Renormalization of the Wess-Zumino model with a nonminimal coupling to an external supergravity field

The renormalization structure of the parameters corresponding to nonminimal coupling between a scalar superfield and an external supergravity field is studied. The renormalization group equations are obtained for the corresponding effective charges, and their asymptotic behavior is investigated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 62–68, July, 1988.     

Spinless bosons embedded in a vector Duffin-Kemmer-Petiau oscillator

Some properties of minimal and nonminimal vector interactions in the Duffin-Kemmer-Petiau (DKP) formalism are discussed. The conservation of the total angular momentum for spherically symmetric nonminimal potentials is derived from its commutation properties with each term of the DKP equation and the proper boundary conditions on the spinors are imposed. It is shown that the space component of the nonminimal vector potential plays a crucial role for the confinement of bosons. The exact solutions for the vector DKP oscillator (nonminimal vector coupling with a linear potential which exhibits an equally spaced energy spectrum in the weak-coupling limit) for spin-0 bosons are presented in a closed form and it is shown that the spectrum exhibits an accidental degeneracy.     

Heisenberg Equations of Motion in a Nonabelian Gauge Theory

Heisenberg type equations of motion are established in a nonabelian gauge theory with minimal and nonminimal couplings and various relativistic particle equations of motion are derived from them. These equations for pointlike particles possessing a nonabelian gauge interaction (chosen for definiteness to be of SO(4,1) type) ore obtained in classical limit, ħ → 0, or in a semiclassical limit in which contributions of first order in ħ are retained. As a byproduct of the formalism, which can be applied to an arbitrary gauge group, a simple derivation of the Lorentz equation and the Bargmann-Michel-Telegdi equation from spinor electrodynamics with anomalous (i.e. nonminimal) coupling is given starting from the associated quantum mechanical Heisenberg equations of motion and specializing the gauge group to the electromagnetic U(1) group.     

Asymptotically free models in curved space-time and behavior of effective charges in a strong gravitational field

A theory of gauge, spinor, and scalar fields interacting in curves space is considered. Equations are obtained for effective charges corresponding to the parameters of a nonminimal coupling of gravitational and scalar fields. It is shown that in a strong gravitational field the values of these parameters are dictated by the structure of the theory.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 86–91, January, 1985.     

The extended Nambu-Jona-Lasinio model with separable interaction: Low energy pion physics and pion-nucleon form factor

A Lagrangian formulation of the Nambu-Jona-Lasinio model with separable interaction is given. The electromagnetic interaction is introduced in a nonminimal way to the nonlocal quark current. Various choices of the vertex form factors characterizing the composite structure of mesons and baryon are investigated. We find that the physical observables depend very weakly on form factor shapes. We calculate the πNN form factor considering nucleon as a three-quark system.     

Inflation with an antisymmetric tensor field

We investigate the possibility of inflation with models of antisymmetric tensor field having minimal and nonminimal couplings to gravity. Although the minimal model does not support inflation, the nonminimal models, through the introduction of a nonminimal coupling to gravity, can give rise to stable de-Sitter solutions with a bound on the coupling parameters. The values of field and coupling parameters are sub-planckian. Slow roll analysis is performed and slow-roll parameters are defined which can give the required number of e-folds for sufficient inflation. Stability analysis has been performed for perturbations to antisymmetric field while keeping the metric unperturbed, and it is found that only the sub-horizon modes are free of ghost instability for de-Sitter space.     

What Can We Learn from Nonminimally Coupled Scalar Field Cosmology?

A novel exploration of nonminimally coupled scalar field cosmology is proposedin the framework of spatially flat Friedmann—Robertson—Walker spaces forarbitrary scalar field potentials V() and values of the nonminimal couplingconstant . This approach is self-consistent in the sense that the equation of stateof the scalar field is not prescribed a priori, but is rather deduced together withthe solution of the field equations. The role of nonminimal coupling appears tobe essential. A dimensional reduction of the system of differential equations leadsto the result that chaos is absent in the dynamics of a spatially flat FRW universewith a single scalar field. The topology of the phase space is studied and revealsan unexpected involved structure: according to the form of the potential V()and the value of the nonminimal coupling constant , dynamically forbiddenregions may exist. Their boundaries play an important role in the topologicalorganization of the phase space of the dynamical system. New exact solutionssharing a universal character are presented; one of them describes a nonsingularuniverse that exhibits a graceful exit from, and entry into, inflation. This behaviordoes not require the presence of the cosmological constant. The relevance of thissolution and of the topological structure of the phase space with respect to anemergence of the universe from a primordial Minkowski vacuum, in an extendedsemiclassical context, is shown.     

Inflation mechanism in asymptotic noncommutative geometry

The possibility of having an inflationary epoch within a noncommutative geometry approach to unifying gravity and the Standard Model is demonstrated. This inflationary phase occurs without the need to introduce ad hoc additional fields or potentials, rather it is a consequence of a nonminimal coupling between the geometry and the Higgs field.     

Nonlinear electrodynamics in space-times with torsion

A nonminimal and nongauge invariant descirption of nonlinear electrodynamics in space-times with torsion is given. It is shown that in the case of the Weitzenböck teleparallel space-time, massive photons are produced by a mechanism which involves the nonminimal coupling constant and the divergence of the torsion vector.On leave of absence from: Grupo de Relatividade e Teoria de Campo, Instituto de Fisica — UERJ, Departamento de Fisica Teorica, 20550 Maracan, Rio de Janeiro, Brazil     

Criterion for and the physical interpretation of minimal and nonminimal interactions

A classification of currents for finite- and infinite-component wave equations is proposed depending on their algebraic and convective nature. Algebraic terms with a consistent one-particle interpretation constitute the minimal interactions. The nonminimal interactions are interpreted as effective c-number currents describing many particle effects and/or composite structures. A number of applications are treated.     

Radiative corrections to Higgs boson masses in supersymmetric models

The effect of radiative corrections on the Higgs masses and couplings in supersymmetric models is summarized. Radiative corrections in both the minimal and nonminimal models are discussed. It is pointed out that large singlet Higgs vacuum expectation values are screened out from the radiative corrections to the lightest Higgs mass in nonminimal models. In supersymmetric models the crucial mass limit for the Higgs search may be around 150 GeV.     

The Einstein–Cartan–Elko system

The present paper analyses the Einstein‐Cartan theory of gravitation with Elko spinors as sources of curvature and torsion. After minimally coupling the Elko spinors to torsion, the spin angular momentum tensor is derived and its structure is discussed. It shows a much richer structure than the Dirac analogue and hence it is demonstrated that spin one half particles do not necessarily yield only an axial vector torsion component. Moreover, it is argued that the presence of Elko spinors partially solves the problem of minimally coupling Maxwell fields to Einstein‐Cartan theory.     

Radiative corrections to Higgs boson masses in supersymmetric models

The effect of radiative corrections on the Higgs masses and couplings in supersymmetric models is summarized. Radiative corrections in both the minimal and nonminimal models are discussed. It is pointed out that large singlet Higgs vacuum expectation values are screened out from the radiative corrections to the lightest Higgs mass in nonminimal models. In supersymmetric models the crucial mass limit for the Higgs search may be around 150 GeV.     

Multistability of impact, utility and threshold concepts of binary choice models

The decision making problem in the context of binary choice is considered by means of impact function, utility function and threshold model approaches. The properties of generalized impact function and utility function are examined; it is shown that these two approaches are equivalent. Their relation to the threshold model is studied and the correspondence between respective cumulative distribution functions is displayed. The stationary state corresponding to the thermodynamic equilibrium is determined within mean field approximation. Multistability of the stationary state is expressed in terms of the distribution function of the random variable of impact/utility function. The correspondence with statistical physics predictions for Ising model is discussed: logistic distribution leads to the mean-field result, i.e. Curie-Weiss approximation. Variations of the distribution functions and/or other model parameters, of social character, self-support, nonlinearity of social interactions, etc., would break the direct correspondence to statistical physics of Ising model, leading in particular cases to richer structure of the multistability.     

Numerical study on schramm-loewner evolution in nonminimal conformal field theories

The Schramm-Loewner evolution (SLE) is a powerful tool to describe fractal interfaces in 2D critical statistical systems, yet the application of SLE is well established for statistical systems described by quantum field theories satisfying only conformal invariance, the so-called minimal conformal field theories (CFTs). We consider interfaces in Z(N) spin models at their self-dual critical point for N = 4 and N = 5. These lattice models are described in the continuum limit by nonminimal CFTs where the role of a ZN symmetry, in addition to the conformal one, should be taken into account. We provide numerical results on the fractal dimension of the interfaces which are SLE candidates for nonminimal CFTs. Our results are in excellent agreement with some recent theoretical predictions.     

Solvation properties of non-polar amino acids in water and methanol: a molecular dynamics study

Solvation properties of the amino acids alanine, valine, leucine and phenylalanine in water and in methanol at infinite dilution have been studied by using molecular dynamics simulations. The free energy transfer of the solutes from water to methanol has been calculated by means of a slow-growth technique and the results compared with diverse hydrophobicity scales available in the literature. Chothia's linear relation between the accessible surface area and the hydrophobicity is shown. The line obtained has a slope equivalent to 49cal mol^?1 Å^?2. The radial distribution of solvent molecules around the amino acids residues is considered, and a comparison is made of the number of hydrogen bonds formed between water molecules in the presence and in the absence, respectively, of the amino acids. The calculations show clearly that the solvation structure near the non-polar amino acids is richer for methanol than for water.     

Cosmological model with nonminimal derivative coupling of scalar fields in five dimensions

We study a nonminimal derivative coupling (NMDC) of scalar field, where the scalar field is coupled to curvature tensor in the five dimensional universal extra dimension model. We apply the Einstein equation and find its solution. First, we consider a special case of pure free scalar field without NMDC and we find that for static extradimension, the solution is equivalent to the standard cosmology with stiff matter. For a general case of pure free scalar field with NMDC, we find that the de Sitter solution is the solution of our model. For this solution, the scalar field evolves linearly in time. In the limit of small Hubble parameter, the general case give us the same solution as in the pure free scalar field. Finally, we perform a dynamical analysis to determine the stability of our model. We find that the extradimension, if it exist, can not be static and always shrinks with the expansion of four dimensional spacetime.     

MiniBooNE and LSND data: non-standard neutrino interactions in a (3+1) scheme versus (3+2) oscillations

Journal of High Energy Physics - We consider the cosmology of a model in which the dark matter is part of a nonminimal hidden sector which is not in thermal equilibrium with the standard model...     

Theories of gravitation with nonminimal coupling of matter and the gravitational field

The foundations of a theory of nonminimal coupling of matter and the gravitational field in the framework of Riemannian (or Riemann-Cartan) geometry are presented. In the absence of matter, the Einstein vacuum field equations hold. In order to allow for a Newtonian limit, the theory contains a new parameter l₀ of dimension length. For systems with finite total mass, l₀ is set equal to the Schwarzschild radius.Slightly extended version of a paper presented at the 14th Jena Seminar on Relativistic Physics, Georgenthal, November 15–21, 1982.