arXiv subjects

Kamran Kaviani

Publications and source records attributed to Kamran Kaviani.

5 recordsLinked to original sources

arXiv2017

Multiverse effects on the CMB angular correlation function in the framework of NCG

Following many theories that predict the existence of the multiverse and by conjecture that our space-time may have a generalized geometrical structure at the fundamental level, we are interested in using a non-commutative geometry (NCG) formalism to study a suggested two-layer space that contains our 4-dimensional (4-D) universe and a re-derived photon propagator. It can be shown that the photon propagator and a cosmic microwave background (CMB) angular correlation function are comparable, and if there exists such a multiverse system, the distance between the two layers can be estimated to be within the observable universe's radius. Furthermore, this study revealed that our results are not limited to CMB but can be applied to many other types of radiation, such as X-rays.

hep-th↗

arXiv2013

From Dimensional Reduction of 4d Spin Foam Model to Adding Non-Gravitational Fields to 3d Spin Foam Model

A Kaluza-Klein like approach for a 4d spin foam model is considered. By applying this approach to a model based on group field theory in 4d (TOCY model), and using the Peter-Weyl expansion of the gravitational field, reconstruction of new non gravitational fields and interactions in the action are found. The perturbative expansion of the partition function produces graphs colored with su(2) algebraic data, from which one can reconstruct a 3d simplicial complex representing space-time and its geometry; (like in the Ponzano-Regge formulation of pure 3d quantum gravity), as well as the Feynman graph for typical matter fields. Thus a mechanism for generation of matter and construction of new dimensions are found from pure gravity.

gr-qc↗

arXiv2006

New Computational Approaches to Analysis of Interbeat Intervals in Human Subjects

We investigate the Markov nature, Cascade of information from large time scale to small scale and extended self similarity properties of the beat to beat fluctuations of healthy subjects as well as those with congestive heart failure. To check the Markov nature, we use a novel inverse method that utilizes a set of data to construct a simple equation that governs the stochastic process for which the data have been measured, hence enabling us to reconstruct the stochastic process. The inverse method provides a novel technique for distinguishing the two classes of subjects in terms of a drift and a diffusion coefficients which behave completely differently for the two classes of subjects.To investigate the cascade of information from large to small time scales we also analyze the statistical properties of interbeat intervals cascade by considering the joint probability distribution for two interbeat increments. As a result, the joint probability distributions of the increments in the interbeat intervals obey a Fokker-Planck equation. Finally we analyze the extended self-similarity (ESS) in the beat-to-beat fluctuations in the heart rates of healthy and congestive heart failure subjects.The proposed methods provide the novel techniques for distinguishing the two classes of subjects in terms of the drift and diffusion coefficients, intermittency exponents which behave differently for two classes of the subjects, namely, healthy subjects and those with congestive heart failure.

q-bio.QM↗

arXiv1998

Riemannian geometry of the Pauli paramagnetic gas

We investigate the thermodynamic curvature resulting from a Riemannian geometry approach to thermodynamics for the Pauli paramagnetic gas which is a system of identical fermions each with spin 1/2. We observe that the absolute value of thermodynamic curvature can be interpreted as a measure of the stability of the considered system only in the classical and semiclassical regime. But in quantum regime some exceptions are observed.

cond-mat.stat-mech↗

arXiv1997

M-Branes and Their Interactions in Static Matrix Model

Different BPS M-brane configurations including single and two parallel M$p$-branes ($p$= even) and M5-branes are introduced as the classical solutions of the recently proposed Static Matrix Model. Also the long range interactions of two relatively rotated M$p$-branes (one and two angles) and M$p$-brane--anti-M$p$-brane are calculated. The results are in agreement with 11 dimensional supergravity results.

hep-th↗