Quantum Raychaudhuri equation

We compute quantum corrections to the Raychaudhuri equation, by replacing classical geodesics with quantal (Bohmian) trajectories, and show that they prevent focusing of geodesics, and the formation of conjugate points. We discuss implications for the Hawking-Penrose singularity theorems, and for curvature singularities.Comment: Section on singularity theorems revised. To appear in Phys. Rev. D. 4 pages, revte

Cosmic coincidence or graviton mass?

Using the quantum corrected Friedmann equation, obtained from the quantum Raychudhuri equation, and assuming a small mass of the graviton (but consistent with observations and theory), we propose a resolution of the smallness problem(why is observed vacuum energy so small?) and the coincidence problem(why does it constitute most of the universe, about 70%, in the current epoch?).Comment: This essay received an Honorable Mention in the 2014 Gravity Research Foundation Essay Competition. 2 pages, revtex4. arXiv admin note: text overlap with arXiv:1404.309

Comments on "Schwinger's Model of Angular Momentum with GUP" by H. Verma et al, arXiv:1808.00766

In this note, we show that the methodology and conclusions of "Schwinger's Model of Angular Momentum with GUP" [arxiv:1808.00766] are flawed and that the conclusions of "Generalized Uncertainty Principle and angular momentum" (P. Bosso and S. Das) [arxiv:1607.01083] remain valid.Comment: 3 page

Black Hole Emission Rates and the AdS/CFT Correspondence

We study the emission rates of scalar, spinor and vector particles from a 5 dimensional black hole for arbitrary partial waves. The solution is lifted to 6 dimensions, and the near horizon $BTZ \times S^3$ geometry of the black hole solution is probed to determine the greybody factors. We show that the exact decay rates can be reproduced from a $(1+1)$-dimensional conformal field theory which lies on the boundary of the near horizon geometry. The AdS/CFT correspondence is used to determine the dimension of the CFT operators corresponding to the bulk fields. These operators couple to plane waves incident on the CFT from infinity to produce emission in the bulk.Comment: 37 pages, minor modifications; to be published in JHE

How classical are TeV-scale black holes?

We show that the Hawking temperature and the entropy of black holes are subject to corrections from two sources: the generalized uncertainty principle and thermal fluctuations. Both effects increase the temperature and decrease the entropy, resulting in faster decay and ``less classical'' black holes. We discuss the implications of these results for TeV-scale black holes that are expected to be produced at future colliders.Comment: 10 pages, no figures, REVTeX style. Extra comments and references to match version accepted to Classical and Quantum Gravit