss IG., Billam TP., Carusotto I., Lamporesi G., Recati A., Ferrari G.

Autors Affiliation: Univ Trento, CNR, Pitaevskii BEC Ctr, INO, Trento, Italy; Univ Trento, Dipartimento Fis, Trento, Italy; INFN, Trento Inst Fundamental Phys & Applicat, Trento, Italy; Newcastle Univ, Sch Math Stat & Phys, Newcastle Upon Tyne, England; Newcastle Univ, Joint Quantum Ctr JQC Durham Newcastle, Sch Math Stat & Phys, Newcastle Upon Tyne, England.

Abstract: Metastability stems from the finite lifetime of a state when a lower-energy configuration is available but only by tunnelling through an energy barrier. It is observed in many natural situations, including in chemical processes and in electron field ionization. In classical many-body systems, metastability naturally emerges in the presence of a first-order phase transition. A prototypical example is a supercooled vapour. The extension to quantum field theory and quantum many-body systems has attracted significant interest in the context of statistical physics, protein folding and cosmology, for which thermal and quantum fluctuations are expected to trigger the transition from the metastable state (false vacuum) to the ground state (true vacuum) through the probabilistic nucleation of spatially localized bubbles. However, the long-standing theoretical progress in estimating the relaxation rate of the metastable field through bubble nucleation has not been validated experimentally. Here we experimentally observe bubble nucleation in isolated and coherently coupled atomic superfluids, and we support our observations with numerical simulations. The agreement between our observations and an analytic formula based on instanton theory confirms our physical understanding of the decay process and promotes coherently coupled atomic superfluids as an ideal platform to investigate out-of-equilibrium quantum field phenomena. The transition from a metastable state to the ground state in classical many-body systems is mediated by bubble nucleation. This transition has now been experimentally observed in a quantum setting using coupled atomic superfluids.

Journal/Review: NATURE PHYSICS

Volume: 20 (4)      Pages from:   to:

More Information: We thank A. Biella, P. Hauke and Y. Castin for fruitful discussions. We acknowledge funding from Provincia Autonoma di Trento, from the National Institute for Nuclear Physics (INFN) through the FISH project, from the Italian Ministry of Education, University and Research under the PRIN2017 project CEnTraL (Protocol Number 20172H2SC4), from the European Union’s Horizon 2020 research and innovation programme through the STAQS and DYNAMITE projects of QuantERA II (Grant Agreement No. 101017733), from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 804305), from the UK Quantum Technologies for Fundamental Physics programme (Grant No. ST/W006162/1) and from the PNRR MUR project PE0000023-NQSTI. This work was supported by Q@TN, the joint laboratory between the University of Trento, Fondazione Bruno Kessler, INFN and the National Research Council.
KeyWords: Ground state; Quantum theory; Statistical Physics; Bubble nucleation; Chemical process; Electron field; Ferromagnetics; Field ionization; First-order phase transitions; Low energy configurations; Many-body systems; Metastabilities; Quantum field theory; Nucleation
DOI: 10.1038/s41567-023-02345-4

Citations: 3
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