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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Spontaneous symmetry breaking plays a key role in our understanding ofnature. In a relativistic field theory, a broken continuous symmetry leads tothe emergence of two types of fundamental excitations: massless Nambu-Goldstonemodes and a massive `Higgs' amplitude mode. An excitation of Higgs type is ofcrucial importance in the standard model of elementary particles and alsoappears as a fundamental collective mode in quantum many-body systems. Whethersuch a mode exists in low-dimensional systems as a resonance-like feature orbecomes over-damped through coupling to Nambu-Goldstone modes has been asubject of theoretical debate. Here we reveal and study a Higgs mode in atwo-dimensional neutral superfluid close to the transition to a Mott insulatingphase. We unambiguously identify the mode by observing the expected softeningof the onset of spectral response when approaching the quantum critical point.In this regime, our system is described by an effective relativistic fieldtheory with a two-component quantum-field, constituting a minimal model forspontaneous breaking of a continuous symmetry. Additionally, all microscopicparameters of our system are known from first principles and the resolution ofour measurement allows us to detect excited states of the many-body system atthe level of individual quasiparticles. This allows for an in-depth study ofHiggs excitations, which also addresses the consequences of reduceddimensionality and confinement of the system. Our work constitutes a first stepin exploring emergent relativistic models with ultracold atomic gases.

The `Higgs' Amplitude Mode at the Two-Dimensional Superfluid-Mott Insulator Transition