Cosmology with a Nonlinear Born-Infeld type Scalar Field

Recent many physicists suggest that the dark energy in the universe might result from the Born-Infeld(B-I) type scalar field of string theory. The universe of B-I type scalar field with potential can undergo a phase of accelerating expansion. The corresponding equation of state parameter lies in the range of $\displaystyle -1<\omega<-{1/3}$. The equation of state parameter of B-I type scalar field without potential lies in the range of $0\leq\omega\leq1$. We find that weak energy condition and strong energy condition are violated for phantom B-I type scalar field. The equation of state parameter lies in the range of $\omega<-1$.Comment: 10 pages without figure

Nonlinear electrodynamics and the gravitational redshift of highly magnetised neutron stars

The idea that the nonlinear electromagnetic interaction, i. e., light propagation in vacuum, can be geometrized was developed by Novello et al. (2000) and Novello & Salim (2001). Since then a number of physical consequences for the dynamics of a variety of systems have been explored. In a recent paper Mosquera Cuesta & Salim (2003) presented the first astrophysical study where such nonlinear electrodynamics (NLEDs) effects were accounted for in the case of a highly magnetized neutron star or pulsar. In that paper the NLEDs was invoked {\it a l\`a} Euler-Heisenberg, which is an infinite series expansion of which only the first term was used for the analisys. The immediate consequence of that study was an overall modification of the space-time geometry around the pulsar, which is ``perceived'', in principle, only by light propagating out of the star. This translates into an significant change in the surface redshift, as inferred from absorption (emission) lines observed from a super magnetized pulsar. The result proves to be even more dramatic for the so-called magnetars, pulsars endowed with magnetic ($B$) fields higher then the Schafroth quantum electrodynamics critical $B$-field. Here we demonstrate that the same effect still appears if one calls for the NLEDs in the form of the one rigorously derived by Born & Infeld (1934) based on the special relativistic limit for the velocity of approaching of an elementary particle to a pointlike electron [From the mathematical point of view, the Born & Infeld (1934) NLEDs is described by an exact Lagrangean, whose dynamics has been successfully studied in a wide set of physical systems.].Comment: Accepted for publication in Month. Not. Roy. Ast. Soc. latex file, mn-1.4.sty, 5 pages, 2 figure

Il-palk Malti

L-awtur jitkellem dwar is-sitwazzjoni preżenti ta’ żmienu fir-rigward tal-kitba teatrali Maltija.N/

Nonperturbative calculation of Born-Infeld effects on the Schroedinger spectrum of the hydrogen atom

We present the first nonperturbative numerical calculations of the nonrelativistic hydrogen spectrum as predicted by first-quantized electrodynamics with nonlinear Maxwell-Born-Infeld field equations. We also show rigorous upper and lower bounds on the ground state. When judged against empirical data our results significantly restrict the range of viable values of the new electromagnetic constant which is introduced by the Born-Infeld theory. We assess Born's own proposal for the value of his constant.Comment: 4p., 2 figs, 1 table; submitted for publicatio

Coupled dynamics of atoms and radiation pressure driven interferometers

We consider the motion of the end mirror of a cavity in whose standing wave mode pattern atoms are trapped. The atoms and the light field strongly couple to each other because the atoms form a distributed Bragg mirror with a reflectivity that can be fairly high. We analyze how the dipole potential in which the atoms move is modified due to this backaction of the atoms. We show that the position of the atoms can become bistable. These results are of a more general nature and can be applied to any situation where atoms are trapped in an optical lattice inside a cavity and where the backaction of the atoms on the light field cannot be neglected. We analyze the dynamics of the coupled system in the adiabatic limit where the light field adjusts to the position of the atoms and the light field instantaneously and where the atoms move much faster than the mirror. We calculate the side band spectrum of the light transmitted through the cavity and show that these spectra can be used to detect the coupled motion of the atoms and the mirror.Comment: 11 pages; 13 figures; two added references and other minor correction

Large tunable photonic band gaps in nanostructured doped semiconductors

A plasmonic nanostructure conceived with periodic layers of a doped semiconductor and passive semiconductor is shown to generate spontaneously surface plasmon polaritons thanks to its periodic nature. The nanostructure is demonstrated to behave as an effective material modeled by a simple dielectric function of ionic-crystal type, and possesses a fully tunable photonic band gap, with widths exceeding 50%, in the region extending from mid-infra-red to Tera-Hertz.Comment: 6 pages, 4 figures, publishe

Polaron action for multimode dispersive phonon systems

Path-integral approach to the tight-binding polaron is extended to multiple optical phonon modes of arbitrary dispersion and polarization. The non-linear lattice effects are neglected. Only one electron band is considered. The electron-phonon interaction is of the density-displacement type, but can be of arbitrary spatial range and shape. Feynman's analytical integration of ion trajectories is performed by transforming the electron-ion forces to the basis in which the phonon dynamical matrix is diagonal. The resulting polaron action is derived for the periodic and shifted boundary conditions in imaginary time. The former can be used for calculating polaron thermodynamics while the latter for the polaron mass and spectrum. The developed formalism is the analytical basis for numerical analysis of such models by path-integral Monte Carlo methods.Comment: 9 page

The mystery of relationship of mechanics and field in the many-body quantum world

We have revealed three fatal errors incurred from a blind transferring of quantum field methods into the quantum mechanics. This had tragic consequences because it produced crippled model Hamiltonians, unfortunately considered sufficient for a description of solids including superconductors. From there, of course, Fr\"ohlich derived wrong effective Hamiltonian, from which incorrect BCS theory arose. 1) Mechanical and field patterns cannot be mixed. Instead of field methods applied to the mechanical Born-Oppenheimer approximation we have entirely to avoid it and construct an independent and standalone field pattern. This leads to a new form of the Bohr's complementarity on the level of composite systems. 2) We have correctly to deal with the center of gravity, which is under the field pattern "materialized" in the form of new quasipartiles - rotons and translons. This leads to a new type of relativity of internal and external degrees of freedom and one-particle way of bypassing degeneracies (gap formation). 3) The possible symmetry cannot be apriori loaded but has to be aposteriori obtained as a solution of field equations, formulated in a general form without translational or any other symmetry. This leads to an utterly revised view of symmetry breaking in non-adiabatic systems, namely Jahn-Teller effect and superconductivity. These two phenomena are synonyms and share a unique symmetry breaking.Comment: 24 pages, 9 sections; remake of abstract, introduction and conclusion; more physics, less philosoph

Asymptotic Search for Ground States of SU(2) Matrix Theory

We introduce a complete set of gauge-invariant variables and a generalized Born-Oppenheimer formulation to search for normalizable zero-energy asymptotic solutions of the Schrodinger equation of SU(2) matrix theory. The asymptotic method gives only ground state candidates, which must be further tested for global stability. Our results include a set of such ground state candidates, including one state which is a singlet under spin(9).Comment: 51 page

Born-Infeld-Einstein theory with matter

The field equations associated with the Born-Infeld-Einstein action including matter are derived using a Palatini variational principle. Scalar, electromagnetic, and Dirac fields are considered. It is shown that an action can be chosen for the scalar field that produces field equations identical to the usual Einstein field equations minimally coupled to a scalar field. In the electromagnetic and Dirac cases the field equations reproduce the standard equations only to lowest order. The spherically symmetric electrovac equations are studied in detail. It is shown that the resulting Einstein equations correspond to gravity coupled to a modified Born-Infeld theory. It is also shown that point charges are not allowed. All particles must have a finite size. Mass terms for the fields are also considered.Comment: 12 pages, LaTe