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

Near a quantum-critical point in a metal a strong fermion-fermioninteraction, mediated by a soft boson, destroys fermionic coherence and alsogives rise to superconductivity. In a class of large $N$ models, one wouldnaively expect an incoherent (non-Fermi liquid) normal state behavior topersist down to $T=0$. However, this is not the case for quantum-criticalsystems described by Eliashberg theory, where non-Fermi liquid part of theself-energy $\Sigma (\omega_m)$ is large for a generic Matsubara frequency$\omega_m = \pi T(2m+1)$, but vanishes at $\omega_m = \pm \pi T$, while thepairing interaction between fermions with these two frequencies remains strong.This peculiarity gives rise to a non-zero $T_c$ even at large $N$[Y. Wang et alPRL 117, 157001 (2016)]. We consider the system behavior below $T_c$ andcontrast the two cases when $\omega_m = \pm \pi T$ are either special or not.We obtain the solution of the non-linear gap equations in real frequency axisand obtain the spectral function $A(\omega)$ and the density of states$N(\omega)$. In a conventional BCS-type superconductor $A(\omega)$ and$N(\omega)$ are peaked at the gap value $\Delta (T)$, and the peak positionshifts to a smaller $\omega$ as temperature increases, i.e. the gap "closesin". However when superconductivity is induced by fermions with $\omega_m = \pm\pi T$, the peak in $N(\omega)$ remains at a finite frequency even at $T=T_c-0$, the gap just "fills in". The spectral function $A(\omega)$ eithershows almost the same "gap filling" behavior, or its peak position shifts tozero frequency already at a finite $\Delta$ ("emergent Fermi arc" behavior),depending on the strength of the thermal contribution. We compare our resultswith the data for the cuprates and argue that "gap filling" behavior holds inthe antinodal region, while the "emergent Fermi arc" behavior holds in thenodal region.

physical review. b./physical review. b

The special role of the first Matsubara frequency for superconductivity  near a quantum-critical point -- the non-linear gap equation below $T_c$ and  spectral properties in real frequencies