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D. V. Ahluwalia

Publications and source records attributed to D. V. Ahluwalia.

At least 55 records · Page 3Linked to original sources
arXiv1999

Nonlocality and gravity-induced CP violation

We consider a space-time dependent relative phase between the right- and left-handed spinors and show that it results in a violation of locality in the presence of gravity once the demand of parity covariance is dropped. This violation of locality is such that it readily interprets itself as a gravity-induced CP violation, and at the same time confirms an earlier remark by Wigner that a representation space carries more information than a wave equation. This happens, as Kirchbach has noted, because while the dimensionality of an irreducible representation space does not depend upon the concrete realization of the symmetry generators, Noether currents (Dirac, versus Majorana, versus the CP violating construct presented here) do. The gravity-induced CP violation provides a dynamical reason on how a neutron star carrying its baryon and lepton numbers can collapse into a black hole and loose information on the latter characteristics.

hep-ph↗
arXiv1998

Reconciling Super-Kamiokande, LSND, and Homestake neutrino-oscillation data

The L/E-flatness of the e-like events observed in the recent atmospheric-neutrino data from Super-Kamiokande (SuperK) is interpreted to reflect a new symmetry of the neutrino-oscillation mixing matrix. From that we obtain an analytical set of constraints yielding a class of mixing matrices of the property to simultaneously fit both the SuperK and the LSND data. The resulting mass squared difference relevant for the LSND experiment is found as 0.3 eV^2. The discussed symmetry, e.g., carries the nature that expectation values of masses for ν_μand ν_τare identical. These considerations are purely data dictated. A different framework is then applied to the solar neutrino problem. It is argued that a single sterile neutrino is an unlikely candidate to accommodate the data from the four solar neutrino experiments. A scenario is discussed which violates CPT symmetry, and favors the ν_e - \barν_e system to belong to the `self'-`anti-self' charge conjugate construct in the (1/2,0)+(0,1/2) representation space, where the needed helicity flipping amplitudes are preferred, rather than the usual Dirac, or Majorana, constructs. In the presented framework the emerging SuperK data on solar neutrino flux is reconciled with the Homestake, GALLEX, and SAGE experiments. This happens because the former detects not only the solar ν_e but also, at a lower cross section, the oscillated solar \barν_e; while the latter are sensitive only to the oscillation-diminished solar ν_e flux. A direct observation of solar \barν_e by SNO will confirm our scenario. Finally, we consider the possibility for flavor-dependent gravitational couplings of neutrinos as emerging out of the noncommutativity of the quantum operators associated with the measurements of energy and flavor.

hep-ph↗
arXiv1998

Can general-relativistic description of gravitation be considered complete?

The local galactic cluster, the Great attractor, embeds us in a dimensionless gravitational potential of about - 3 x 10^{-5}. In the solar system this potential is constant to about 1 part in 10^{11}. Consequently, planetary orbits, which are determined by the gradient in the gravitational potential, remain unaffected. However, this is not so for the recently introduced flavor-oscillation clocks where the new redshift-inducing phases depend on the gravitational potential itself. On these grounds, and by studying the invariance properties of the gravitational phenomenon in the weak fields, we argue that there exists an element of incompleteness in the general-relativistic description of gravitation. An incompleteness-establishing inequality is derived and an experiment is outlined to test the thesis presented.

gr-qc↗
arXiv1998

Interplay of gravitation and linear superposition of different mass eigenstates

The interplay of gravitation and the quantum-mechanical principle of linear superposition induces a new set of neutrino oscillation phases. These ensure that the flavor-oscillation clocks, inherent in the phenomenon of neutrino oscillations, redshift precisely as required by Einstein's theory of gravitation. The physical observability of these phases in the context of the solar neutrino anomaly, type-II supernovae, and certain atomic systems is briefly discussed.

gr-qc↗
arXiv1997

Three Quantum Aspects of Gravity

It is argued that (a) In the quantum realm test-particle masses have non-trivial observability which induces a non-geometric element in gravity, (b) Any theory of quantum gravity, on fundamental grounds, must contain an element of non-locality that makes position measurements non-commutative, and (c) The classical notion of free fall does not readily generalize to the quantum regime.

gr-qc↗
arXiv1997

On a New Non-Geometric Element in Gravity

In this essay a generalized notion of flavor-oscillation clocks is introduced. The generalization contains the element that various superimposed mass eigenstates may have different relative orientation of the component of their spin with respect to the rotational axis of the the gravitational source. It is found that these quantum mechanical clocks do not always redshift identically when moved from the gravitational environment of a non-rotating source to the field of a rotating source. The non-geometric contributions to the redshifts may be interpreted as quantum mechanically induced fluctuations over a geometric structure of space-time.

gr-qc↗
arXiv1997

Relativistic Quantum Field Theory of High-Spin Matter Fields: A Pragmatic approach for Hadronic Physics

A consistent phenomenology of the interaction of particles of arbitrary spin requires covariant spinors, field operators, propagators and model interactions. Guided by an approach originally proposed by Weinberg, we construct from group theoretical arguments the (j,0)+(0,j) covariant spinors and the field operators for a massive particles. Specific examples are worked out in the familiar language of the Bjorken and Drell text for the case of the (1,0)+(0,1), (3/2,0)+(0,3/2) and (2,0)+(0,2) matter fields. The m\to 0 limit of the covariant spinors is shown to have the expected structure. The algebra of the γ^{μν} matrices associated with the (1,0)+(0,1) matter fields is presented, and the conserved current derived. The procedure readily extends to higher spins. The causality problem associated with the j\ge 1 wave equations is discussed in detail and a systematic procedure to construct causal propagators is provided. As an example a spin two wave equation satisfied by the (2,0)+(0,2), covariant spinors is found to support not only ten correct and causal solutions, but also thirty physically unacceptable acausal solutions. However, we demonstrate how to construct the Feynman propagator for the higher spin particles directly from the spinors and thus avoid the shortcomings of the wave equation in building a phenomenology. The same exercise is repeated for the (1,0)+(0,1) and (3/2,0)+(0,3/2) matter fields, and the same conclusions obtained. Massless limit is discussed in detail. (Typos uncorrected, Part of the work published and extended in several journal articles, for an important correction see physics/9702005).

nucl-th↗
arXiv1997

Interplay of Non-Relativistic and Relativistic Effects in Neutrino Oscillations

A theoretical structure that involves neutrino mass eigenstates at non relativistic as well as relativistic energies is presented. Using this framework, we find that if the particle X, with mass 33.9 MeV, of the KARMEN collaboration anomaly is identified with the third neutrino mass eigenstate, then the present limit of 23 MeV upper bound on the tau neutrino mass implies |U_{τ3}| < 0.82.

hep-ph↗
arXiv1997

Book Review of Quantum Field Theory by Lewis H. Ryder

Book Review of Quantum Field Theory by Lewis H. Ryder. An observation on Ryder's derivation of Dirac equation is made. The review ends as, "A rare combination of a thorough understanding and appreciation of the essential logical structure of quantum field theory and deep pedagogic skills have intermingled to create a masterpiece on the elementary introduction to quantum field theory in less than five hundred pages... . Without reservations, I give my strongest recommendation to every beginning student of physics to acquire and read Quantum Field Theory by L. H. Ryder."

physics.pop-ph↗
arXiv1996

Notes on the Kinematic Structure of the Three-Flavor Neutrino Oscillation Framework

These notes present a critique of the standard three-flavor neutrino oscillation framwork. The design proposal of the MINOS at Fermilab based on a two mass eigenstate framework may require serious reconsideration if there is strong mixing between all three flavors of neutrinos. For the LSND and KARMEN neutrino oscillation experiments, the amplitude of neutrino oscillation of the ``one mass scale dominance''framework vanishes for certain values of mixing angles as a result of opposite signs of two equal and opposite contributions. Recent astronomical observations leave open the possibility that one of the neutrino mass eigenstates may be non-relativistic in some instances. Neutrino oscillation phenomenology with a superposition of two relativistic, and one non-relativistic, mass eigenstates is constructed. It is concluded that if the transition from the non-relativistic to the relativistic regime happens for energies relevant to the Reactor and the LSND neutrino oscillation experiments then one must consider an ab intio analysis of the existing data.

hep-ph↗
arXiv1995

A New Type of Massive Spin-One Boson: and its Relation with Maxwell Equations

First, we show that in the $(1,0)\oplus(0,1)$ representation space there exist not one but two theories for charged particles. In the Weinberg construct, the boson and its antiboson carry {\it same} relative intrinsic parity, whereas in our construct the relative intrinsic parities of the boson and its antiboson are {\it opposite}. These results originate from the commutativity of the operations of Charge conjugation and Parity in Weinberg's theory, and from the anti-commutativity of the operations of Charge conjugation and Parity in our theory. We thus claim that we have constructed a first non-trivial quantum theory of fields for the Wigner-type particles. Second, the massless limit of both theories seems formally identical and suggests a fundamental modification of Maxwell equations. At its simplest level, the modification to Maxwell equations enters via additional boundary condition(s).

hep-th↗
arXiv1995

Theory of Neutral Particles: Mclennan-Case Construct for Neutrino, Its Generalization, and a New Wave Equation

Continuing our recent argument where we constructed a FNBWW-type spin-$1$ boson having opposite relative intrinsic parity to that of the associated antiparticle, we now study eigenstates of the Charge Conjugation operator. Based on the observation that if $ϕ_{_{L}}(p^μ)$ transforms as a $(0,\,j)$ spinor under Lorentz boosts, then $Θ_{[j]}\,ϕ_{_{L}}^\ast(p^μ)$ transforms as a $(j,\,0)$ spinor (with a similar relationship existing between $ϕ_{_{R}}(p^μ)$ and $Θ_{[j]}\,ϕ_{_{R}}^\ast(p^μ)$; where $ Θ_{[j]}\,{\bf J}\,Θ_{[j]}^{-1}\,=\,-\,{\bf J}^\ast $ with $Θ_{[j]}$ the well known Wigner matrix involved in the operation of time reversal) we introduce McLennan-Case type $(j,\,0)\oplus(0,\,j)$ spinors. Relative phases between $ϕ_{_{R}}(p^μ)$ and $Θ_{[j]}\,ϕ_{_{R}}^\ast(p^μ)$, and $Θ_{[j]}\,ϕ_{_{L}}^\ast(p^μ)$ and $ϕ_{_{L}}(p^μ)$, turn out to have physical significance and are fixed by appropriate requirements. Explicit construction, and a series of physically relevant properties, for these spinors are obtained for spin-$1/2$ and spin-$1$ culminating in the construction of a new wave equation and introduction of Dirac-like and Majorana-like quantum fields.

hep-th↗
arXiv1994

Parity and Fermions in Front-Form: An Unexpected Result

We show that under the operation of parity the {\it front-form} $(1/2,\,0)$ and $(0,\,1/2)$ Weyl spinors (massive or massless) do not get interchanged. This has the important consequence that if a front-form theory containing $(1/2,\,0)\oplus(0,\,1/2)$ representation space has to be parity covariant then one must study the evolution of a physical system not only along $x^+$ but also along the $x^-$ direction. As a result of our analysis, we find an indication that there may be no halving of the degrees of freedom in the front form of field theories.

hep-th↗
arXiv1994

Quantum Measurement, Gravitation, and Locality

This essay argues that when measurement processes involve energies of the order of the Planck scale, the fundamental assumption of locality may no longer be a good approximation. Idealized position measurements of two distinguishable spin-$0$ particles are considered. The measurements alter the space-time metric in a fundamental manner governed by the commutation relations $[x_i\,\,p_j]= i\hbar\,δ_{ij}$ and the classical field equations of gravitation. This {\it in-principle} unavoidable change in the space-time metric destroys the commutativity (and hence locality) of position measurement operators.

gr-qc↗
arXiv1993

Space-Time Symmetries: P and CP Violation

We begin with a few remarks on an explicit construction of a Bargmann-Wightman-Wigner-type quantum field theory [Phys. Lett. B {\bf 316}, 102 (1993)] in which bosons and associated antibosons have opposite relative intrinsic parities. We then construct $(1,0)\oplus(0,1)$ Majorana ($CP$ self conjugate) and Majorana-like ($CΓ^5$ self conjugate, $Γ^5=$ chirality operator) fields. We point out that this new structure in the space time symmetries may be relevant to $P$ and $CP$ violation.

hep-th↗