We propose that space-time at the smallest scales is in reality a causal set: a locally finite set of elements endowed with a partial order corresponding to the macroscopic relation that defines past… Expand

We associate to any quantum field propagating in the background metric of a black hole an effective density matrix whose statistical entropy can be interpreted as a contribution to the total entropy… Expand

We derive a general quantum formula giving the mean-square displacement of a diffusing particle as a function of time. Near 0 K we find a universal logarithmic behavior (valid for times longer than… Expand

Lorentzian cobordism is considered as a mechanism for topology change in quantum gravity. It is shown that the condition for a topological cobordism to admit an appropriate metric is different in… Expand

It is customary, when discussing configuration spaces of identical particles in two or more dimensions, to discard the configurations where two or more particles overlap, the justification being that… Expand

A sufficient condition for the quantum entropy, $\ensuremath{-}\mathrm{Tr}(\ensuremath{\rho}\mathrm{ln}\ensuremath{\rho})$, to be nondecreasing under a tracepreserving positive linear map is that the… Expand

We isolated an unusual gram-negative organism, rarely considered a human pathogen, which appeared to cause peritonitis in one of our continuous ambulatory peritoneal dialysis patients. A 54-year-old… Expand

We point out that the putative Skyrme soliton in a simple chiral model of pions (without the Skyrme term) can be stabilized against collapse by quantum fluctuations. This leads to a reasonable… Expand