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Paper IPM / P / 16845  


Abstract:  
In this paper, we study the von Neumann entropy of Hawking radiation S_{R} from a d+2dimensional Hyperscaling Violating (HV) black brane which is coupled to two Minkowski spacetimes as the thermal baths. We consider two different situations for the matter fields: First, the matter fields are described by a CFT_{d+2} whose central charge c is very large. Second, they are described by a d+2 dimensional HV QFT which has a holographic gravitational theory that is a HV geometry at zero temperature. For both cases, we calculate the Page curve of the Hawking radiation as well as the Page time t_{Page}. For the first case, S_{R} grows linearly with time before the Page time and saturates after this time. Moreover, t_{Page} is proportional to [(2 S_{th})/(c T)], where S_{th} and T are the thermal entropy and temperature of the black brane. For the second case, when the hyperscaling violation exponent θ_{m} of the matter fields is zero, the results are very similar to those for the first case. However, when θ_{m} ≠ 0, the entropy of Hawking radiation grows exponentially before t_{Page} and saturates after this time. Furthermore, the Page time is proportional to log( [1/(G_{N,r})] ) , where G_{N,r} is the renormalized Newton's constant. It was also observed that for both cases, t_{Page} is a decreasing and an increasing function of the dynamical exponent z and hyperscaling violation exponent θ of the black brane geometry, respectively. Moreover, for θ_{m} ≠ 0, it is a decreasing function of θ_{m}.
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