Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userBrief reply to Can gravity account for the emergence of classicality?
140
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
In a series of comments, Bonder et al. criticized our work on decoherence due to time dilation [Nature Physics 11, 668-672 (2015)]. First the authors erroneously claimed that our results contradict the equivalence principle, only to resolve the alleged conflict in a second note. The resolution - relativity of simultaneity - was already explained in our reply [arXiv:1508.03296], which Bonder et al. now essentially reiterate. The newly raised points were also already extensively clarified in our note. The physical prediction of our work remains valid: systems with internal dynamics decohere if the superposed paths have different proper times.
rate research
Read More
After short historical overview we describe the difficulties with application of standard QFT methods in quantum gravity (QG). The incompatibility of QG with the use of classical continuous space-time required conceptually new approach. We present briefly three proposals: loop quantum gravity (LQG), the field-theoretic framework on noncommutative space-time and QG models formulated on discretized (triangularized) space-time. We evaluate these models as realizing expected important properties of QG: background independence, consistent quantum diffeomorphisms, noncommutative or discrete structure of space-time at very short distances, finite/renormalizable QG corrections. We only briefly outline an important issue of embedding QG into larger geometric and dynamical frameworks (e.g. supergravity, (super)strings, p-branes, M-theory), with the aim to achieve full unification of all fundamental interactions.
J. W. Moffat and V. T. Toth submitted recently a comment (arXiv:0903.5291) on our latest paper Modified scalar-tensor-vector gravity theory and the constraint on its parameters [Deng, et al., Phys. Rev. D 79, 044014 (2009); arXiv:0901.3730 ]. We reply to each of their comments and justify our work and conclusions. Especially, their general STVG (MOG) theory has to be modified to fit the modern precision experiments.
In most theories of gravity involving torsion, the source for torsion is the intrinsic spin of matter. Since the spins of fermions are normally randomly oriented in macroscopic bodies, the torsion generated is normally negligible. However, in a recent paper, Mao et al. point out that there is a class of theories in which the angular momentum of macroscopic spinning bodies generates a significant amount of torsion. They argue that by the principle of action equals reaction, one would expect the angular momentum of test bodies to couple to a background torsion field, and therefore the precession of the GPB gyroscopes should be affected in these theories by the torsion generated by the Earth. We show that in fact the principle of action equals reaction does not apply to these theories. We examine in detail a generalization of the Hayashi-Shirafuji theory suggested by Mao et al. called Einstein-Hayashi-Shirafuji theory. There are a variety of differe
A striking feature of our fundamentally indeterministic quantum universe is its quasiclassical realm -- the wide range of time place and scale in which the deterministic laws of classical physics hold. Our quasiclassical realmis an emergent feature of the fundamental theories of our universes quantum state and dynamics. There are many types of quasiclassical realms our Universe could exhibit characterized by different variables, different levels of coarse-graining, different locations in spacetime, different classical physics, and different levels of classicality.We propose a measure of classicality for quasiclassical realms, We speculate on the observable consequences of different levels of classicality especially for information gathering and utilizing systems (IGUSes) such ourselves as observers of the Universe.
It is well known that the Klein-Gordon equation in curved spacetime is conformally noninvariant, both with and without a mass term. We show that such a noninvariance provides nontrivial physical insights at different levels, first within the fully relativistic regime, then at the nonrelativistic regime leading to the Schrodinger equation, and then within the de Broglie-Bohm causal interpretation of quantum mechanics. The conformal noninvariance of the Klein-Gordon equation coupled to a vector potential is confronted with the conformal invariance of Maxwells equations in the presence of a charged current. The conformal invariance of the non-minimally coupled Klein-Gordon equation to gravity is then examined in light of the conformal invariance of Maxwells equations. Finally, the consequence of the noninvariance of the equation on the Aharonov-Bohm effect in curved spacetime is discussed. The issues that arise at each of these different levels are thoroughly analyzed.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
