English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The order parameter of a quantum-coherent many-body system can include aphase degree of freedom, which, in the presence of an electromagnetic field,depends on the choice of gauge. Because of the relationship between the phasegradient and the velocity, time-of-flight measurements reveal this gradient.Here, we make such measurements using initially trapped Bose-Einsteincondensates (BECs) subject to an artificial magnetic field. Vortices arenucleated in the BEC for artificial field strengths above a critical value,which represents a structural phase transition. By comparing tosuperfluid-hydrodynamic and Gross-Pitaevskii calculations, we confirmed thatthe transition from the vortex-free state gives rise to a shear in the releasedBEC's spatial distribution, representing a macroscopic method to measure thistransition, distinct from direct measurements of vortex entry. Shear is alsoaffected by an artificial electric field accompanying the artificial magneticfield turn-off, which depends on the details of the physical mechanism creatingthe artificial fields, and implies a natural choice of gauge. Measurements ofthis kind offer opportunities for studying phase in less-well-understoodquantum gas systems.

Gauge matters: Observing the vortex-nucleation transition in a Bose condensate