arXiv subjects

Moshe M. Chaichian

Publications and source records attributed to Moshe M. Chaichian.

7 recordsLinked to original sources

arXiv2026

Rotation of the polarization plane in axion fields: application to neutron star polar cap regions

We study observable manifestations of an axion field, focusing on possible polarizational effects for electromagnetic wave propagating in such a special magnetoelectric medium. The corresponding analysis is based on a geometric model of the Casimir type, in the framework of which the rotation angle of the polarization plane is derived to the lowest order. The results obtained are discussed for astrophysical conditions of a neutron star, where an existence of a locally inhomogeneous axion region is predicted in the polar cap.

hep-ph↗

arXiv2026

Renormalizable and unitary nonlocal quantum field theory with CPT violation and its implication

It is a common belief that any relativistic nonlocal quantum field theory encounters either the problem of renormalizability or unitarity or both of them. It is also known that any local relativistic quantum field theory (QFT) possesses the CPT symmetry. In this Letter we show that a previously proposed nonlocal Lorentz invariant QFT, which violates the CPT theorem, is both renormalizable and unitary, thus being a first presented example in the literature of such a nonlocal theory. The theory satisfies the requirement of causality as well. A further generalization of such a nonlocal QFT to include the gauge theories is also envisaged. In particular, dressing such a Standard Model with a CP violating phase, will make the theory satisfying most of the necessary criteria to finally explain the baryon asymmetry of the universe by a viable QFT. As for the necessity of baryon number violation, there are hopefully several possibilities such as by GUT and electroweak baryogenesis, leptogenesis or sphalerons.

hep-th↗

arXiv2026

Comment on the "Electric Power Generation from Earth's Rotation through its Own Magnetic Field"

The suggestion made by C. F. Chyba and K. P. Hand about electric power generation from Earth's rotation through its own magnetic field is intriguing [1, 2]. Due to the importance of the subject, we have re-analyzed the theoretical arguments and derivations leading to their conclusion, by paying special attention to several issues possibly neglected before. The model they consider is a magnetic cylindrical shell moving with velocity $\mathbf{v}$ in the $y$ direction at a right angle to the direction of the Earth's magnetic field $\mathbf{B}_\infty$. First we analyze the electromagnetic boundary conditions when the shell is moving with a constant velocity $\mathbf{v}$, as this point, although of importance, has not been taken care of in [1, 2]. Indeed, this procedure leads us to differences in the values of electromagnetic fields when compared with the expressions given in the cited references. Second and as a result, we find that the mechanical force created by the moving shell becomes different from the one derived in [1, 2]. Obviously, the expression for the amount of electric power generation from Earth's rotation will also be different from the previously obtained one. The latter is important for evaluating the amount of produced power, maximizing it by choosing the parameters of the shell, and for the comparison with experimental findings.

physics.class-ph↗

arXiv2025

Below the Schwinger critical magnetic field value, quantum vacuum and gamma-ray bursts delay

A magnetic field above the Schwinger critical value $B_{\rm crit} = 10^9$ Tesla is much higher than any magnetic field known by now in the interstellar bulk except in the vicinity of observed magnetars with magnetic fields between $10^9$ and $10^{11}~$Tesla. Above the critical magnetic field, calculated by Schwinger in the lowest order perturbation in quantum electrodynamics (QED), one reaches the threshold for electron-positron pair creation, which has interesting consequences. Therefore, finding out whether one could encounter some consequences of interest also for the values of the magnetic field below the Schwinger critical point, we invoke the next higher-order effect in QED, which is emerging from the Quantum Vacuum Effect. The latter is equivalent to the use of the Euler-Heisenberg effective theory in nonlinear electrodynamics, where the Lagrangian has a term with a higher power, $B^4$. In this case, in the region $B<B_{\rm crit}$, we show that interesting effects appear, among them the Cherenkov radiation and the reduction in the speed of light. The latter effects appear because of the quantum vacuum mimicking a medium. We also present quantitative arguments for such a close analogy. As a rough estimate, we show that the time delay $τ$ of gamma-ray bursts (GRB) having traveled through the entire cosmological distances in an average strong magnetic field such as $10^6~$Tesla, reaches an experimentally considerable value of $τ= 2.4$ hours. In the vicinity of magnetars, the magnetic field is much stronger, of the order of $10^9-10^{11}$ Tesla. However, in this case the linear scale of GRB trajectory through such regions would be much smaller. For the latter, we give an estimate for the number of the magnetars along the trajectory and also for the delay. Finally, we shall dwell on the recently raised issue in the literature, namely the Lorentz invariance violation (LIV).

hep-ph↗

arXiv2024

Galaxy groups in the presence of Cosmological Constant: Increasing the Masses of Groups

The boundaries of galaxy groups and clusters are defined by the interplay between the Newtonian attractive force and the decoupling from the local expansion of the Universe. This work extends the definition of a zero radial acceleration surface (ZRAS) and the turnaround surface (TS) for a general distribution of the masses in an expanding background, governed by the cosmological constant. We apply these definitions to different galaxy groups in the local Universe, mapping these groups up to ten megaparsec distances. We discuss the dipole and the quadrupole rate for the Local Group of Galaxies and the implementations on the Hubble diagram correction and galaxy groups virialization. With these definitions, we present the surfaces showing the interplay between the local expansion vs the local Newtonian attraction for galaxy groups in the local Universe. Further, we estimate the masses of different galaxy groups and show that the inclusion of the Cosmological Constant in the analysis predicts these masses to be higher by 5-10\%. For instance the Local Group of Galaxies is estimated to be $(2.47 \pm 0.08) \cdot 10^{12} M_{\odot}$. For the groups with enough tracers close to the TS, the contribution of the Cosmological Constant makes the masses to be even higher. The results show the importance of including the local cosmic expansion in analyzing the Cosmic Flow of the local Universe.

astro-ph.GA↗

arXiv2024

Reciprocal of the CPT theorem

The CPT theorem originally proven by Lüders and Pauli ensures the equality of masses, lifetimes, magnetic moments and cross sections of any particle and its antiparticle. We show that in a Lorentz invariant quantum field theory described by its Lagrangian, CPT-violating interaction alone does not split the masses of an elementary particle and its antiparticle but breaks only the equality of lifetimes, magnetic moments and cross sections. However, CPT violation in the mass term of a field in the Lagrangian, which can be attributed to be due to the size of the particle described by a form factor, breaks only the equality of masses. Also it is shown that the two separate effects of CPT violation in the interaction terms or in the mass term do not mix due to higher quantum corrections and remain distinguishable. Thus, we urge the experimentalists to search for such observable effects concerning differences in the masses, magnetic moments, lifetimes and cross sections between the elementary or bound state particles and their antiparticles. In the case of CPT violation only in the mass term, besides the difference in the masses of elementary bound state particles and their antiparticles, there will be also an extremely tiny difference in the lifetimes of bound states due to the difference in their phase spaces. From the details of calculations, it appears that the separate effects of the CPT violation described above are quite general, neither depending on how the nonlocality is achieved, nor depending on what this violation is due to: due to T violation, as considered in the present work, which can be attributed to a cosmological direction of time; to CP or to both T and CP violations. The latter two cases satisfy the Sakharov's conditions for explaining the baryon asymmetry in the Universe.

hep-th↗

arXiv2022

Axion electrodynamics: Energy-momentum tensor, and possibilities for experimental tests

Axion electrodynamics is based upon the Lagrangian of the electromagnetic (EM) field plus its interaction with the axions, and is accordingly a physically open system. It means that the four-divergence of the EM energy-momentum tensor is different from zero, implying in turn that the total EM energy and momentum (when integrated over all space) do not constitute a four-vector. The EM force is in principle accessible to experimental detection, just analogous to what is the case in ordinary electrodynamics. In the first half of this paper the energy-momentum aspects of axion electrodynamics are worked out in general, when the surroundings are allowed to be a medium with constant permittivity and permeability. In the second half, two examples are discussed. The first is a static situation, where a block of uniform material containing axions is exposed to external strong electric and magnetic fields. Assuming the axion amplitude $a(x)$ (i.e. its density) to increase linearly in one direction, we calculate the axion-generated forces. As a second example, we consider axions varying not with position but instead harmonically with time; this is the constellation usually assumed in astrophysics. Assuming a Gaussian profile for the EM wave emitted from the Earth towards an axion cloud in outer space, we make a calculation of the 'axion echo', the return signal.

hep-ph↗