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arXiv · 1711.01869

Observation of deconfinement in a cold dense quark medium

V. G. Bornyakov·V. V. Braguta·E. -M. Ilgenfritz·A. Yu. Kotov·A. V. Molochkov·A. A. Nikolaev
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Abstract

In this paper we study the confinement/deconfinement transition in lattice $SU(2)$ QCD at finite quark density and zero temperature. The simulations are performed on an $32^4$ lattice with rooted staggered fermions at a lattice spacing $a = 0.044 \mathrm{~fm}$. This small lattice spacing allowed us to reach very large baryon density (up to quark chemical potential $\mu_q > 2000 \mathrm{~MeV}$) avoiding strong lattice artifacts. In the region $\mu_q\sim 1000 \mathrm{~MeV}$ we observe for the first time the confinement/deconfinement transition which manifests itself in rising of the Polyakov loop and vanishing of the string tension $\sigma$. After the deconfinement is achieved at $\mu_q > 1000 \mathrm{~MeV}$, we observe a monotonous decrease of the spatial string tension $\sigma_s$ which ends up with $\sigma_s$ vanishing at $\mu_q > 2000 \mathrm{~MeV}$. From this observation we draw the conclusion that the confinement/deconfinement transition at finite density and zero temperature is quite different from that at finite temperature and zero density. Our results indicate that in very dense matter the quark-gluon plasma is in essence a weakly interacting gas of quarks and gluons without a magnetic screening mass in the system, sharply different from a quark-gluon plasma at large temperature.

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V. G. Bornyakov, V. V. Braguta, E. -M. Ilgenfritz, A. Yu. Kotov, A. V. Molochkov, A. A. Nikolaev. 2017-11-06. Observation of deconfinement in a cold dense quark medium. https://doi.org/10.1007/jhep03(2018)161

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