  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.
