Modern Physics Letters A

The role of time has changed conceptually moving from classical Newtonian physics to general relativity and is one of the main obstacles avoiding a clear unification between a covariant quantum mechanics theory and a theory of gravity. In quantum mechanics as in Newtonian physics, time is an evolutional causal parameter, while in general relativity, time has become a spatial axis where matter is spread over the whole world line (an unlocalized 4D wave function), and the 4D picture became a static picture where our empirical experience of dynamics is merely an illusion of our minds. Understanding that Newtonian time still exists in parallel to the 4D world, raises the possibility to describe gravity within a manifestly covariant quantum theory. The examples of the use of such a theory raise the possibility of a clear interpretation of recent interference in time experiments, and also raise new physics when dealing with a curved spacetime.

In this paper we consider the most general field equations for a system of two fermions of which one single-handed, showing that the spin-torsion interactions among these spinors have a structure identical to that of the electroweak forces among leptons; possible extensions are discussed.

Gravitational and electroweak interactions can be unified in analogy with the unification in the Weinberg–Salam theory. The Yang–Mills framework is generalized to include spacetime translational group T(4), whose generators T_μ ( = ∂/∂x^μ) do not have constant matrix representations. By gauging T(4) × SU(2) × U(1) in flat spacetime, we have a new tensor field ϕ_μν which universally couples to all particles and anti-particles with the same constant g, which has the dimension of length. In this unified model, the T(4) gauge symmetry dictates that all wave equations of fermions, massive bosons and the photon in flat spacetime reduce to a Hamilton–Jacobi equation with the same "effective Riemann metric tensor" in the geometric-optics limit. Consequently, the results are consistent with experiments. We demonstrated that the T(4) gravitational gauge field can be quantized in inertial frames.

We calculate the static Wilson loop from string/gauge correspondence to obtain the potential in nonrelativistic quantum field theory, i.e. CFT with Galilean symmetry. We analyze the convexity conditions¹³ for potential in this theory, and obtain restrictions for the acceptable dynamical exponent z.

In this paper, we present a special Lorentzian metric to solve the vacuum Einstein's field equation with cosmological constant Λ and get a general form of solution. By some proper coordinate transformations, a degenerate static vacuum solution of class A with cosmological constant is obtained, and the corresponding one of class B can also be obtained by the complex transformation. We show that this is a constructive and effective new method to extend the degenerate static vacuum solution to the case with cosmological constant.

This paper deals with the dynamical behavior of phantom field near five-dimensional charged black hole. We formulate equations of motion for steady-state spherically symmetric flow of phantom fluids. It is found that phantom energy accretes onto black holes for u < 0. Further, the location of critical point of accretion are evaluated that leads to mass to charge ratio for 5D charged black hole. This ratio implies that accretion cannot transform a black hole into a naked singularity. We would like to mention here that this work is an irreducible extension of 4D charged black hole.

A new method based on Synge's world function is developed for determining within the WKB approximation the gravitationally induced quantum phase shift of a particle propagating in a stationary spacetime. This method avoids any calculation of geodesics. A detailed treatment is given for relativistic particles within the weak field, linear approximation of any metric theory. The method is applied to the calculation of the oscillation terms governing the interference of neutrinos considered as the superposition of two eigenstates having different masses. It is shown that the neutrino oscillations are not sensitive to the gravitomagnetic components of the metric as long as the spin contributions can be ignored. Explicit calculations are performed when the source of the field is a spherical, homogeneous body. A comparison is made with previous results obtained in Schwarzschild spacetime.

Phase shifts produced by two supersymmetric partner potentials satisfy a simple relation. One expects that the phase shift can be obtained algebraically, if the potential is shape invariant. We show that this is true only for a special class of shape invariant potentials. Among known shape invariant potentials, only the Coulomb potential satisfy this requirement. The Coulomb phase shift can be obtained analytically, which agrees with the well-known standard result.