118337761
Manifest dyality invariance in electrodynamics and the cabibbo-ferrari theory of magnetic monopoles
SummaryOne of the intrinsic symmetry properties of the Maxwell-Lorentz theory of electrodynamics is the invariance of the theory under « dyality » transformation, that is, a dual transformation on fieldsand sourcessimultaneously. In this paper we give a manifestly dyality-invariant formulation of electrodynamics. This is done by expressing the electromagnetic-field tensors in terms of an antisymmetric tensor of rank two, called a Hertz tensor, consisting of electric and magnetic Hertz vector potentials. An equation is derived which relates the electromagnetic fields when sources consist of electric charges only, magnetic charges only, and both. The present formalism provides a natural physical basis for the Cabibbo-Ferrari theory in which two four-vector potentials and a mixed gauge transformation between them are introduced.RiassuntoUna delle proprietà di simmetria intrinseca della teoria di Maxwell-Lorentz dell’elettrodinamica è l’invarianza della teoria rispetto alle trasformazioni di «dialità», cioè una trasformazione duale sui campie le sorgenticontemporaneamente. In questo articolo si espone una formulazione dell’elettrodinamica che è manifestamente invariante rispetto alla dialità. Si fà ciò esprimendo i tensori del campo elettromagnetico in termini di un tensore antisimmetrico di rango due, detto tensore di Hertz, consistente di potenziali del vettore di Hertz elettrico e magnetico. Si deduce un’equazione che mette in relazione i campi magnetici quando le sorgenti consistono di sole cariche elettriche, di sole cariche magnetiche, o di entrambe. Questo formalismo fornisce una naturale base fisica per la teoria di Cabibbo-Ferrari, in cui si introducono due potenziali quadrivettori e una trasformazione di gauge mista tra essi.РеэюмеОдно иэ свойств внутренней симметрии Максвелл-Лорентцевс кой теории злектродинамики представляет инвариантность теории относительно преобраэования «диальности», т.е. одновременное дуальное преобраэование полей и источников. В зтой статье мы приводим формулировку злектродинамики, обладаюшую явной диальной инвариантностью. Это достигается эа счет выражения тенэора злектромагнитного поля череэ антисимметричный тенэор второго ранга, наэываемый тенэором Герца, который состоит иэ злектрического и магнитного векторных потенциалов Герца. Выводится уравнение, которое свяэывает злектромагнитные поля, когда источники состоят только иэ злектрических эарядов, только иэ магнитных эарядов и тех и других. Предлагаемый формалиэм обеспечивает естественную фиэическую основу для теории Кабиббо-Феррари, в которой вводятся два четырех-векторных потенциала и смещанное калибровочное преобраэование между ними.
123307684
Hadronic regge sequences as primitive realizations of SL(3,R) symmetry☆
Abstract Four primitive infinite dimensional unitary representations of the group of rotations and deformations - SL(3,R) - are constructed and associated with the four Regge trajectories: π, ϱ, N, Δ. The model predicts E2 transition moments and a power law for E versus j consistent with the Chew-Frautschi relation E∼j 1 2 .
121619492
A possible mechanism for CP nonconservation
120561444
Comment on the paper entitled «On the Poincaré noninvariance of a recent alternative to the Dirac equation»
120403374
THREE-TRIPLET MODEL WITH DOUBLE SU(3) SYMMETRY
122507140
Diquark color excitation and the narrow resonances
The new narrow resonances are interpreted in the three-triplet model with integral baryon numbers as diquark color excitations of the qq +- q-barq-bar type. Hadronic decays, ..gamma.. transitions, and coupling to ..gamma.. occur through impurity qq-bar admixtures. Except for the coupling to ..gamma.., all decay rates are suppressed. The enhancements above 4 GeV in hadronic cross sections are attributed to qq-bar color octets or still higher diquark levels. (AIP)
118178605
SL(2,C) Chern–Simons theory, a non-planar graph operator, and 4D quantum gravity with a cosmological constant: Semiclassical geometry
Abstract We study the expectation value of a nonplanar Wilson graph operator in SL ( 2 , C ) Chern–Simons theory on S 3 . In particular we analyze its asymptotic behavior in the double-scaling limit in which both the representation labels and the Chern–Simons coupling are taken to be large, but with fixed ratio. When the Wilson graph operator has a specific form, motivated by loop quantum gravity, the critical point equations obtained in this double-scaling limit describe a very specific class of flat connection on the graph complement manifold. We find that flat connections in this class are in correspondence with the geometries of constant curvature 4-simplices. The result is fully non-perturbative from the perspective of the reconstructed geometry. We also show that the asymptotic behavior of the amplitude contains, at the leading order, an oscillatory part proportional to the Regge action for the single 4-simplex in the presence of a cosmological constant. In particular, the cosmological term contains the full-fledged curved volume of the 4-simplex. Interestingly, the volume term stems from the asymptotics of the Chern–Simons action. This can be understood as arising from the relation between Chern–Simons theory on the boundary of a region, and a theory defined by an F 2 action in the bulk. Another peculiarity of our approach is that the sign of the curvature of the reconstructed geometry, and hence of the cosmological constant in the Regge action, is not fixed a priori, but rather emerges semiclassically and dynamically from the solution of the equations of motion. In other words, this work suggests a relation between 4-dimensional loop quantum gravity with a cosmological constant and SL ( 2 , C ) Chern–Simons theory in 3 dimensions with knotted graph defects.
6895472
Generating entangled photons from the vacuum by accelerated measurements: Quantum-information theory and the Unruh-Davies effect
quantum communications between accelerated and stationary observers. We find that the projective measurement by a uniformly accelerated observer can excite real particles from the vacuum in the inertial frame, even if no additional particles are created by the measurement process in the accelerating frame. Furthermore, we show that the particles created by this accelerating measurement can be highly entangled in the inertial frame, and it is also possible to use this process to generate even maximally entangled two-qubit states by a certain arrangement of measurements. As a by-product of our analysis, we also show that a single qubit of information can be perfectly transmitted from the accelerating observer to the inertial one. In principle, such an effect could be exploited in designing an entangled-state generator for quantum communication.
119719561
Semiclassical analysis of spinfoam model with a small Barbero-Immirzi parameter
We study the semiclassical behavior of Lorentzian Engle-Pereira-Rovelli-Livine (EPRL) spinfoam model, by taking into account of the sum over spins in the large spin regime. The large spin parameter \lambda and small Barbero-Immirzi parameter \gamma are treated as two independent parameters for the asymptotic expansion of spinfoam state-sum (such an idea was firstly pointed out in arXiv:1105.0216). Interestingly, there are two different spin regimes: 1 \gamma^{-2}. The model in two spin regimes has dramatically different number of effective degrees of freedom. In 1 \gamma^{-2}, only small deficit angle is allowed |\Theta_f|<<\gamma^{-1}\lambda^{1/2}$ mod 4\pi Z. When spins go even larger, only zero deficit angle mod 4\pi Z is allowed asymptotically. In the transition of the two regimes, only the configurations with small deficit angle can contribute, which means one need a large triangulation in order to have oscillatory behavior of the spinfoam amplitude.
118545643
Canonical path-integral measures for Holst and Plebanski gravity: II. Gauge invariance and physical inner product
This paper serves as a continuation for the discussion in Engle et al (2010, Class. Quantum Grav. 27 245014). We analyze the invariance properties of the gravity path-integral measure derived from canonical framework and discuss which path-integral formula may be employed in the concrete computation e.g. constructing a spin-foam model, so that the final model can be interpreted as a physical inner product in the canonical theory. This paper is divided into two parts, the first part is concerning the gauge invariance of the canonical path-integral measure for gravity from the reduced phase space quantization. We show that the path-integral measure is invariant under all the gauge transformations generated by all the constraints. These gauge transformations are the local symmetries of the gravity action, which is implemented without anomaly at the quantum level by the invariant path-integral measure. However, these gauge transformations coincide with the spacetime diffeomorphisms only when the equations of motion are imposed. But the path-integral measure is not invariant under spacetime diffeomorphisms, i.e. the local symmetry of spacetime diffeomorphisms become anomalous in the reduced phase space path-integral quantization. In the second part, we present a path-integral formula, which formally solves all the quantum constraint equations of gravity, and further results in a rigging map in the sense of refined algebraic quantization (RAQ). Then we give a formal path-integral expression of the physical inner product in loop quantum gravity (LQG). This path-integral expression is simpler than the one from reduced phase space quantization, since all the gauge-fixing conditions are removed except the time gauge. The resulting path-integral measure is different from the product Lebesgue measure up to a local measure factor containing both the spacetime volume element and the spatial volume element. This formal path-integral expression of the physical inner product can be a starting point for constructing a spin-foam model.
16629504
Five-dimensional Brans-Dicke theory and cosmic acceleration
We consider a 5-dimensional scalar-tensor theory which is a direct generalization of the original 4-dimensional Brans-Dicke theory to five dimensions. By assuming that there is a hypersurface-orthogonal spacelike Killing vector field in the underlying 5-dimensional spacetime, the theory is reduced to a 4-dimensional theory where the 4-metric is coupled with two scalar fields. The cosmological implication of this reduced theory is then studied in the Robertson-Walker model. It turns out that the two scalar fields may account naturally for the present accelerated expansion of our universe. The observational restriction of the reduced cosmological model is also analyzed.