Details

Autor(en) / Beteiligte

• Kim, Keun-Young
• Kim, Kyung Kiu
• Park, Miok

Titel

A simple holographic superconductor with momentum relaxation

Ist Teil von

• The journal of high energy physics, 2015-04, Vol.2015 (4), p.1, Article 152

Ort / Verlag

Berlin/Heidelberg: Springer Berlin Heidelberg

Erscheinungsjahr

2015

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• A bstract We study a holographic superconductor model with momentum relaxation due to massless scalar fields linear to spatial coordinates( ψ I  =  βδ Ii x i ), where β is the strength of momentum relaxation. In addition to the original superconductor induced by the chemical potential( μ ) at β = 0, there exists a new type of superconductor induced by β even at μ = 0. It may imply a new ‘pairing’ mechanism of particles and antiparticles interacting with β , which may be interpreted as ‘impurity’. Two parameters μ and β compete in forming superconducting phase. As a result, the critical temperature behaves differently depending on β/μ . It decreases when β/μ is small and increases when β/μ is large, which is a novel feature compared to other models. After analysing ground states and phase diagrams for various β/μ , we study optical electric( σ ), thermoelectric( α ), and thermal( κ ¯ ) conductivities. When the system undergoes a phase transition from normal to a superconducting phase, 1 /ω pole appears in the imaginary part of the electric conductivity, implying infinite DC conductivity. If β/μ < 1, at small ω , a two-fluid model with an imaginary 1 /ω pole and the Drude peak works for σ , α , and κ ¯ , but If β/μ > 1 a non-Drude peak replaces the Drude peak. It is consistent with the coherent/incoherent metal transition in its metal phase. The Ferrell-Glover-Tinkham (FGT) sum rule is satisfied for all cases even when μ = 0.