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

Motivated by recent experiments on atomic Dirac fermions in a tunablehoneycomb optical lattice, we study the attractive Hubbard model ofsuperfluidity in the anisotropic honeycomb lattice. At weak-coupling, we findthat the maximum mean field pairing transition temperature, as a function ofdensity and interaction strength, occurs for the case with isotropic hoppingamplitudes. In this isotropic case, we go beyond mean field theory and studycollective fluctuations, treating both pairing and density fluctuations forinteraction strengths ranging from weak to strong coupling. We find evidencefor a sharp sound mode, together with a well-defined Leggett mode over a wideregion of the phase diagram. We also calculate the superfluid order parameterand collective modes in the presence of nonzero superfluid flow. Theflow-induced softening of these collective modes leads to dynamicalinstabilities involving stripe-like density modulations as well as aLeggett-mode instability associated with the natural sublattice symmetrybreaking charge-ordered state on the honeycomb lattice. The latter provides anon-trivial test for the experimental realization of the one-band Hubbardmodel. We delineate regimes of the phase diagram where the critical current islimited by depairing or by such collective instabilities, and discussexperimental implications of our results.

Superfluidity of Dirac Fermions in a Tunable Honeycomb Lattice: Cooper Pairing, Collective Modes, and Critical Currents