$P-V$ Criticality In the Extended Phase Space of Charged Accelerating   AdS Black Holes
  In this paper, we investigate the $P-V$ criticality and phase transition of charged accelerating AdS black holes in the extended thermodynamic phase space in analogy between black hole system and Van der Waals liquid-gas system, where the cosmological constant $\Lambda$ is treated as a thermodynamical variable interpreted as dynamic pressure and its conjugate quantity is the thermodynamic volume of the black holes. When the electric charge vanishes, we find that no $P-V$ criticality will appear but the Hawking-Page like phase transition will be present, just as what Schwarzschild-AdS black holes behave like. For the charged case, the $P-V$ criticality appears and the accelerating black holes will undergo a small black hole/large phase transition under the condition that the acceleration parameter $A$ and the horizon radius $r_h$ meet a certain simple relation $A r_h=a$, where $a$ is a constant in our discussion. To make $P-V$ criticality appear, there exists an upper bounds for constant $a$. When $P-V$ criticality appears, we calculate the critical pressure $P_{c}$, critical temperature $T_{c}$ and critical specific volume $r_{c}$, and we find that $\frac{P_{c}r_{c}}{T_{c}}$ is an universal number. 
Hang Liu and Xin-he Meng
gr-qc hep-th