46,486 research outputs found

    Reactor Searches for Neutrino Magnetic Moment as a Probe of Extra Dimensions

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    We present calculations of the magnetic moment contribution to neutrino electron scattering in large extra dimension brane-bulk models (LED) with three bulk neutrinos. We discuss the cases with two and three large extra dimensions of sizes RR. The calculations are done using reactor flux from Uranium, 235U^{235}U as the neutrino source. We find that if the electron neutrino mass is chosen to be in the range of one eV, the differential cross section for νˉ−e\bar{\nu}-e scattering for low electron recoil energy can be of the same order as the presently explored values in reactor experiments. Furthermore the spectral shape for the LED models is different from the four dimensional case. Future higher precision reactor experiments can therefore be used to provide new constraints on a class of large extra dimension theories.Comment: 8 pages; 3 figure

    Relativity in space-times with short-distance structure governed by an observer-independent (Planckian) length scale

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    I show that it is possible to formulate the Relativity postulates in a way that does not lead to inconsistencies in the case of space-times whose short-distance structure is governed by an observer-independent length scale. The consistency of these postulates proves incorrect the expectation that modifications of the rules of kinematics involving the Planck length would necessarily require the introduction of a preferred class of inertial observers. In particular, it is possible for every inertial observer to agree on physical laws supporting deformed dispersion relations of the type E2−c2p2−c4m2+f(E,p,m;Lp)=0E^2- c^2 p^2- c^4 m^2 + f(E,p,m;L_p)=0, at least for certain types of ff.Comment: Same formulas and results as in 1st version, but a change of notation is introduced in order to clarify that the studied illustrative example is consistent with the R.P. for both choices of the overall sign. 1 ref added and 2 refs upgraded. Some rewording of the text in Sec5, and addition of an analogy with background fields in ordinary electromagnetism which I use to illustrate difference between space-times with an observer-independent Lp, and space-times in which Lp is introduced without modifications of Special Relativit

    A study of energy concentration and drain in incompressible fluids

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    In this paper we examine two opposite scenarios of energy behavior for solutions of the Euler equation. We show that if uu is a regular solution on a time interval [0,T)[0,T) and if u∈LrL∞u \in L^rL^\infty for some r≥2N+1r\geq \frac{2}{N}+1, where NN is the dimension of the fluid, then the energy at the time TT cannot concentrate on a set of Hausdorff dimension samller than N−2r−1N - \frac{2}{r-1}. The same holds for solutions of the three-dimensional Navier-Stokes equation in the range 5/3<r<7/45/3<r<7/4. Oppositely, if the energy vanishes on a subregion of a fluid domain, it must vanish faster than (T-t)^{1-\d}, for any \d>0. The results are applied to find new exclusions of locally self-similar blow-up in cases not covered previously in the literature.Comment: an update of the previous versio

    Semi-classical limit and minimum decoherence in the Conditional Probability Interpretation of Quantum Mechanics

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    The Conditional Probability Interpretation of Quantum Mechanics replaces the abstract notion of time used in standard Quantum Mechanics by the time that can be read off from a physical clock. The use of physical clocks leads to apparent non-unitary and decoherence. Here we show that a close approximation to standard Quantum Mechanics can be recovered from conditional Quantum Mechanics for semi-classical clocks, and we use these clocks to compute the minimum decoherence predicted by the Conditional Probability Interpretation.Comment: 8 pages, references adde

    Development of mainshaft seals for advanced air breathing propulsion systems, phase 1 Final report, 25 Jun. 1965 - 25 Jul. 1967

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    Comparison of gas film mainshaft seals with rubbing contract seals for high temperature, high speed, and high pressure gas turbine application

    Decoherence of Einstein-Podolsky-Rosen steering

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    We consider two systems A and B that share Einstein-Podolsky-Rosen (EPR) steering correlations and study how these correlations will decay, when each of the systems are independently coupled to a reservoir. EPR steering is a directional form of entanglement, and the measure of steering can change depending on whether the system A is steered by B, or vice versa. First, we examine the decay of the steering correlations of the two-mode squeezed state. We find that if the system B is coupled to a reservoir, then the decoherence of the steering of A by B is particularly marked, to the extent that there is a sudden death of steering after a finite time. We find a different directional effect, if the reservoirs are thermally excited. Second, we study the decoherence of the steering of a Schr\"odinger cat state, modeled as the entangled state of a spin and harmonic oscillator, when the macroscopic system (the cat) is coupled to a reservoir

    The Ammann-Beenker tilings revisited

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    This paper introduces two tiles whose tilings form a one-parameter family of tilings which can all be seen as digitization of two-dimensional planes in the four-dimensional Euclidean space. This family contains the Ammann-Beenker tilings as the solution of a simple optimization problem.Comment: 7 pages, 4 figure
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