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A. H. Fatollahi

Publications and source records attributed to A. H. Fatollahi.

13 recordsLinked to original sources
arXiv2023

Gauge theory on a space with linear Lie type fuzziness

The U(1) gauge theory on a space with Lie type noncommutativity is constructed. The construction is based on the group of translation in Fourier space, which in contrast to space itself is commutative. In analogy with lattice gauge theory, the object playing the role of flux of field strength per plaquette, as well as the action, are constructed. It is observed that the theory, in comparison with ordinary U(1) gauge theory, has an extra gauge field component. This phenomena is reminiscent of similar ones in formulation of SU(N) gauge theory in space with canonical noncommutativity, and also appearance of gauge field component in discrete direction of Connes' construction of the Standard Model.

hep-th↗
arXiv2022

Relativistic frequency shifts in a rotating waveguide

A photon source is located in a rotating waveguide. An absorber with a sharp absorbing frequency absorbs some of the emitted photons. This decreases the number of photons which are detected by a detector. The frequency (energy) spectrum measured in the absorber depends on the setup (the positions of the source and the detector), and this spectrum determines the amount of absorption. The shifts are calculated for different configurations. Among other things, it is seen that even if the source and the absorber are at rest (while the waveguide is rotating), there is a nonzero frequency shift.

physics.class-ph↗
arXiv2018

Electric Charge in Presence of Fixed Monopole-Antimonopole Pair

The dynamics of an electric charge $e$ in presence of a fixed monopole pair $\pm g$ is considered. Depending on the ratio of the angular momentum to $e\,g/c$, the effective potential may consist a minimum valley between the poles or a finite depth well. In the classical limit the charge may be bound to the poles inside the minimum valley or well. In the quantum theory, due to the finite barrier between the minimum and the potential at infinity, only approximate or quasi bound-states are possible. Based on the Rayleigh-Ritz variational method the energy and eigen-functions are obtained. The implications on the proposed confining mechanism based on the dual picture of the so-called Meissner effect is pointed.

physics.gen-ph↗
arXiv2012

Dirac theory on a space with linear Lie type fuzziness

A spinor theory on a space with linear Lie type noncommutativity among spatial coordinates is presented. The model is based on the Fourier space corresponding to spatial coordinates, as this Fourier space is commutative. When the group is compact, the real space exhibits lattice characteristics (as the eigenvalues of space operators are discrete), and the similarity of such a \emph{lattice} with ordinary lattices is manifested, among other things, in a phenomenon resembling the famous \emph{fermion doubling} problem. A projection is introduced to make the dynamical number of spinors equal to that corresponding to the ordinary space. The actions for free and interacting spinors (with Fermi-like interactions) are presented. The Feynman rules are extracted and 1-loop corrections are investigated.

hep-th↗
arXiv2008

Loop diagrams in space with SU(2) fuzziness

The structure of loop corrections is examined in a scalar field theory on a three dimensional space whose spatial coordinates are noncommutative and satisfy SU(2) Lie algebra. In particular, the 2- and 4-point functions in $ϕ^4$ scalar theory are calculated at the 1-loop order. The theory is UV-finite as the momentum space is compact. It is shown that the non-planar corrections are proportional to a one dimensional $δ$-function, rather than a three dimensional one, so that in transition rates only the planar corrections contribute.

hep-th↗
arXiv2007

Field theory amplitudes in a space with SU(2) fuzziness

The structure of transition amplitudes in field theory in a three-dimensional space whose spatial coordinates are noncommutative and satisfy the SU(2) Lie algebra commutation relations is examined. In particular, the basic notions for constructing the observables of the theory as well as subtleties related to the proper treatment of $δ$ distributions (corresponding to conservation laws) are introduced. Explicit examples are given for scalar field theory amplitudes in the lowest order of perturbation.

hep-th↗
arXiv2007

Field theories on spaces with linear fuzziness

A noncommutative space is considered the position operators of which satisfy the commutativity relations of a Lie algebra. The basic tools for calculation on this space, including the product of the fields, inner product and the proper measure for integration are derived. Some general aspects of perturbative field theory calculations on this space are also discussed. Among the features of such models is that they are free from ultraviolet divergences (and hence free from UV/IR mixing as well), if the group is compact. The example of the group SO(3) or SU(2) is investigated in more detail.

hep-th↗
arXiv2006

Black-Body Radiation Of Noncommutative Gauge Fields

The black-body radiation is considered in a theory with noncommutative electromagnetic fields; that is noncommutativity is introduced in field space, rather than in real space. A direct implication of the result on Cosmic Microwave Background map is argued.

hep-th↗
arXiv2000

Multispecies reaction-diffusion systems

Multispecies reaction-diffusion systems, for which the time evolution equation of correlation functions become a closed set, are considered. A formal solution for the average densities is found. Some special interactions and the exact time dependence of the average densities in these cases are also studied. For the general case, the large time behaviour of the average densities has also been obtained.

cond-mat↗
arXiv1998

Regularised Supermembrane Theory and Static Configurations of M-Theory

We suggest that the static configurations of M-theory may be described by the matrix regularisation of the supermembrane theory in static regime. We compute the long range interaction between a M2-brane and an anti-M2-brane in agreement with the 11 dimensional supergravity result.

hep-th↗
arXiv1998

Interaction of Branes at Angles in M(atrix) Model

Interactions of relatively rotated Dp-branes in 1, 2, 3 and 4 angles in M(atrix) model are calculated and it is found to be in agreement with string theory calculations. In 4 angles case the agreement is achieved after subtracting the contribution of the single chiral fermionic zero mode.

hep-th↗
arXiv1996

Non-Commutative Geometry and Chiral Perturbation Lagrangian

Chiral perturbation lagrangian in the framework of non-commutative geometry is considered in full detail. It is found that the explicit symmetry breaking terms appear and some relations between the coupling constants of the theory come out naturally. The WZW term also turns up on the same footing as the other terms of the chiral lagrangian.

hep-th↗