Can gravitational spin-spin interaction really balance two Curzon masses?

Curzon's bipolar solution as written in Weyl coordinates by Dietz and Hoenselaers (more specifically, the expression of γ₀) for the seed metric is shown to be incompatible with the axis specifications and eventually invalidates the conclusion that two spinning Curzon masses do balance. The genesis of the subtle error of Dietz and Hoenselaers will also be evident from our analysis.     

Is gravitational mass of a composite quantum body equivalent to its energy?

We define passive gravitational mass operator of a hydrogen atom in the post-Newtonian approximation of general relativity and show that it does not commute with energy operator, taken in the absence of gravitational field. Nevertheless, the equivalence between the expectation values of passive gravitational mass and energy is shown to survive for stationary quantum states. Inequivalence between passive gravitational mass and energy at a macroscopic level results in time dependent oscillations of the expectation values of passive gravitational mass for superpositions of stationary quantum states, where the equivalence restores after averaging over time. Inequivalence between gravitational mass and energy at a microscopic level reveals itself as unusual electromagnetic radiation, emitted by the atoms, supported and moved in the Earth gravitational field with constant velocity using spacecraft or satellite, which can be experimentally measured.     

What is a mean gravitational field?

The equations of General Relativity are non-linear. This makes their averaging non-trivial. The notion of mean gravitational field is defined and it is proven that this field obeys the equations of General Relativity if the unaveraged field does. The workings of the averaging procedure on Maxwells field and on perfect fluids in curved space-times are also discussed. It is found that Maxwells equations are still verified by the averaged quantities but that the equation of state for other kinds of matter generally changes upon average. In particular, it is proven that the separation between matter and gravitational field is not scale-independent. The same result can be interpreted by introducing a stress-energy tensor for a mean-vacuum. Possible applications to cosmology are discussed. Finally, the work presented in this article also suggests that the signature of the metric might be scale-dependent too.Received: 16 October 2003, Published online: 15 March 2004PACS: 04.20.Cv Fundamental problems and general formalism 04.40.Nr Einstein-Maxwell spacetimes, spacetimes with fluids, radiation or classical fields - 95.35. + d Dark matter (stellar, interstellar, galactic, and cosmological)     

Is strong gravitational radiation predicted by TeV gravity?

In TeV-gravity models, the gravitational coupling to particles with energies ∼ m _Pl ∼ 10 TeV is not suppressed by powers of ultra-small ratio /M _Pl with M _Pl ∼ 10¹⁹ GeV. Therefore, one could imagine strong synchrotron radiation of gravitions by the accelerating particles to become the most pronounced manifestation of TeV-gravity at LHC. However, this turns out to be not true: considerable damping continues to exist, only the place of /M _Pl is taken by a power of a ratio ϑω/ , where the typical frequency ω of emitted radiation, while increased by a number of γ-factors, cannot reach /ϑ unless particles are accelerated by nearly critical fields. Moreover, for currently available magnetic fields B ∼ 10 T, multidimensionality does not enhance gravitational radiation at all even if TeV-gravity is correct. The text was submitted by the authors in English.     

Is a system's wave function in one-to-one correspondence with its elements of reality?

Although quantum mechanics is one of our most successful physical theories, there has been a long-standing debate about the interpretation of the wave function--the central object of the theory. Two prominent views are that (i) it corresponds to an element of reality, i.e., an objective attribute that exists before measurement, and (ii) it is a subjective state of knowledge about some underlying reality. A recent result [M.?F. Pusey, J. Barrett, and T. Rudolph, arXiv:1111.3328] has placed the subjective interpretation into doubt, showing that it would contradict certain physically plausible assumptions, in particular, that multiple systems can be prepared such that their elements of reality are uncorrelated. Here we show, based only on the assumption that measurement settings can be chosen freely, that a system's wave function is in one-to-one correspondence with its elements of reality. This also eliminates the possibility that it can be interpreted subjectively.     

Is the weak interaction constant really constant?

A comparison is made of the probability of the process of two-neutrino double beta decay for ⁸²Se and ⁹⁶Zr in direct (counter) and geochemical experiments. The experimental data for ¹³⁰Te are also analyzed. It is shown that the probability is systematically lower in geochemical experiments, which characterize the probability of (2) decay 10⁹ y ago. It is proposed that this could be due to a change in the weak interaction constant with time. It is proposed that a series of new, precise measurements be performed with the aid of counters and geochemical experiments.     

Is the quantum Hall effect influenced by the gravitational field?

Most of the experiments on the quantum Hall effect (QHE) were made at approximately the same height above sea level. A future international comparison will determine whether the gravitational field g(x) influences the QHE. In the realm of (1+2)-dimensional phenomenological macroscopic electrodynamics, the Ohm-Hall law is metric independent ("topological"). This suggests that it does not couple to g(x). We corroborate this result by a microscopic calculation of the Hall conductance in the presence of a post-Newtonian gravitational field.     

Charm in PHENIX—a signal or a background?

Charm, as well as Strangeness, plays an important role in searches for the Quark Gluon Plasma.J/Φ Suppression and Strangeness Enhancement are two of the earliest proposed QGP signatures. Recent theoretical work on charm in Relativistic Heavy Ion collisions has focussed on di-lepton production. However, even before the discovery of theJ/Ψ, evidence of open charm was seen in hadron collisions via the observation of promptsingle leptons “resulting from the semi-leptonic decays of charm particles.” [1] The ‘copious’ yield of direct (i.e. not from Dalitz decays) single electrons and muons—at a levele/π～10^?4 forpT≥1.3 GeV/c—observed in the early 1970’s was explained by Hinchliffe and Llewellyn-Smith and Bourquin and Gaillard as evidence of open-charm production. It is likely thate/π at RHIC is large and is a good measure of charm production. Thus, a measurement of single electrons with moderatepT>1.5 GeV/c at RHIC should give a clean charm signal in heavy ion collisions,with no combinatoric background.     

A special form of electrodynamical response to a gravitational wave：outgoing and imploding photon fluxes

We have investigated the interaction of an electromagnetic (EM) wave with a standing gravitational wave (GW) in an external static magnetic field,and obtained concrete forms of first-order perturbative EM energy fluxes.Unlike the propagating properties of the “left-circular” and “right-circular” waves of the tangential perturbative energy fluxes around the symmetrical axis,the radial perturbative energy fluxes are expressed as the outgoing and imploding waves to the symmetrical axis.We also examine several physical examples and show that this effect can produce very small but nonvanishing radial perturbative photon fluxes.This may be useful for EM detection of the high-frequency relic GWs of the GHz region in quintessential inflationary models.     

Is the “missing mass” really missing?

We have no experimental evidence for the validity of the inverse square law for gravitation at distances significantly larger than the diameter of the solar system. This raises the very real possibility that the missing mass (dark matter) may not exist. Instead, the inverse square law may be breaking down at distances of the order of tens of kiloparsecs. I discuss this possibility within the framework of Scalar-Vector-Tensor (SVT) theories of gravity. It appears to be relatively easy to account for up to approximately 10% of the galactic halo dark matter via SVT theories of gravity. With some fine-tuning of parameters, it is conceivable that all of the dark matter can be accounted for in this way.This essay received an honorable mention from the Gravity Research Foundation for the year 1987.Supported by the U.S. Department of Energy under grant #DE-FG03-84ER-40168.     

Gauge-invariant gravitational wave modes in pre-big bang cosmology

The t<0 branch of pre-big bang cosmological scenarios is subject to a gravitational wave instability. The unstable behaviour of tensor perturbations is derived in a very simple way in Hwang’s covariant and gauge-invariant formalism developed for extended theories of gravity. A simple interpretation of this instability as the effect of an “antifriction” is given, and it is argued that a universe must eventually enter the expanding phase.     

Bimodality as a signal of a liquid-gas phase transition in nuclei?

We use the heavy-ion phase-space exploration model to discuss the origin of the bimodality in charge asymmetry observed in nuclear reactions around the Fermi energy. We show that it may be related to the important angular momentum (spin) transferred into the quasiprojectile before secondary decay. As the spin overcomes the critical value, a sudden opening of decay channels is induced and leads to a bimodal distribution for the charge asymmetry. In the model, it is not assigned to a liquid-gas phase transition but to specific instabilities in nuclei with high spin. Therefore, we propose to use these reactions to study instabilities in rotating nuclear droplets.