Unique Quantum Paths by Continuous Diagonalization of the Density Operator

In this short note we show that for a Markovian open quantum system it is always possible to construct a unique set of perfectly consistent Schmidt paths, supporting quasi-classicality. Our Schmidt process, elaborated several years ago, is the $\Delta t\to 0$ limit of the Schmidt chain constructed very recently by Paz and Zurek.Comment: 8 pages REVTe

Note on Possible Emergence Time of Newtonian Gravity

If gravity were an emergent phenomenon, some relativistic as well as non-relativistic speculations claim it is, then a certain emergence time scale tau_? would characterize it. We argue that the available experimental evidences have poor time resolution regarding how immediate the creation of Newton field of accelerated mass sources is. Although the concrete theoretical model of gravity's `laziness' is missing, the concept and the scale tau_? ~ 1ms, rooted in an extrapolation of spontaneous wave function collapse theory, might be tested directly in reachable experiments.Comment: 2pp, essentially revised, clarified, concretized version accepted in PL

Calculation of X-Ray Signals from Karolyhazy Hazy Space-Time

Karolyhazy's hazy space-time model, invented for breaking down macroscopic interferences, employs wave-like gravity disturbances. If so, then electric charges would radiate permanently. Here we discuss the observational consequences of the radiation. We find that such radiation is excluded by common experimental situations.Comment: 7 pages, PlainTe

Quantum linear Boltzmann equation with finite intercollision time

Inconsistencies are pointed out in the usual quantum versions of the classical linear Boltzmann equation constructed for a quantized test particle in a gas. These are related to the incorrect formal treatment of momentum decoherence. We prove that ideal collisions would result in complete momentum decoherence, the persistence of coherence is only due to the finite intercollision time. A corresponding novel quantum linear Boltzmann equation is proposed.Comment: 5p

Comments on "Objectification of classical properties induced by quantum vacuum fluctuations"

We argue that in standard quantum electrodynamics radiative corrections do not lead to decoherence of unexcited atomic systems. The proposal of Santos relies upon deliberate switching on and off the vacuum interactions.Comment: 4 pages Latex, 21-June-199

The gravity-related decoherence master equation from hybrid dynamics

Canonical coupling between classical and quantum systems cannot result in reversible equations, rather it leads to irreversible master equations. Coupling of quantized non-relativistic matter to gravity is illustrated by a simplistic example. The heuristic derivation yields the theory of gravity-related decoherence proposed longtime ago by Penrose and the author.Comment: 9pp, extended version of invited talk at Fifth International Workshop DICE2010 (Castello Pasquini/Castiglioncello/Tuscany, Sept. 13-17, 2010

Equation and test of possible delay time of Newton force

Recently, a simple heuristic modification of the Newton potential with a non-zero delay-time $\tau_G$ has been proposed. Our modification is largely suppressed for purely gravitational interactions, it becomes relevant under non-gravitational accelerations of the sources. We illustrate how the choice $\tau_G\sim1$ms may already influence the 5th digit of G determined by Cavendish experiments. Re-evaluation of old Cavendish experiments and implementing slightly modified new ones may confirm the proposal or, at least, put a stronger upper limit on $\tau_G$.Comment: 4 pp, 2 figs, based on talk at Int. Symp. Wigner 111 - Colourful & Deep (Budapest, 11-13 Nov, 2013