In some respects the black hole plays the same role in gravitation that the atom played in the nascent quantum mechanics. This analogy suggests that black hole mass M might have a discrete spectrum.â€¦ (More)

Yet if we have learned anything from engineering, biology and physics, information is just as crucial an ingredient. The robot at the automobile factory is supplied with metal and plastic but canâ€¦ (More)

We develop the idea that, in quantum gravity where the horizon fluctuates, a black hole should have a discrete mass spectrum with concomitant line emission. Simple arguments fix the spacing of theâ€¦ (More)

The appearance of two geometries in a single gravitational theory is familiar. Usually, as in the Brans-Dicke theory or in string theory, these are conformally related Riemannian geometries. Is thisâ€¦ (More)

A naive view of physicsâ€”classical or quantumâ€”would have us believe that an infinite amount of information can be contained in a finite 3-D space. After all, matter can have an infinity of classicalâ€¦ (More)

Information must take up space, must weigh, and its flux must be limited. Quantum limits on communication and information storage leading to these conclusions are here described. Quantum channelâ€¦ (More)

The adiabatic invariant nature of black hole horizon area in classical gravity suggests that in quantum theory the corresponding operator has a discrete spectrum. I here develop further an algebraicâ€¦ (More)

The holographic bound that the entropy (log of number of quantum states) of a system is bounded from above by a quarter of the area of a circumscribing surface measured in Planck areas is widelyâ€¦ (More)

The question of Super-luminal (V 2 > c 2) objects or waves has a long story, starting perhaps in 50 b.C. with Lucretius' De Rerum Natura (cf., e.g., book 4, line 201: [<<Quone vides citius debere etâ€¦ (More)