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S C Tiwari

Publications and source records attributed to S C Tiwari.

At least 19 recordsLinked to original sources
arXiv2026

Comment on "Quantum mechanics based on real numbers: a consistent description"

In this comment on arXiv:2503.17307 (PRL, 136, 240202, 2026), a novel idea using flag states to transform complex state vector and operators to real ones is argued to effectively lead to a quantum mechanics that is complex in the disguised form of real. The claim that real-valued quantum mechanics cannot be falsified is conceptually flawed. A new criterion based on the geometric phases is suggested to compare real and complex versions of quantum mechanics.

physics.gen-ph↗
arXiv2025

Harmonic Spinors and $Z_2$ Vortex

Hodge theorem and harmonic spinors are studied in a physics-oriented approach in the present paper. New mathematical results on the harmonic spinors are as follows. Harmonic spinors defined by partial differential operators could be of two types: trivial without topological defects, and having nontrivial topological structures, for example, phase singularities or phase vortices. There could exist a nontrivial harmonic vector field associated with nontrivial harmonic spinor, for example, ${\bf v}_{vortex}$ associated with Weyl 2-spinor. The $Z_2$-vortex is re-visited in the perspective of harmonic spinors leading to a remarkable result that the gauge potential is exactly the same as the nontrivial harmonic vector field associated with the 2-spinor. It is proposed that a discrete symmetry group $SL(2, Z)$ has a role in connection with the continuous group $SU(2)$ similar to the discrete group $Z_2$ in $U(1)$.

physics.gen-ph↗
arXiv2024

A note on diffeomorphism-invariance in gravitational field equations

The notion of diffeomorphism invariance and general covariance are conceptually delicate issues for the field equations and the actions. A thorough study on the original Einstein field equation and its two modifications by Einstein is presented. It is concluded that the cosmological constant and the unimodular condition are independent concepts, and the unimodular condition has no direct role in the derivation of the traceless field equation. Unimodular gravity with unambiguous action does not exist, and the derivation of traceless equation from the action principle is an open question.

physics.gen-ph↗
arXiv2024

Physical mechanism for the geometric phases in optics and angular momentum holonomy

Vast literature on the experiments and mathematical formulations on the geometric phases signifies the importance of this subject. Physical mechanism for the origin of the geometric phases in optics was suggested in 1992 by the author in terms of the exchange of the angular momentum. Some of the literature has taken notice of it, however, the real import of the suggested mechanism and the angular momentum holonomy conjecture has remained elusive. The present contribution delineates the prevailing confusions and offers a thorough discussion on the nature of the light waves to resolve the conceptual issues. It is argued that at a fundamental level there exist only two types of geometric phases arising from (i) the geometry of the wave vector space, and (ii) the polarization state space. For the light beams of definite polarization spatial modes (HG or LG modes) the geometric phase has origin in the wave vector space that is different than the spin redirection phase for the polarized light. Angular momentum holonomy is proposed to be equivalent to the geometric phase in general.

physics.gen-ph↗
arXiv2023

Topological photon, spin, and Euclidean group E(2)

The proposition that photon is a topological object (J. Math. Phys. 49, 032303, 2008) is given rigorous foundation based on pure vector field theory independent of the electromagnetic fields. Holomorphy of 4-dimensional space-time and the nature of topological obstructions are investigated to articulate singular vortex model for photon. The utility of the Euclidean symmetry group is discussed in detail for the proposed photon model.

physics.gen-ph↗
arXiv2023

Symmetry of Dirac two-oscillator system, gauge-invariance, and Landau problem

Role of gauge symmetry in the proton spin problem has intricate and unresolved aspects. One of the interesting approaches to gain physical insights is to explore tha Landau problem in this context. A detailed study using the group theoretic method to understand the Landau problem establishes the significance of the gauge transformation intimately related with the space translation symmetry. An important implication of this result is that the E(2)-like Wigner's little group for massless particles could throw more light on the question of gauge symmetry in QED and QCD. A generalized Landau-Zeeman Hamiltonian is proposed in which Dirac two-oscillator system and the symmetry of the group SO(3,2) become important. It is argued that nontrivial topology of pure gauge field holds promise to resolve the unsettled questions.

physics.gen-ph↗
arXiv2023

Dirac representation of the group SO(3,2) and the Landau problem

A systematic study carried out on the infinite degeneracy and the constants of motion in the Landau problem establishes the central extension of the Euclidean group in two dimension as a dynamical symmetry group, and Sp(2,R) as spectrum generating group irrespective of the choice of the gauge. It may be noted that the siginificance of the Euclidean group was already implicit in the earlier works on the Landau problem; in the present paper the method of group contraction plays an important role. Dirac's remarkable representation of the group SO(3,2) and the isomorphism of this group with Sp(4,R) are re-visited. New insights are gained on the meaning of two-oscillator system in Dirac representation. It is argued that in view of the fact that even the two dimensional isotropic oscillator having SU(2) as dynamical symmetry group does not arise in the Landau problem the relevance or applicability of SO(3,2) group becomes invalid.

physics.gen-ph↗
arXiv2020

Anomalous magnetic moment and vortex structure of the electron

The electron magnetic moment decomposition calculated in QED is proposed to have origin in a multi-vortex internal structure of the electron. This proposition is founded on two important contributions of the present work. First, a critical review on Weyl model of electron, Einstein-Rosen bridge and Wheeler's wormholes leads to a new idea of a topological defect in cylindrical space-time geometry as a natural representation of the electron. A concrete realization of this idea in terms of the derivation of a new vortex-metric, and its physical interpretation to establish the geometric origin of the electron magnetic moment decomposition constitute the second contribution. Remarkable occurrence of a vortex structure in the basis mode function used in BLFQ is also pointed out indicating wider ramification of the proposed electron model.

physics.gen-ph↗
arXiv2019

Real wave equations, spin origin of charge, and outlook on particle physics

Radical revision on the conventional spacetime picture, illusion or emergent phenomenon, has been the focus of the speculations on the unified frameworks for fundamental interactions in nature. Compared to strong experimental credence to the standard model of particle physics there is practically no relation of these speculations with the world of real particles. In this paper we present a new conceptual framework for particle physics in which nontrivial geometry and topology of space and time have fundamental reality. To develop this model we proceed with the analysis of the standard wave equations and make them real using the transformation rule $i=\sqrt{-1} \rightarrow C=\begin{bmatrix} 0 & 1 \\ -1 & 0 \end{bmatrix}$. Topological significance is attached to $i$ in terms of a point defect in 1D directed line. New interpretation of Schroedinger wave equation and $Z_2$ vortex throw light on the nature of spin. A new meaning is also obtained on U(1) gauge symmetry and charge. Novel properties of C-matrix and known applications are presented. Topological origin of spin is inferred from the interpretation of Pauli algebra that they signify 2D directed area in phase space as topological obstruction. Electron magnetic moment decomposition in QED serves the basis for the proposition: spin origin of charge (SOC). A dynamical logarithmic spiral geometric structure comprising of 2+1D braids, 3 vortices with associated three 2-spinors is envisaged based on SOC. It is termed as meta-electron; meta-neutrino has 2-vortex structure. These are the only building blocks of all particles having the knotted vortex structures in our model. Coupling strengths of the three fundamental interactions are related with the magnitudes of the spin angular momentum of constituent spinors of the meta-electron.

physics.gen-ph↗
arXiv2019

Stochasticity, topology, and spin

Complex Schroedinger equation is transformed to spinor or coupled scalar field equations replacing the imaginary unit $i$ by a matrix $\begin{bmatrix} 0 & 1 \\-1 & 0 \end{bmatrix}$. New perspecive on stochasic approach is developed with spin as topological invariant and mass having stochastic origin in this Spinor Random Field formalism.

physics.gen-ph↗
arXiv2019

Unified field theories and Einstein

Einstein's contribution to relativity is reviewed. It is pointed out that Weyl gave first unified theory of gravitation and electromagnetism and it was different than the five dimensional theory of Kaluza. Einstein began his work on unification in 1925 that continued all through the rest of his life. A discussion is presented on the recent advances in Weyl theory, and also on the unification approach in which space-time is believed not to be fundamental. The significance of the gravitational waves observed recently seems to indicate a new paradigm of unification. It is suggested that the nature of time is the most fundamental issue for a break-through in the unification quest.

physics.gen-ph↗
arXiv2018

Magnon-phonon conversion experiment and phonon spin

Recent experiment demonstrates magnon to phonon conversion in a YIG film under the application of a non-uniform magnetic field. Light scattered from phonons is observed to change its polarization state interpreted by the authors signifying phonon spin. In this note we argue that the experimental data merely shows the exchange of angular momentum $\pm \hbar$ per photon. We suggest that it has physical origin in the orbital angular momentum of phonons. The distinction between spin and orbital parts of the total angular momentum, and between phonons and photons with added emphasis on their polarizations is explained. The main conclusion of the present note is that phonon spin hypothesis is unphysical.

physics.gen-ph↗
arXiv2017

Do phonons carry spin?

Recently the question of phonon angular momentum has been raised : phonon angular momentum in a magnetic crystal could play an important role in the angular momentum balance in the Einstein-de Haas effect. This proposition is quite natural and understandable, however the idea of phonon spin seems ambiguous in the literature. In 1988 McLellan presented phonon angular momentum states for circular and elliptical polarizations of phonons that represent orbital angular momentum and also pointed out analogy to isotropic quantum harmonic oscillator. In view of its fundamental importance we investigate this issue and conclude that phonon spin hypothesis is physically untenable, and the phonon angular momentum has to be interpreted as orbital. The photon-phonon analogy is also misleading. It is argued that Cosserat elastic medium having internal torque may have lattice excitations different from phonons having spin one or spin two that we term as Cosseratons. In addition a new source of angular momentum balance originationg from anomalous electron magnetic moment is suggested.

physics.gen-ph↗
arXiv2017

Spintronics: Maxwell-Dirac theory, charge and spin

The nature of spin current and the separation of charge current and spin current are two of the fundamental questions in spintronics. For this purpose the classical limit of the Maxwell-Dirac theory is investigated in the present contribution. Since the Dirac equation reduces to the Weyl equation for massless particles, a vortex solution is obtained for the Weyl equation and it is argued that mass has stochastic origin. The Weyl vortex is embedded in a Gaussian wavepacket to define physical vortex. Two-vortex internal structure of electron is developed in terms of Weyl and sub-quantum Weyl vortices characterized by $\hbar$ and $f=e^2/2πc$ respectively. It is suggested that this model may find application in spintronics with a new perspective.

physics.gen-ph↗
arXiv2017

Comment on 'Relativistic electron wavepackets carrying angular momentum'

This is a comment on arXiv:1611.04445 (PRL, 118, 114801 (2017)). It is pointed out that the fundamental problems in light beam vortices and the relativistic electron vortices are not identical and have subtle differences. The significance of two length scales is underlined for the electron vortices. Local gauge transformation on the Gordon current admits vortex structure.

physics.gen-ph↗
arXiv2016

Proton spin: a topological invariant

Proton spin problem is given a new perspective with the proposition that spin is a topological invariant represented by a de Rham 3-period. The idea is developed generalizing Finkelstein-Rubinstein theory for Skyrmions/kinks to topological defects, and using nonabelian de Rham theorems. Two kinds of de Rham theorems are discussed applicable to matrix valued differential forms, and traces. Physical and mathematical interpretations of de Rham periods are presented. It is suggested that Wilson lines and loop operators probe the local properties of the topology, and spin as a topological invariant in pDIS measurements could appear with any value from 0 to $\frac{\hbar}{2}$, i. e. proton spin decomposition has no meaning in this approach.

physics.gen-ph↗
arXiv2016

Comment on 'Attempts to test an alternative electrodynamic theory of superconductors by low-temperature scanning tunneling and atomic force microscopy'

It is argued that alternative electrodynamics of superconductivity proposed by Hirsch lacks mathematical rigour and it is conceptually flawed. Gauge non-invariance of the theory makes justification of the experiment reported in [arXiv:1607.05060] to test its prediction doubtful. It seems even with improved techniques the outcome would remain inconclusive.

physics.gen-ph↗