On the "Universal" Quantum Area Spectrum

There has been much debate over the form of the quantum area spectrum for a black hole horizon, with the evenly spaced conception of Bekenstein having featured prominently in the discourse. In this letter, we refine a very recently proposed method for calibrating the Bekenstein form of the spectrum. Our refined treatment predicts, as did its predecessor, a uniform spacing between adjacent spectral levels of $8\pi$ in Planck units; notably, an outcome that already has a pedigree as a proposed ``universal'' value for this intrinsically quantum-gravitational measure. Although the two approaches are somewhat similar in logic and quite agreeable in outcome, we argue that our version is conceptually more elegant and formally simpler than its precursor. Moreover, our rendition is able to circumvent a couple of previously unnoticed technical issues and, as an added bonus, translates to generic theories of gravity in a very direct manner.Comment: 7 Pages; (v2) now 9 full pages, significant changes to the text and material added but the general theme and conclusions are unchange

Gender differences in identities and their socio-structural correlates: how gendered lives shape parental and work identities

This study draws on identity theory to explore parental and work identities. It examined gender differences in identities, as well as the moderating role of gender in the effects of individuals’ socio-structural characteristics. A sample of 148 couples with young children completed extensive questionnaires. As hypothesized, couples’ paid work strategy moderated gender differences in the salience and centrality of parental and work identities. Whereas significant differences in identities were found between stay-at-home mothers and their breadwinning husbands, no differences were found among dual-earner couples. Moreover, men’s work identity centrality increased when they had more and younger children, whereas women’s work identity centrality decreased. Finally, men’s parental identity centrality increased with their income, whereas women’s parental identity centrality decreased the more they earned. These findings attest to the importance of examining differences within as well as between genders, by taking into account the interactive effects of gender with other socio-structural characteristics

Radiation via Tunneling from a de Sitter Cosmological Horizon

Hawking radiation can usefully be viewed as a semi-classical tunneling process that originates at the black hole horizon. The same basic premise should apply to de Sitter background radiation, with the cosmological horizon of de Sitter space now playing the featured role. In fact, a recent work [hep-th/0204107] has gone a long way to verifying the validity of this de Sitter-tunneling picture. In the current paper, we extend these prior considerations to arbitrary-dimensional de Sitter space, as well as Schwarzschild-de Sitter spacetimes. It is shown that the tunneling formalism naturally censors against any black hole with a mass in excess of the Nariai value; thus enforcing a ``third law'' of Schwarzschild-de Sitter thermodynamics. We also provide commentary on the dS/CFT correspondence in the context of this tunneling framework.Comment: 19 pages, Latex; citation added; Eqs.(36,37) correcte

Quantum Gravity and Recovery of Information in Black Hole Evaporation

The Generalized Uncertainty Principle (GUP), motivated by current alternatives of quantum gravity, produces significant modifications to the Hawking radiation and the final stage of black hole evaporation. We show that incorporation of the GUP into the quantum tunneling process (based on the null-geodesic method) causes correlations between the tunneling probability of different modes in the black hole radiation spectrum. In this manner, the quantum information becomes encrypted in the Hawking radiation, and information can be recovered as non-thermal GUP correlations between tunneling probabilities of different modes.Comment: 7 pages, no figure, final revisio

Anatomy of a Bounce

Holographic considerations are used in the scrutiny of a special class of brane-world cosmologies. Inherently to this class, the brane typically bounces, at a finite size, as a consequence of a charged black hole in the bulk. Whereas a prior treatment [hep-th/0301010] emphasized a brane that is void of standard-model matter, the analysis is now extended to include an intrinsic (radiation-dominated) matter source. An interesting feature of this generalized model is that a bounce is no longer guaranteed but, rather, depends on the initial conditions. Ultimately, we demonstrate that compliance with an appropriate holographic bound is a sufficient prerequisite for a bounce to occur.Comment: 14 pages, Revtex; (v2) minor revisions; (v3) reference adde

Of Bounces, Branes and Bounds

Some recent studies have considered a Randall-Sundrum-like brane world evolving in the background of an anti-de Sitter Reissner-Nordstrom black hole. For this scenario, it has been shown that, when the bulk charge is non-vanishing, a singularity-free ``bounce'' universe will always be obtained. However, for the physically relevant case of a de Sitter brane world, we have recently argued that, from a holographic (c-theorem) perspective, such brane worlds may not be physically viable. In the current paper, we reconsider the validity of such models by appealing to the so-called ``causal entropy bound''. In this framework, a paradoxical outcome is obtained: these brane worlds are indeed holographically viable, provided that the bulk charge is not too small. We go on to argue that this new finding is likely the more reliable one.Comment: 15 pages, Revtex; references added and very minor change

Area spectra versus entropy spectra in black holes in topologically massive gravity

We consider the area and entropy spectra of black holes in topologically massive gravity with gravitational Chern-Simons term. The examples we consider are the BTZ black hole and the warped AdS black hole. For the non-rotating BTZ black hole, the area and entropy spectra are equally spaced and independent of the coupling constant \v of the Chern-Simons term. For the rotating BTZ black hole case, the spectra of the inner and outer horizon areas are not equally spaced in general and dependent of the coupling constant \v. However the entropy spectrum is equally spaced and independent of the coupling constant \v. For the warped AdS black holes for $\v >1$ by using the quasinormal modes obtained without imposing the boundary condition at radial infinity we find again that the entropy spectrum is equally spaced and independent of the coupling constant \v, while the spectra of the inner and outer horizon areas are not equally spaced and dependent of the coupling constant \v. Our result implies that the entropy spectrum has a universal behavior regardless of the presence of the gravitational Chern-Simons term, and therefore it implies that the entropy is more `fundamental' than the horizon area.Comment: 16 page

On the Kerr Quantum Area Spectrum

Suppose that there is a quantum operator that describes the horizon area of a black hole. Then what would be the form of the ensuing quantum spectrum? In this regard, it has been conjectured that the characteristic frequencies of the black hole oscillations can be used to calibrate the spacing between the spectral levels. The current article begins with a brief review of this conjecture and some of its subsequent developments. We then suggest a simple but vital modification to a recent treatment on the Kerr (or rotating black hole) spectrum. As a consequence of this refinement, we are able to rectify a prior inconsistency (as was found between two distinct calculations) and to establish, unambiguously, a universal form for the Kerr and Schwarzschild spectra.Comment: Roughly 8 pages; (v2) added references and very minor change

Exact braneworld cosmology induced from bulk black holes

We use a new, exact approach in calculating the energy density measured by an observer living on a brane embedded in a charged black hole spacetime. We find that the bulk Weyl tensor gives rise to non-linear terms in the energy density and pressure in the FRW equations for the brane. Remarkably, these take exactly the same form as the ``unconventional'' terms found in the cosmology of branes embedded in pure AdS, with extra matter living on the brane. Black hole driven cosmologies have the benefit that there is no ambiguity in splitting the braneword energy momentum into tension and additional matter. We propose a new, enlarged relationship between the two descriptions of braneworld cosmology. We also study the exact thermodynamics of the field theory and present a generalised Cardy-Verlinde formula in this set up.Comment: 17 pages, no figures; v3: Minor change, References added, Version to appear in CQ

The Highly Damped Quasinormal Modes of dd-dimensional Reissner-Nordstrom Black Holes in the Small Charge Limit

We analyze in detail the highly damped quasinormal modes of $d$-dimensional Reissner-Nordstr$\ddot{\rm{o}}$m black holes with small charge, paying particular attention to the large but finite damping limit in which the Schwarzschild results should be valid. In the infinite damping limit, we confirm using different methods the results obtained previously in the literature for higher dimensional Reissner-Nordstr$\ddot{\rm{o}}$m black holes. Using a combination of analytic and numerical techniques we also calculate the transition of the real part of the quasinormal mode frequency from the Reissner-Nordstr$\ddot{\rm{o}}$m value for very large damping to the Schwarzschild value of $\ln(3) T_{bh}$ for intermediate damping. The real frequency does not interpolate smoothly between the two values. Instead there is a critical value of the damping at which the topology of the Stokes/anti-Stokes lines change, and the real part of the quasinormal mode frequency dips to zero.Comment: 18 pages, 8 figure