arXiv subjects

Maysam Yousefian

Publications and source records attributed to Maysam Yousefian.

5 recordsLinked to original sources

arXiv2025

Metric Field as Emergence of Hilbert Space

First, we explain some ambiguities of spacetime and metric field as fundamental concepts. Then, from the Unruh effect point of view and using the Gelfand-Naimark-Segal construction, we construct an operator as a quanta of acceleration that we call quantum acceleration operator (QAO). Thereupon, we investigate the relation between the vacuum of two different frames in the Minkowski space. Also, we show that the vacuum of each accelerated frame in the Minkowski space can be obtained by applying such a QAO to the Minkowski vacuum. Furthermore, utilizing these QAOs, we augment the Hilbert space and then extract the metric field of a general frame of the Minkowski spacetime. In this approach, these concepts emerge from the Hilbert space through the constructed QAOs. Accordingly, such an augmented Hilbert space includes quantum field theory in a general frame and can be considered as a fundamental concept instead of the classical metric field and the standard Hilbert space.

gr-qc↗

arXiv2021

A `Third' Quantization Constructed for Gauge Theory of Gravity

In general, a global and unique vacuum state cannot be constructed for a curved space. As a remedy, we introduce a curved space background geometry with a Minkowski metric tensor and locally non-zero curvature and torsion. Based on this geometry, we propose a `third'/vacuum quantization model as a consequence of Unruh effect. Accordingly, we introduce a `third' quantization scalar field as a general coordinate transformation of spacetime for the second quantization fields. Then we show that in the classical limit, the `third' quantization fields appear as Riemannian manifolds with an emergent metric on which the second quantization fields are located. This way, the standard model of field theory turns out as an effective theory. Moreover, using the proposed `third' quantization fields, we build a $U(1)\times SU(4)$ Yang-Mills gauge theory for gravity. According to this gravitational model, we indicate that an analytical solution of the presented gravitational model, for the `third' quantum field particle trajectory (such as a star), corresponds to the trajectory of a test particle in the Mannheim-Kazanas space. Furthermore, by using non-perturbative methods and lattice gauge theory results, we render a solution for the potential of the constructed model that can explain the galaxy rotation curves and gravitational lensing without any need to dark matter. We also address the cosmic microwave background phenomenon and the expansion of the universe.

hep-th↗

arXiv2021

Towards Amplituhedron via One-Dimensional Theory

Inspired by the closed contour of momentum conservation in an interaction, we introduce an integrable one-dimensional theory that underlies some integrable models such as the Kadomtsev-Petviashvili (KP)-hierarchy and the amplituhedron. In this regard, by defining the action and partition function of the presented theory, while introducing a perturbation, we obtain its scattering matrix (S-matrix) with Grassmannian structure. This Grassmannian corresponds to a chord diagram, which specifies the closed contour of the one-dimensional theory. Then, we extract a solution of the KP-hierarchy using the S-matrix of theory. Furthermore, we indicate that the volume of phase-space of the one-dimensional manifold of the theory is equal to a corresponding Grassmannian integral. Actually, without any use of supersymmetry, we obtain a sort of general structure in comparison with the conventional Grassmannian integral and the resulted amplituhedron that is closely related to the Yang-Mills scattering amplitudes in four dimensions. The proposed theory is capable to express both the tree- and loop-levels amplituhedron (without employing hidden particles) and scattering amplitude in four dimensions in the twistor space as particular cases.

hep-th↗

arXiv2021

QED Treatment of Linear Elastic Waves in Asymmetric Environments

Considering the importance of correctly understanding the dynamics of microstructure materials for their applications in related technologies, by eliminating the shortcomings and some overlooked physical concepts in the existing asymmetric elastic theories, we have presented an asymmetric elastodynamic model based on a U(1) gauge theory with quantum electrodynamics (QED) structure. Accordingly, we have shown that there is a correspondence between an elastic theory, which can explain the behavior of elastic waves within an asymmetric elastic medium, and QED. More specific, we have indicated that the corresponding elastic wave equations are somehow analogous to QED ones. In this regard, by adding vibrational degrees of freedom and introducing a gauge property of the waves of displacement for the waves of rotation, we have generalized and modified the related Cosserat theory (CT) for an elastic environment. Thus on macro scales, the elastic waves can possess the QED treatment. This analogy provides a new paradigm of fermions and bosons. Also, from experimental point of view, we have shown that the behavior of elastic waves in a granular medium is equivalent to behavior of light in dispersive media, which can be explained using QED. Hence, contrary to the Cosserat and discrete models, this amended CT has qualitatively been indicated to be consistent with the corresponding empirical observations.

physics.class-ph↗

arXiv2015

Ether and Relativity

We consider one of the fundamental debates in performing the relativity theory, namely, the ether and the relativity points of view, in a way to aid the learning of the subjects. In addition, we present our views and prospects while describing the issues that being accessible to many physicists and allowing broader views. Also, we very briefly review the two almost recent observations of the Webb redshift and the ultra high-energy cosmic rays, and the modified relativity models that have been presented to justify them, wherein we express that these justifications have not been performed via a single model with a single mechanism.

gr-qc↗