Subregion complexity and confinement–deconfinement transition in a holographic QCD model

We study the subregion complexity in a semi-analytical holographic QCD model. Two cases with different warped factor are considered and both can realize confinement–deconfinement transition. By studying the behavior of the renormalized holographic complexity density Cˆ versus the subregion length scale ℓ, we find that for both cases, Cˆ always experiences a discontinuity at certain critical value ℓc in confinement phases, while it is always continuous in deconfinement phases. This property may be seen as a signal to characterize confinement or deconfinement phases. The behavior of Cˆ versus the temperature and chemical potential is also investigated and our results show that Cˆ exhibits behavior characterizing the type of the transition. That is, it experiences a discontinuity at the transition temperature for μμc where the transition turns into a turnover. These results imply that the renormalized holographic complexity density may be used as a good parameter to characterize the corresponding phase structures