Correlations between the deconfining and chiral transitions in holographic QCD

We consider an improved soft-wall AdS/QCD model coupled to an Einstein-dilaton system, which offers a way to study the deconfining and chiral transitions simultaneously. The correlation between these two transitions has been investigated in detail in the Einstein-dilaton-scalar system with the bulk scalar field representing the vacuum of matters in the flavor sector of the model. We find that the effects of the scaling dimension Delta of the dual operator of the dilaton manifest in chiral transitions, although the equations of state can all be matched with the two-flavor lattice results for Delta = 2.5, 3, 3.5 in the decoupling case of beta = 0. In the weak-coupling case with smaller beta, both the equation of state and the chiral transition exhibit a crossover behavior and turn into first-order phase transitions with the increase of beta.