16163396
Lightcone fluctuations in quantum gravity and extra dimensions
Abstract We discuss how compactified extra dimensions may have potentially observable effects which grow as the compactification scale decreases. This arises because of lightcone fluctuations in the uncompactified dimensions which can result in the broadening of the spectral lines from distant sources. We analyze this effect in a five dimensional model, and argue that data from gamma ray burst sources require the compactification length to be greater than about 105 cm in this model.
119090796
Fulling–Davies–Unruh effect and spontaneous excitation of an accelerated atom interacting with a quantum scalar field
Abstract We investigate, from the point of view of a coaccelerated frame, the spontaneous excitation of a uniformly accelerated two-level atom interacting with a scalar field in a thermal state at a finite temperature T and show that the same spontaneous excitation rate for the uniformly accelerated atom in the Minkowski vacuum obtained in the inertial frame can only be recovered in the coaccelerated frame assuming a thermal bath at the Fulling–Davies–Unruh temperature T FDU = a / 2 π for what appears to be the Minkowski vacuum to the inertial observer. Our discussion provides another example of a physical process different from those examined before in the literature to better understand the Fulling–Davies–Unruh effect.
115459673
LIGHTCONE FLUCTUATIONS AND EXTRA DIMENSIONS
118525095
Lamb shift for static atoms outside a Schwarzschild black hole
We study, by separately calculating the contributions of vacuum fluctuations and radiation reaction to the atomic energy level shift, the Lamb shift of a static two-level atom interacting with real massless scalar fields in the Boulware, Unruh, and Hartle-Hawking vacuums outside a Schwarzschild black hole. We find that in the Boulware vacuum, the Lamb shift gets a correction arising as a result of the backscattering of vacuum field modes off the space-time curvature, which is reminiscent of the correction to the Lamb shift induced by the presence of cavities. However, when the Unruh and Hartle-Hawking vacua are concerned, our results show that the Lamb shift behaves as if the atom were irradiated by a thermal radiation or immersed in a thermal bath at the Hawking temperature, depending on whether the scalar field is in the Unruh or the Hartle-Hawking vacuum. Remarkably, the thermal radiation is always backscattered by the space-time geometry.
119124346
Unruh effect and entanglement generation for accelerated atoms near a reflecting boundary
We study, in the framework of open systems, the entanglement generation of two independent uniformly accelerated atoms in interaction with the vacuum fluctuations of massless scalar fields subjected to a reflecting plane boundary. We demonstrate that, with the presence of the boundary, the accelerated atoms exhibit distinct features from static ones in a thermal bath at the corresponding Unruh temperature in terms of the entanglement creation at the neighborhood of the initial time. In this sense, accelerated atoms in vacuum do not necessarily have to behave as if they were static in a thermal bath at the Unruh temperature.
120986058
Quantum thermal aspects of uniformly accelerating charged black holes
121187481
A test of the glueball theory for the ξ(2230)
Abstract The possibility that the ξ(2230) is considered as a glueball is discussed in the framework of a nonrelativistic potential model [D. Robson, Nucl. Phys. B 130 (1977) 328] of the glueball with massive constituent gluons by using the experimental data from the Mark III Collaboration. The ratios of the helicity amplitude are calculated. The results are that the theoretical values cannot be consistent with the data if the ξ(2230) is a 2 ++ glueball in a pure S wave and the theoretical values are in excellent agreement with the data if the ξ(2230) is a 2 ++ glueball in a mixture between the S wave and two D waves or a 4 ++ glueball in a pure D wave.
123559303
DIGITAL ORIGIN OF COSMIC INFLATION
Assuming our physical universe processes and registers information to determine its dynamical evolution, one can put serious constraints on the cosmology that our universe can bear, in particular, the origin of cosmic inflation. The universe evolves to gain her computation capacity which is linear in time t. On the other hand, the growth in content of degrees of freedom (i.e. by integrating in more galaxies) is as t3/2 through expansion. When the in flux of degrees of freedom of the universe grows beyond some value, the computation capacity of the universe becomes insufficient to determine its evolution, the universe fixes its Hubble radius and inflates away its degrees of freedom within its horizon to regain dynamical evolution. The length of inflation is determined by the communication time required by the universe to become aware of the dropping in the degrees of freedom below some critical value by inflation and is proportional to its Hubble radius. We predict that there can be multiple cosmic inflations. The next inflation era will stop after inflating for a period of 1019 sec if the past inflation period of our universe was 10-33 sec.
109933831
New formulation of Horava–Lifshitz quantum gravity as a master constraint theory
Abstract Both projectable and non-projectable versions of Horava–Lifshitz gravity face serious challenges. In the non-projectable version, the constraint algebra is seemingly inconsistent. The projectable version lacks a local Hamiltonian constraint, thus allowing for an extra scalar mode which can be problematic. A new formulation of non-projectable Horava–Lifshitz gravity, naturally realized as a representation of the master constraint algebra studied by loop quantum gravity researchers, is presented. This yields a consistent canonical theory with first class constraints. It captures the essence of Horava–Lifshitz gravity in retaining only spatial diffeomorphisms (instead of full space–time covariance) as the physically relevant non-trivial gauge symmetry; at the same time the local Hamiltonian constraint needed to eliminate the extra mode is equivalently enforced by the master constraint.
120072882
Quarkonia-Glueball Structure of the Ground Pseudoscalar Mesons
Considering corrections due to SU(3) flavor symmetry breaking, non-ideal ω - ϕ mixing, double OZI and electromagnetic amplitudes of J/ψ decays into a vector and a pseudo-scalar meson, and three-gluon-annihilation amplitudes of radiative decays of J/ψ into a pseudoscalar meson, we investigate two-photon decays of pseudoscalar mesons, radiative decays between pseudoscalar and vector mesons, decays of J/ψ into a vector and a pseudoscalar meson, and radiative decays of J/ψ into a pseudoscalar meson. The quarkonia-glueball structure of η, η′ and η(1440) is phenomenologically deduced from the fit to the updated world average data concerning the above mentioned decays. We find that η (η′) contains about 48.7%, 47.6%, 3.7% (32.9%, 48.8%, 18.3%) non-strange quarkonium, strange quarkonium and glueball components, respectively, and that η(1410) is mainly a glueball state (about 78% glueball component), mixed with 18.5% non-strange quarkonium and 3.5% strange quarkonium. We predict that Br(J/ψ→γη) : Br(J/ψ→γη′) : Br (J/ψ→γη(1410)) = 1.0:5.2:8.0, which can be tested at BEPC/BES with 50 million J/ψ events.
122878082
Induced Topological Terms, Hidden Local Symmetry, and Anyon Superconductivity
We show how the topological Chern-Simons term in three dimensions and the θ-term, in four dimensions can be dynamically generated due to quantum fluctuations in Nambu-Jona-Lasinio models. These results give a vivid demonstration of hidden local symmetry at work. The fluctuation-induced Chern-Simons term provides a natural way to incorporate fractional statistics and thus a more direct connection with anyon superconductivity. Possible phenomenological implications of this approach in particle physics are also discussed.