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

We apply a spin-coherent states formalism to study the central-spin modelwith monochromatic bath and symmetric coupling (the Mermin model); inparticular, we derive analytic expressions for the density of states in thethermodynamic limit when the number of bath spins is taken to infinity. Fromthe thermodynamic limit spectra we show the phase diagram for the system can bedivided into four regions, partitioned on the one hand into a symmetric(non-degenerate) phase or a broken symmetry (degenerate) phase, and on theother hand by the case of overlapping or non-overlapping energy surfaces. Thenature and position of singularities appearing in the energy surfaces change asone moves from region to region. Our spin-coherent states formalism naturallyleads us to the Majorana representation, which is useful to transform theSchr\"odinger equation into a Ricatti-like form that can be solved in thethermodynamic limit to obtain closed-form expressions for the density ofstates. The energy surface singularities correspond with critical points in thedensity of states. We then use our results to compute expectation values forthe system that help to characterize the nature of the quantum phase transitionbetween the symmetric and broken phases.

Density of states and quantum phase transition in the thermodynamic limit of the Mermin central-spin model