Soliton solutions of an improved quark mass density-dependent model at finite temperature

The improved quark mass density-dependent model (IQMDD) based on soliton bag model is studied at finite temperature. Applying the finite temperature field theory, the effective potential of the IQMDD model and the bag constant $B(T)$ have been calculated at different temperatures. It is shown that there is a critical temperature ${T}_{C}\ensuremath{\simeq}110\phantom{\rule{0.3em}{0ex}}\mathrm{MeV}$. We also calculate the soliton solutions of the IQMDD model at finite temperature. It turns out that when $Tl{T}_{C}$, there is a bag constant $B(T)$ and the soliton solutions are stable. However, when $Tg{T}_{C}$ the bag constant $B(T)=0$ and there is no soliton solution, therefore, the confinement of quarks are removed quickly.