Coherent inflationary dynamics for Bose–Einstein condensates crossing a quantum critical point

Quantum phase transitions, transitions between many-body ground states, are of extensive interest in research ranging from condensed-matter physics to cosmology 1 – 4 . Key features of the phase transitions include a stage with rapidly growing new order, called inflation in cosmology 5 , followed by...

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Bibliographic Details
Published in:Nature physics 2018-03, Vol.14 (3), p.269-272
Main Authors: Feng, Lei, Clark, Logan W., Gaj, Anita, Chin, Cheng
Format: Article
Language:English
Subjects:
639/766/119/2791
639/766/119/2795
639/766/36/1125
Atomic
Bose-Einstein condensates
Classical and Continuum Physics
Coherence
Complex Systems
Condensates
Condensed Matter Physics
Critical point
Defects
Dynamics
Inflation (cosmology)
Letter
Mathematical and Computational Physics
Molecular
Optical and Plasma Physics
Phase transitions
Physics
Physics and Astronomy
Theoretical
Variation
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Summary:Quantum phase transitions, transitions between many-body ground states, are of extensive interest in research ranging from condensed-matter physics to cosmology 1 – 4 . Key features of the phase transitions include a stage with rapidly growing new order, called inflation in cosmology 5 , followed by the formation of topological defects 6 – 8 . How inflation is initiated and evolves into topological defects remains a hot topic of debate. Ultracold atomic gas offers a pristine and tunable platform to investigate quantum critical dynamics 9 – 21 . We report the observation of coherent inflationary dynamics across a quantum critical point in driven Bose–Einstein condensates. The inflation manifests in the exponential growth of density waves and populations in well-resolved momentum states. After the inflation stage, extended coherent dynamics is evident in both real and momentum space. We present an intuitive description of the quantum critical dynamics in our system and demonstrate the essential role of phase fluctuations in the formation of topological defects. An ultracold quantum gas experiment shows that, when it crosses the many-body phase transition, the original ground state can evolve coherently into the new emergent phase, reflecting the initial global coherence presented in the system.
ISSN:1745-2473
1745-2481
DOI:10.1038/s41567-017-0011-x