1,721,221 research outputs found
Broken Lorentz invariance and metric description of interactions in a deformed Minkowski space
No full textWe discuss the possible breakdown of Lorentz invariance-at distances greater than the planck length-from both the theoretical and the phenomenological point of view. The theoretical tool to deal with such a problem is provided by a "deformation" of the Minkowski metric, with parameters dependent on the energy of the physical system considered. Such a deformed metric realizes, for any interaction, the "solidarity principle" between interactions and spacetime geometry (usually assumed for gravitation), according to which the peculiar features of every interaction determine locally-its own spacetime structure. The generalized theory of relativity, based on the locally deformed Minkowski spacetime, is called "deformed special relativity" (DSR). In the first part of the paper, we give the foundations and the basic laws of DSR. In the second part, we analyse some experimental data, which admit an interpretation in terms of the DSR formalism and are, therefore, candidates for displaying a breakdown of the Lorentz symmetry. They are (i) the superluminal propagation of evanescent electromagnetic waves in waveguides, (ii) the meanlife of the K-S(n). (iii) the Bose-Einstein correlation in pion production and (iv) the comparison of clock rates in the gravitational field of Earth. Such analysis provides us with the explicit forms of the related deformed metrics as functions of the energy, thus putting in evidence, in all four cases (and therefore for all four fundamental interactions), departures from the usual Minkowski metric. This preliminary evidence for a broken Lorentz invariance may be regarded as the signature of possible nonlocal effects involved in the processes examined. Moreover the corresponding deformed metrics obtained by our analysis provide as effective dynamical description of the interactions (at least in the energy range considered)
Energy-dependent metric for gravitation from clock-rate experiments
No full textWe carry out a detailed analysis of the data on the comparison of clock rates between a flying dock and a clock at ground, performed by Alley and co-workers at the end of 1970's. The fit to such data is in favor of an energy-dependent metric for gravitation, whose time coefficient is at variance with the standard Einsteinian one in the weak-field approximation. By exploiting the formalism of a deformed Minkowski space-time, with metric coefficients dependent on the energy, we show that a possible lower limit on the propagation speed of gravitational effects is about 10(10)c, in agreement with a recent analysis by Van Flandern based on the acceleration of binary systems
Energy-dependent phenomenological metrics and five-dimensional Einstein equations
No full textWe propose a new Kaluza-Klein-like scheme based on a five-dimensional Riemannian space in which energy plays the role of the fifth dimension and spacetime is deformed. The solutions of the five-dimensional Einstein equations in vacuum allow us to recover, as special cases, the energy-dependent phenomenological metrics, describing the four fundamental interactions, recently derived from the analysis of some experimental data
Toward a metric description of hadronic interaction from Bose-Einstein correlation
No full textWe discuss the problem of second-order correlation in pion production in high-energy processes (commonly known as Bose-Einstein correlation) by means of the concept of nonlocality and its mathematical realization via the isotopy of Hilbert and Minkowski spaces. Such a nonlocal approach allows one to describe the spatial shape of the source when: pions are produced (>), and to account also for the correlation in phase. The correlation function obtained by this method does not contain free > parameters. Moreover, the test of this nonlocal correlation function, performed an the UA1 experimental data, is as good as that given by the conventional treatment. Such an approach suggests an interpretation of the pion production as a decay process of the fireball, whose > is explicitly evaluated. Using the data of the UA1 ramping run, we find the expression of the metric parameters as functions of the energy. They provide an effective dynamical description of the hadronic interaction in terms of a deformation of the Minkowski metric. The related parameters of the fireball admit of future experimental verification at DELPHI. The law of deformation of time in presence of a hadronic field is derived. Its behaviour with the energy allows one to give an appealing picture of confinement and asymptotic freedom of hadronic constituents
A unified view to Cologne and Florence experiments on superluminal photon propagation
No full textWe show that two of the first performed experiments on superluminal photon propagation, namely,,the 1992 Cologne experiment on the tunneling of evanescent waves in an undersized waveguide, and the 1993 Florence experiment on the microwave propagation in vacuum between two horn antennas, do admit a common interpretation. Precisely, both experimental devices behave as a high-pass filter. We get this result by two different methods, one based on the Friis law (which yields the efficiency of a transmitting device), and the other on the deformation of the Minkowski space-time. This allows us to set intriguing connections between these two (a priori different) classes of experiments. In particular, in either case the superluminal propagation can be described as a tunneling and is related to evanescent waves. (C) 2002 Elsevier Science B.V. All rights reserved
The shadow of light: Challenging classical and quantum electrodynamics
No full textWe review some optical experiments, carried out in the last decade, which evidence an anomalous behavior of photon systems. Their results are apparently at variance with both standard quantum mechanics (in the Copenhagen interpretation) and usual (classical and quantum) electrodynamics. In particular, they can be interpreted as a virtual interference involving the pilot waves associated to photons (according to Bohmian quantum mechanics). The anomalous effects exhibit a threshold behavior in energy and space, which agrees with results obtained on the electromagnetic breakdown of local Lorentz invariance. A possible connection between these seemingly unrelated implications of the observed phenomenon can be set by assuming that the pilot wave of a photon is a deformation of spacetime ("shadow of light")
Observation of a DC voltage induced by a steady magnetic field: A possible electromagnetic breakdown of Lorentz invariance?
No full textA recently proposed electromagnetic test of the breakdown of local Lorentz invariance, based on the detection of a nonzero force between a circular stationary current and a charge (both at rest in the Earth frame), has provided positive evidence for such an effect. We analyze in detail the experimental results obtained, together with their implications. Possible theoretical interpretations are briefly discussed. It is shown that the corresponding values found for the parameters of Lorentz invariance violation are consistent with the existing upper limits
Energy-dependent description of gravitation supported by an electromagnetic test of local Lorentz invariance
No full textWe put forward a possible intriguing connection between an energy-dependent metric for gravitation (obtained by fitting the data on the slowing down of clocks in the gravitational field of Earth) and the positive experimental results of a recently proposed electromagnetic test of breakdown of local Lorentz invariance, based on the detection of a voltage induced by a steady magnetic field
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