Electric conductivity in finite-density SU(2) lattice gauge theory with dynamical fermions
| Autor: | L. von Smekal, Pavel Buividovich, Dominik Smith |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Physical Review D. 102 |
| ISSN: | 2470-0029 2470-0010 |
| DOI: | 10.1103/physrevd.102.094510 |
| Popis: | We study the dependence of the electric conductivity on chemical potential in finite-density $SU(2)$ gauge theory with ${N}_{f}=2$ flavors of rooted staggered sea quarks, in combination with Wilson-Dirac and domain-wall valence quarks. The pion mass is reasonably small with ${m}_{\ensuremath{\pi}}/{m}_{\ensuremath{\rho}}\ensuremath{\approx}0.4$. We concentrate in particular on the vicinity of the chiral crossover, where we find the low-frequency electric conductivity to be most sensitive to small changes in fermion density. Working in the low-density QCD-like regime with spontaneously broken chiral symmetry, we obtain an estimate of the first nontrivial coefficient $c(T)$ of the expansion of conductivity $\ensuremath{\sigma}(T,\ensuremath{\mu})=\ensuremath{\sigma}(T,0)(1+c(T){(\ensuremath{\mu}/T)}^{2}+O({\ensuremath{\mu}}^{4}))$ in powers of $\ensuremath{\mu}$, which has rather weak temperature dependence and takes its maximal value $c(T)\ensuremath{\approx}0.10\ifmmode\pm\else\textpm\fi{}0.07$ around the critical temperature. At larger densities and lower temperatures, the conductivity quickly grows toward the diquark condensation phase and also becomes closer to the free-quark result. As a by-product of our study we confirm the conclusions of previous studies with heavier pion that for $SU(2)$ gauge theory the ratio of crossover temperature to pion mass ${T}_{c}/{m}_{\ensuremath{\pi}}\ensuremath{\approx}0.4$ at $\ensuremath{\mu}=0$ is significantly smaller than in real QCD. |
| Databáze: | OpenAIRE |
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