It is difficult for the metaphysician to not be fascinated by Stephen Hawking’s question, ‘What is it that breathes fire into the equations and makes a universe for them to govern?’ (Hawking, 1988, p. 174). Like a Tuscan countryside in the eyes of a painter, this statement inspires quite the stream of consciousness, at least in my idiosyncratic mind. For one thing, Hawking’s wording sounds as i...

OBJECTIVES To estimate the transmissibility of the Ice Bucket Challenge among globally influential celebrities and to identify associated risk factors. DESIGN Retrospective cohort study. SETTING Social media (YouTube, Facebook, Twitter, Instagram). PARTICIPANTS David Beckham, Cristiano Ronaldo, Benedict Cumberbatch, Stephen Hawking, Mark Zuckerberg, Oprah Winfrey, Homer Simpson, and Kermi...

Is the Hawking flux “thermal”? Unfortunately, the answer to this seemingly innocent question depends on a number of often unstated, but quite crucial, technical assumptions built into modern (mis-)interpretations of the word “thermal”. The original 1850’s notions of thermality — based on classical thermodynamic reasoning applied to idealized “black bodies” or “lamp black surfaces” — when supple...

Hawking radiation is an important and prominent quantum effect that arises upon the quantization of matter fields in a background spacetime with an event horizon. This is due to the different vacuum states between the vicinity of the event horizon and the asymptotic infinity [1]. Apart from the original derivation [1], there are other approaches [2, 3] each having their own merits and demerits....

A six-dimensional black string is considered and its Bekenstein-Hawking entropy computed. It is shown that to leading order above extremality, this entropy precisely counts the number of string states with the given energy and charges. This identification implies that Hawking decay of the near-extremal black string can be analyzed in string perturbation theory and is perturbatively unitary.

Renyi entropies of a black hole are evaluated by counting the states of the Hawking radiation which fills a thin shell surrounding the horizon. The width of the shell is determined from its energy content and the corresponding mass defect. The Bekenstein-Hawking formula for the entropy of the black hole is correctly reproduced.

We investigate the Hawking(-Unruh) effect for a real scalar field on the eternal black hole spacetime known as the RP geon. The Hartle-Hawking-like vacuum |0G〉 turns out to contain Boulware modes in correlated pairs, and operators that only couple to one member of each pair have thermal expectation values at the usual Hawking temperature. As both members of each correlated Boulware pair reside ...

We investigate dynamical instability of a two-dimensional quantum black hole model considered by Lowe in his study of Hawking evaporation. The model is supposed to express a black hole in equilibrium with a bath of Hawking radiation. It turns out that the model has at least one instability modes for a wide range of parameters, and thus it is unstable.

Applying Parikh’s semi-classical tunneling method, we consider Hawking radiation of the charged massive particles as a tunneling process from the Reissner-Nordströmde Sitter black hole with a global monopole. The result shows that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the radiant spectrum is not a pure thermal one, but is consistent with an underlying uni...

We present a short and direct derivation of Hawking radiation as a tunneling process, based on particles in a dynamical geometry. The imaginary part of the action for the classically forbidden process is related to the Boltzmann factor for emission at the Hawking temperature. Because the derivation respects conservation laws, the exact spectrum is no longer precisely thermal.