bluuebunny/crossref_metadata_2025 huggingface dataset:
Hamiltonian Formulation of Quantum Hall Skyrmions with Hopf Term
Authors: Chakraborty B. , Govindarajan T. R.
Published: October 2003

We study the nonrelativistic nonlinear sigma model with Hopf term in this letter. This is an important issue because of its relation to the currently interesting studies in skyrmions in quantum Hall systems. We perform the Hamiltonian analysis of this system in CP1 variables. When the coefficient of the Hopf term becomes zero we get the Landau–Lifshitz description of the ferromagnets. The addition of Hopf term dramatically alters the Hamiltonian analysis. The spin algebra is modified giving a new structure and interpretation to the system. We point out momentum and angular momentum generators and new features they bring into the system.
Negative-Dimensional Group Extrapolation and Dualities in N=1 Supersymmetric Gauge Theories
Authors: Maru Nobuhito , Kitakado Shinsaku
Published: October 2003

We point out that the similarities in N=1 supersymmetric SO, SP gauge theories can be explained by using the trick of extrapolating the groups to the negative dimensions. One of the advantages of this trick is that anomaly matching is automatically satisfied. We also give a comment on the problem which one encounters when applying the trick of negative-dimensional group to Spin group duality.
Peierls Model and Vacuum Structure in the N = 2 Supersymmetric Field Theories
Authors: Gorsky A.
Published: October 2003

We suggest the quasiparticle picture behind the integrable structure of N=2 SYM theory which arises if the Lax operator is considered as a Hamiltonian for the fermionic system. We compare the meaning of BPS states with the one coming from the D-brane interpretation and give some evidence for the compositeness of the self-dual strings. The temperature phase transition with the disappearance of the mass gap is conjectured.
Integrability, Fusion, and Duality in the Elliptic Ruijsenaars Model
Authors: Hikami Kazuhiro , Komori Yasushi
Published: October 2003

The generalized elliptic Ruijsenaars models, which are regarded as a difference analog of the Calogero–Sutherland–Moser models associated with the classical root systems are studied. The integrability and the duality using the fusion procedure of operator-valued solutions of the Yang–Baxter equation and the reflection equation are shown. In particular a new integrable difference operator of type-D is proposed. The trigonometric models are also considered in terms of the representation of the affine Hecke algebra.
Classical Entropy of N=2 Black Holes: The Minimal Coupling Case
Authors: Sabra W. A.
Published: October 2003

We discuss the entropy and the transformation properties of classical extremal N=2 black hole solutions in supergravity theories associated with the minimal coupling models CP (n - 1,1). The entropy is given by a manifestly invariant quantity under the embedding of the duality group SU (1,n) into Sp (2n + 2) which is a symmetry of the classical BPS mass formula.
Higher-Genus Corrections to Black-String Solution
Authors: Iofa M. Z.
Published: October 2003

One-string-loop (torus topology) corrections to black-string backgrounds corresponding to gauged SL (2,R)× R/R WZW model are calculated using β-function equations derived from string-loop-corrected effective action. Loop-corrected backgrounds are used to calculate ADM mass of the black string.
Supersymmetric Quantum Mechanics and the Equivalent Classical Transformation
Authors: Neto A. Agostinho , Filho E. Drigo
Published: October 2003

In the usual supersymmetric quantum mechanics, the supercharges change the eigenfunction from the bosonic to fermionic sector and conversely. The classical correspondent of this transformation is shown to be the addition of a total time derivative of a purely imaginary function to the Lagrangian function of the system.
Effective Lagrangian and Static Black Holes in 2-D Dilatonic Gravity Inspired by Quantum Effects
Authors: Nojiri Shin'ichi , Odintsov Sergei D.
Published: October 2003

We study the effective action in 2-D dilaton-Maxwell quantum gravity. Working with the one-loop renormalizable subset of such theories, we construct the improved effective Lagrangian which contains curvature under logarithm. This effective Lagrangian leads to new classical dilatonic gravity inspired by quantum effects. The static black holes (BH) solutions which may play the role of a remnant after the Hawking radiation for such theory are carefully investigated. The effective Lagrangian for Gross–Neveu-dilaton gravity is also constructed (in 1/N expansion).
Deconfinement in QCD with Dynamical Quarks
Authors: Borisenko O. , Faber M. , Zinovjev G.
Published: October 2003

We study the phase structure of full QCD within the canonical ensemble (CE) with respect to triality in a lattice formulation. The procedure to calculate the effective potentials (EP) in the CE is given. We calculate the EP for the three-dimensional SU(2) gauge model at finite temperature in the strong coupling region. The potential exhibits a genuine deconfinement phase transition unlike the similar potential obtained in the grand canonical ensemble (GCE). Furthermore, we investigate the EP with the chiral condensate included. Contrary to other recent results we find chiral symmetry restoration in all triality sectors. Dealing with massless staggered fermions we observe chiral symmetry restoration accompanying a deconfinement phase transition of first-order. Above the critical point, besides two Z(2) symmetric "deconfining" vacua there exists a metastable "confining" vacuum in a wide region of the (Nt,γ)-plane. Such a picture could be interpreted as an indication for a mixed state of hadrons and quarks in the vicinity of the critical line.
The Post-Newtonian Approximation and the Shells Oscillations
Authors: Santoro Fernando , Neira Luis , Lara Luis , Aquilano Roberto
Published: October 2003

We use the post-Newtonian approximation to show that the shells oscillations could be very important in the physics of astronomical objects with neutron stars. The conclusions of Ref. 1 are confirmed.
The Finite Temperature Effective Potential for Local Composite Operators
Authors: Okopińska Anna
Published: October 2003

The method of the effective action for the composite operators Φ2(x) and Φ4(x) is applied to the thermodynamics of the scalar quantum field with λΦ4 interaction. An expansion of the finite temperature effective potential in powers of ℏ provides successive approximations to the free energy with an effective mass and an effective coupling determined by the gap equations. The numerical results are studied in the spacetime of one dimension when the theory is equivalent to the quantum mechanics of an anharmonic oscillator. The approximations to the free energy show quick convergence to the exact result.
Anisotropic Correlated Electron Model Associated with the Temperley–Lieb Algebra
Authors: Foerster Angela , Links Jon , Roditi Itzhak
Published: October 2003

We present an anisotropic correlated electron model on a periodic lattice, constructed from an R-matrix associated with the Temperley–Lieb algebra. By modification of the coupling of the first and last sites we obtain a model with quantum algebra invariance.
BRST Formulation of Partition Function Constraints
Authors: Alfaro Jorge , Bering Klaus , Damgaard Poul H.
Published: October 2003

We show that the constraints on the generating functional have direct BRST-extensions in terms of nilpotent operators Δ that annihilate this generating functional, and which may be of arbitrarily high order. The free energy F in the presence of external sources thus satisfies a "Master Equation" which is described in terms of a tower of higher antibrackets.
N=3 and N=4 Two-Form Supergravities
Authors: Kadoyoshi Tomoko , Nojiri Shin'ichi
Published: October 2003

We construct the Lagrangians of N=3 and N=4 two-form supergravities. The two-form gravity theories are classically equivalent to the Einstein gravity theories and can be formulated as gauge theories. The gauge algebras used here can be identified with the subalgebra of N=3 superconformal algebra and SU (2)× SU (2)× U(1) -extended N=4 superconformal algebra.
A Locally Supersymmetric Action for the Scalar Particle
Authors: Bastianelli Fiorenzo , Consoli Luca
Published: October 2003

We construct a locally supersymmetric action for the scalar particle, and study its relation with the usual reparametrization invariant action. The mechanisms at work are similar to those employed in the embedding of the bosonic string into the fermionic one, originally due to Berkovits and Vafa in their search for a universal string. The simpler algebraic structure present in the particle case provides us with a guide on how to prove in a simple way, without the need of fixing the superconformal gauge, that the supersymmetric formulation of the bosonic string is equivalent to the usual one, where reparametrization invariance is the only worldsheet gauge symmetry.
Fundamental Strings and D-Strings in the IIB Matrix Model
Authors: Sathiapalan B.
Published: October 2003

The matrix model for IIB superstring proposed by Ishibashi, Kawai, Kitazawa and Tsuchiya is investigated. Consideration of planar and non-planar diagrams suggests that large-N perturbative expansion is consistent with the double scaling limit proposed by the above authors. We write down a Wilson loop that can be interpreted as a fundamental string vertex operator. The one-point tadpole in the presence of a D-string has the right form and this can be viewed as a matrix model derivation of the boundary conditions that define a D-string. We also argue that if worldsheet coordinates σ and τ are introduced to the fundamental string, then the conjugate variable d/dσ and d/dτ can be interpreted as the D-string worldsheet coordinates. In this way the SL (2Z) duality group of the IIB superstring becomes identified with the symplectic group acting on (p,q).
Representations of q-Commutator and Eigenstates of aq in the Case of qs+1=1
Authors: Yang Yaping , Feng Weiguo , Wu Xiang
Published: October 2003

We discuss representations of q-commutator in the case qs+1=1 and some of the applications in mathematical physics, and the eigenstates of annihilation operator have been constructed by means of the generalized Grassmann variables.
Oscillator Quantum Algebra and Deformed su(2) Algebra
Authors: Kubo Harunobu
Published: October 2003

A difference operator realization of quantum deformed oscillator algebra ℋq(1) with a Casimir operator freedom is introduced. We show that this ℋq(1) has a nonlinear mapping to the deformed quantum su(2) which was introduced by Fujikawa et al. We also examine the cyclic representation obtained by this difference operator realization and the possibility to analyze a Bloch electron problem by ℋq(1).
Exact Four-Dimensional Exploding Universe Solution in String Theory
Authors: Nojiri Shin'ichi
Published: October 2003

We obtain a four-dimensional exploding universe solution in string theory. The solution is obtained from the string theory in the flat background by using non-Abelian T-duality and the analytic continuation. In the solution, the radius of the universe is finite for fixed time and the universe is surrounded by the boundary consists of singularity. The boundary runs away with the speed of light and the flat space–time is left behind.
Fusion Rules for Quantum Transfer Matrices as a Dynamical System on Grassmann Manifolds
Authors: Lipan O. , Wiegmann P. B. , Zabrodin A.
Published: October 2003

We show that the set of transfer matrices of an arbitrary fusion type for an integrable quantum model obeys these bilinear functional relations, which are identified with an integrable dynamical system on a Grassmann manifold (higher Hirota equation). The bilinear relations were previously known for a particular class of transfer matrices corresponding to rectangular Young diagrams. We extend this result for general Young diagrams. A general solution of the bilinear equations is presented.
Excess Jet Production at Large ET and Fixed Point QCD
Authors: Leader Elliot , Stamenov Dimiter B.
Published: October 2003

We argue that the apparent discrepancy between conventional QCD and the CDF inclusive jet production data might be an indication that the Callan–Symanzik β-function in QCD corresponds to it has an ultraviolet finite fixed point.
Quantum Mechanical Embedding of Spinning Particle and Induced Spin-Connection
Authors: Ogawa Naohisa
Published: October 2003

This letter introduces the method of the embedding of spinning particle quantum mechanically for nonrelativistic case. Schrödinger equation on its submanifold obtains the gauge field as spin-connection, and it reduces to the connection obtained by Ohnuki and Kitakado when we consider S2 in R3.
Exactly and Quasi-Exactly Solvable Models on the Basis of OSP(2|1)
Authors: Shafiekhani A. , Khorrami M.
Published: October 2003

The exactly and quasi-exactly solvable problems for spin one-half in one dimension on the basis of a hidden dynamical symmetry algebra of Hamiltonian are discussed. We take the supergroup, OSP(2|1), as such a symmetry. A number of exactly solvable examples are considered and their spectrum are evaluated explicitly. Also, a class of quasi-exactly solvable problems on the basis of such a symmetry has been obtained.
Structure of 294,302120 Nuclei Using the Relativistic Mean-Field Method
Authors: Gupta Raj K. , Patra S. K. , Greiner W.
Published: October 2003

We have studied the structure of superheavy nuclei 294,302120 in the framework of a relativistic mean-field formalism, using three different parameter sets (NL1, NL–SH and TM1) in an axially deformed harmonic oscillator basis. The calculated shapes are found to be parameter-dependent, e.g. NL1 parameter set predicts 302120 as a spherical and 294120 a very weakly oblate deformed nucleus whereas NL–SH and TM1 parameter sets predict both the nuclei with strongly prolate/oblate deformed configurations, in their respective ground states. This result, coupled with the calculated single-particle energy spectrum for NL1 parameter set, supports for Z=120 nuclei the spherical magic shell more at N=184 than at N=172. Even for the spherical 302120 nucleus, many new closed shells are predicted and some of the known magic numbers are found absent. Also, the binding energies of the various isotopes of Z=104–111 nuclei are calculated whose comparisons with experimental data favor the NL1 parameter set.
Decay Modes of 180–194Hg Nuclei — A New Possibility of Deformed Daughter Radioactivity
Authors: Gupta Raj K. , Bir Dharm , Dhaulta Sharda
Published: October 2003

Cluster decays of both the normal deformed and superdeformed mercury nuclei ranging from 180 Hg to 194 Hg are studied. It is shown that they are all α-emitters, the superdeformed parents being poorer α-emitters. Also, though almost all the superdeformed 190–194 Hg nuclei are stable against all the heavier clusters, the normal deformed 180–188 Hg nuclei present measurable instabilities against 8 Be and 12 C clusters. The 8 Be and 12 C decays of 180 Hg with T1/2 ~ 1023–1028 s offer as best cases for measurements with the present-day experimental facilities. More significant decays are [Formula: see text] and [Formula: see text], and perhaps also [Formula: see text], which all exhibit shell structure effects and hence predict deformed shell closures at Z=76 or 74 and N=100–104 referring to daughter nuclei. The very stable nature of superdeformed 190–194 Hg parents stresses the presence of (spherical) shell closures at N=110–114 and the very unstable nature of normal deformed 188 Hg parent suggests no (spherical/deformed) shell closure at N=108.
Infrared Finite Charge Propagation
Authors: Bagan Emili , Fiol Bartomeu , Lavelle Martin , McMullan David
Published: October 2003

The Coulomb gauge has a long history and many uses. It is especially useful in bound state applications. An important feature of this gauge is that the matter fields have an infrared finite propagator in an on-shell renormalisation scheme. This is, however, only the case if the renormalisation point is chosen to be the static point on the mass-shell, p=(m,0,0,0). In this letter we show how to extend this key property of the Coulomb gauge to an arbitrary relativistic renormalisation point. This is achieved through the introduction of a new class of gauges of which the Coulomb gauge is a limiting case. A physical explanation for this result is given.
Bound on V+A Admixture in the b→c Current from Inclusive vs Exclusive Semileptonic Decays of B Mesons
Authors: Voloshin M. B.
Published: October 2003

An admixture of a right-handed b→ c current in the semileptonic weak decays of the B mesons would give a significantly different contribution to the inclusive rate of the decays B→lν Xc as compared to the exclusive decay B→ D* lν at zero recoil. Thus a difference in the values of |Vcb| extracted from the data on these two types of decay would measure such admixture. The present marginal mismatch in determination of |Vcb| by the two methods can be interpreted as corresponding to gR/gL≈ 0.14±0.18.
Pontecorvo Neutrino–Antineutrino Oscillations: Theory and Experimental Limits
Authors: Esposito Salvatore , Tancredi Nicola
Published: October 2003

We study Pontecorvo neutrino–antineutrino oscillations both in vacuum and in matter within a field theoretic approach, showing that this phenomenon can occur only if neutrinos have a Dirac–Majorana mass term. We find that matter effects suppress these oscillations and cannot explain the solar neutrino problem. On the contrary, a vacuum neutrino–antineutrino oscillations solution to this problem exists. We analyze this solution and the available data from laboratory experiments giving stringent limits on νe and νμ Majorana masses.
New Exact Vacuum Solutions in Brans–Dicke Theory
Authors: Pimentel Luis O.
Published: October 2003

A family of exact solutions to vacuum Brans–Dicke theory with spherical symmetry is found. In the limit of large ω this family reduces to the solutions obtained in general relativity with a scalar field. The solutions show curvature singularities for all times, therefore they do not represent the gravitational collapse of a physical system with regular initial data in the theory. One would like to interpret it as an inhomogeneous dynamical cosmology, but the lack of a regular spacelike slice forbids it. For a special value of an integration constant we have an isotropic cosmological model without the problems mentioned above.
Condensation and Magnetization of Charged Vector Boson Gas
Authors: Khalilov V. R. , Ho Choon-Lin , Yang Chi
Published: October 2003

The magnetic properties of charged vector boson gas are studied in the very weak, and very strong (near critical value) external magnetic field limits. When the density of the vector boson gas is low, or when the external field is strong, no true Bose–Einstein condensation occurs, though significant amount of bosons will accumulate in the ground state. The gas is ferromagnetic in nature at low temperature. However, Bose–Einstein condensation of vector bosons (scalar bosons as well) is likely to occur in the presence of a uniform weak magnetic field when the gas density is sufficiently high. A transitional density depending on the magnetic field seems to exist below which the vector boson gas changes its property with respect to the Bose–Einstein condensation in a uniform magnetic field.
Extended Vacuum Solutions and their Elementary Excitations of the Yang–Mills Gauge Theory
Authors: Tajima T. , Niu Q.
Published: October 2003

A number of nontrivial vacua of the Yang–Mills gauge theory which are extended in space are derived. For the vacuum solution with a constant "magnetic" field of one color species, the elementary excitations of the other species are circularly polarized, with a spectrum much like the Landau levels of nonrelativistic electrons in a constant magnetic field.
Campbell's Embedding Theorem
Authors: Lidsey James E. , Tavakol Reza , Romero Carlos
Published: October 2003

A little known embedding theorem due to Campbell1 is discussed and employed to establish the local embedding of four-dimensional gravitational and electromagnetic plane waves in five-dimensional Ricci-flat spaces. In general, this theorem can be employed as a way of relating n-dimensional gravity to (n+1)-dimensional vacuum theories.
A Note on the Thermodynamic Properties of a Scalar Field in a Rotating Space–Time
Authors: Radu Eugen
Published: October 2003

We calculate the energy and the entropy of a scalar field in a Gödel-type homogeneous rotating space–time. In the WKB approximation the results do not depend on the magnitude of cosmic rotation.
Large Quantum Gravity Effects: Backreaction on Matter
Authors: Gambini Rodolfo , Pullin Jorge
Published: October 2003

We re-examine the large quantum gravity effects discovered by Ashtekar in the context of (2+1)-dimensional gravity coupled to matter. We study an alternative one-parameter family of coherent states of the theory in which the large quantum gravity effects on the metric can be diminished, at the expense of losing coherence in the matter sector. Which set of states is the one that occurs in nature will determine if the large quantum gravity effects are actually observable as wild fluctuations of the metric or rapid loss of coherence of matter fields.
Classical Integrability of Chiral QCD2 and Classical Curves
Authors: De Mello Koch Robert , Rodrigues João P.
Published: October 2003

In this letter, classical chiral QCD 2 is studied in the lightcone gauge A-=0. The once integrated equation of motion for the current is shown to be of the Lax form, which demonstrates an infinite number of conserved quantities. Specializing to gauge group SU(2), we show that solutions to the classical equations of motion can be identified with a very large class of curves. We demonstrate this correspondence explicitly for two solutions. The classical fermionic fields associated with these currents are then obtained. Finally, we conclude by showing how 't Hooft's large-N solution is obtained from one of our solutions.
BRST Cohomology of the Superstring in Super-Beltrami Parametrization
Authors: Tătaru Liviu , Vancea Ion V.
Published: October 2003

A method for calculating the BRST cohomology, recently developed for 2-D gravity theory and the bosonic string in Beltrami parametrization, is generalized to the superstring theories quantized in super-Beltrami parametrization.
Chiral Phase Transitions in Strong Background Fields at Finite Temperature and Dimensional Reduction
Authors: Ebert D. , Zhukovsky V. Ch.
Published: October 2003

Dynamical fermion mass generation in homogeneous background fields is considered at nonzero temperature. The general features of dynamical chiral symmetry breaking (DχSB) are investigated for several field configurations in relation to their symmetry properties and the form of the fermion spectrum. According to the fields, there arises dimensional reduction by one or two units. In all cases there exists DχSB even at weak fermion attraction, confirming the idea about the dimensional insensitivity of this mechanism in a homogeneous background field.
Zero Curvature Formalism for Supersymmetric Integrable Hierarchies in Superspace
Authors: Aratyn H. , Rasinariu C. , Das A.
Published: October 2003

We generalize the Drinfeld–Sokolov formalism of bosonic integrable hierarchies to superspace, in a way which systematically leads to the zero curvature formulation for the supersymmetric integrable systems starting from the Lax equation in superspace. We use the method of symmetric space as well as the non-Abelian gauge technique to obtain the supersymmetric integrable hierarchies of the AKNS type from the zero curvature condition in superspace with the graded algebras, sl (n+1,n), providing the Hermitian symmetric space structure.
Zeta-Function Regularization and Scale and Conformal Anomalies for the Landau Problem
Authors: Kamath S. G.
Published: October 2003

The technique of ζ-function regularization is used to calculate the anomalies associated with the transformations (t→ e-ρt) and (1/t → 1/t - a) for the Landau Lagrangian. The proper-time transformation function Kij(t,τ;t′,0) now needs to be evaluated exactly, thereby leading to an exact ζ(s,t) for the Landau problem. As a generalization, the calculation when extended to the non-relativistic |ϕ|4 theory in 2+1 dimensions leads to difficulties. We shall discuss some of the difficulties in detail.
U(1) Lattice Gauge Theory and N=2 Supersymmetric Yang–Mills Theory
Authors: Ambjørn Jan , Sasakura Naoki , Espriu Domènec
Published: October 2003

We discuss the physics of four-dimensional compact U(1) lattice gauge theory from the point of view of softly broken N=2 supersymmetric SU(2) Yang–Mills theory. We provide arguments in favor of (pseudo-)critical mass exponents 1/3, 5/11 and 1/2, in agreement with the values observed in the computer simulations. We also show that the J CP assignment of some of the lowest lying states can be naturally explained.
Thermodynamic Basis for the Constancy of the Speed of Light
Authors: Williams Pharis E.
Published: October 2003

It is shown that the laws of thermodynamics require the Einstein postulate on the constancy of the speed of light.
Unusual Behavior in $\bar{p}-p$ and ℓ–p Collisions Involving High Energy and Momentum Transfer: Z0(W±) and Scalar Jets
Authors: Barshay Saul , Kreyerhoff Georg
Published: October 2003

We show that the axial-vector coupling of Z0(W±) to quarks, when acting together with the emission of a hypothetical spin-zero jet-generating quantum coupled to quarks results in an unusual behavior in certain processes, at high energy and momentum transfer. This involves an excess jet production at the subpicobarn level.
M-Theory from Worldsheet Defects in Liouville String
Authors: Ellis John , Mavromatos N. E. , Nanopoulos D. V.
Published: October 2003

We have argued previously that black holes may be represented in a D-brane approach by monopole and vortex defects in a sine–Gordon field theory model of Liouville dynamics on the worldsheet. Supersymmetrizing this sine–Gordon system, we find critical behavior in 11 dimensions, due to defect condensation which we interpret as the worldsheet analog of D-brane condensation around an extra space–time dimension in M-theory. This supersymmetric description of Liouville dynamics has a natural embedding within a 12-dimensional framework suggestive of F-theory.
Quaternionic Mass Matrices and CP-Symmetry
Authors: Lim C. S.
Published: October 2003

A viable formulation of gauge theory with extra generations in terms of quaternionic fields is presented. For the theory to be acceptable, the number of generations should be ≥ 4. The quark–lepton mass matrices are generalized into quaternionic matrices. It is concluded that explicit CP-violation automatically disappears in both strong- and weak-interaction sectors.
Inclusive and Exclusive Decay of B- Meson
Authors: Routh H. , Gautam V. P.
Published: October 2003

In our letter we deal with the inclusive and exclusive decay of B- meson. The inclusive b→dγ decay has been considered here including the QCD corrections to the Wilson coefficients and the matrix elements of the operators in the effective Hamiltonian. We calculate the O(αs) virtual corrections to the matrix element for b→dγ, taking into account the contributions of the four-fermion operator O2 and the electromagnetic and color dipole type operators. It drastically reduces the large scale dependence of the leading logarithmic approximation. Moreover, while we are considering the exclusive B-→ρ-γ decay, we have taken into consideration both the short distance as well as long distance contributions. Therefore, we have obtained better result for the partial decay width of B-→ρ-γ.
A New Redshift Interpretation
Authors: Gentry Robert V.
Published: October 2003

A nonhomogeneous universe with vacuum energy, but without space–time expansion, is utilized together with gravitational and Doppler redshifts as the basis for proposing a new interpretation of the Hubble relation and the 2.7 K Cosmic Blackbody Radiation.
A Covariant Action for the 11-Dimensional Superstring
Authors: Deriglazov A. A. , Galajinsky A. V.
Published: October 2003

We suggest a super-Poincaré invariant action for closed 11-dimensional superstring. The sector of physical variables xi, θa, [Formula: see text], with [Formula: see text],…,8 and xi the transverse part of the D=11 xμ coordinate is shown to possess free dynamics.
Can Extremal Black Holes have Nonzero Entropy?
Authors: Das Saurya , Dasgupta Arundhati , Ramadevi P.
Published: October 2003

We give several pieces of evidence to show that extremal black holes cannot be obtained as limits of non-extremal black holes. We review arguments in the literature showing that the entropy of extremal black holes is zero, while that of near-extremal ones obey the Bekenstein–Hawking formula. However, from the counting of degeneracy of quantum (BPS) states of string theory the entropy of extremal stringy black holes obeys the area law. An attempt is made to reconcile these arguments.
A Proposal of New Gravitational Experiments
Authors: Argyris John , Ciubotariu Corneliu
Published: October 2003

Since "evidently the construction of a laboratory generator of gravitational radiation is an unattractive enterprise in the absence of new engineering or a new idea or both" [C. W. Misner, K. S. Thorne and J. A. Wheeler, Gravitation (Freeman, 1973), p. 979], we propose in this letter some new experiments on the physics of gravitation. These experiments refer to: simulation of accelerations produced by a gravity wave, a source of high-frequency gravitational waves, a direct current gravitational machine, materials with high gravitomagnetic permeability, and finally the possibility of an attenuation of the gravitational attraction. The new ideas involve essentially first the concept of a detector or a source of gravitational radiation in the form of a body in which the motions of particles are precisely the same as those induced by a real gravitational wave in that body, and second, to design a detector having two principal components placed at a distance of λ/2 along the direction of propagation of a gravity wave. We define a new type of gravitomagnetic field generated directly by the time-dependent tidal accelerations of the gravitational wave, and we also define a new concept: the gravitational superconductor.
Doubly Charged Higgsinos and the EDM of the Electron
Authors: Frank M.
Published: October 2003

We study the contribution of the doubly charged higgsino to the electric dipole moment of the electron in a left–right extension of the standard supersymmetric model. The CP violation comes from the trilinear scalar interaction terms in the selectron mixing matrix. We find that this contribution can be quite large, of the same order of magnitude as the electric dipole moment of the electron in the MSSM, and reachable by future experiments.
Possible Excess in Charged Current Events with High-Q2 at HERA from Stop and Sbottom Production
Authors: Kon Tadashi , Matsushita Takashi , Kobayashi Tetsuro
Published: October 2003

We investigate a production process [Formula: see text] at HERA, where we consider a decay mode [Formula: see text] of the sbottom in the framework of an R-parity breaking supersymmetric standard model. Both processes of the stop production [Formula: see text] and the sbottom decay [Formula: see text] are originated from an R-parity breaking superpotential [Formula: see text]. One of the signatures of the process should be a large missing transverse momentum plus multijet events corresponding to hadronic decays of the W. It is shown that the signal could appear as an event excess in the charged current (CC) processes e+p→ν X with the high Q2 at HERA. We compare the expected event distributions with the CC data recently reported by the H1 and ZEUS groups at HERA. Methods for extracting the signal from the standard CC processes are also discussed.
Bc Meson Spectrum and Hyperfine Splittings in the Shifted Large-N-Expansion Technique
Authors: Ikhdair Sameer M. , Sever Ramazan
Published: October 2003

In the framework of potential models for heavy quarkonium, we compute the mass spectrum of the bottom-charmed Bc meson system and spin-dependent splittings from the Schrödinger equation using the shifted-large-N expansion technique. The masses of the lightest vector [Formula: see text] and pseudoscalar Bc states as well as the higher states below the threshold are estimated. Our predicted result for the ground state energy is [Formula: see text] MeV and are generally in exact agreement with earlier calculations. Calculations of the Schrödinger energy eigenvalues are carried out up to the third order of the energy series. The parameters of each potential are adjusted to obtain best agreement with the experimental spin-averaged data (SAD). Our findings are compared with the observed data and with the numerical results obtained by other numerical methods.
Constructing Time Machines
Authors: Shore G. M.
Published: October 2003

The existence of time machines, understood as space–time constructions exhibiting physically realised closed timelike curves (CTC's), would raise fundamental problems with causality and challenge our current understanding of classical and quantum theories of gravity. In this paper, we investigate three proposals for time machines which share some common features: cosmic strings in relative motion, where the conical space–time appears to allow CTC's; colliding gravitational shock waves, which in Aichelburg–Sexl coordinates imply discontinuous geodesics; and the superluminal propagation of light in gravitational radiation metrics in a modified electrodynamics featuring violations of the strong equivalence principle. While we show that ultimately none of these constructions creates a working time machine, their study illustrates the subtle levels at which causal self-consistency imposes itself, and we consider what intuition can be drawn from these examples for future theories.
Casimir Effect in Domain Wall Formation
Authors: Setare M. R.
Published: October 2003

The Casimir forces on two parallel plates in conformally flat de Sitter background due to conformally coupled massless scalar field satisfying mixed boundary conditions on the plates is investigated. In the general case of mixed boundary conditions formulae are derived for the vacuum expectation values of the energy–momentum tensor and vacuum forces acting on boundaries. Different cosmological constants are assumed for the space between and outside of the plates to have general results applicable to the case of domain wall formations in the early universe.
Quasisupersymmetric Solitons of Coupled Scalar Fields in Two Dimensions
Authors: Onizawa S.
Published: October 2003

We consider solitonic solutions of coupled scalar systems, whose Lagrangian has a potential term (quasisupersymmetric potential) consisting of the square of derivative of a superpotential. The most important feature of such a theory is that among soliton masses there holds a Ritz-like combination rule (e.g. M12+M23=M13), instead of the inequality (M12+M23<M13) which is a stability relation generally seen in N=2 supersymmetric theory. The promotion from N=1 to N=2 theory is considered.
Spectral Decomposition and Baxterization of Exotic Bialgebras and Associated Noncommutative Geometries
Authors: Arnaudon D. , Chakrabarti A. , Dobrev V. K. , Mihov S. G.
Published: October 2003

We study the geometric aspects of two exotic bialgebras S03 and S14 introduced in math.QA/0206053. These bialgebras are obtained by the Faddeev–Reshetikhin–Takhtajan RTT prescription with non-triangular R-matrices which are denoted R03 and R14 in the classification of Hietarinta, and they are not deformations of either GL(2) or GL(1|1). We give the spectral decomposition which involves two, respectively, three, projectors. These projectors are then used to provide the baxterization procedure with one, respectively, two, parameters. Further, the projectors are used to construct the noncommutative planes together with the corresponding differentials following the Wess–Zumino prescription. In all these constructions there appear nonstandard features which are noted. Such features show the importance of systematic study of all bialgebras of four generators.
On the Gravitational Energy of the Hawking Wormhole
Authors: Culetu H.
Published: October 2003

The surface energy for a conformally flat space–time which represents the Hawking wormhole in spherical (static) Rindler coordinates is computed using the Hawking–Hunter formalism for nonasymptotically flat space–times. The physical gravitational Hamiltonian is proportional to the Rindler acceleration g of the hyperbolic observer and is finite on the event horizon ξ=b (b — the Planck length, ξ — the Minkowski interval). The corresponding temperature of the system of particles associated to the massless scalar field Ψ=1-b2/ξ2, coupled conformally to Einstein's equations, is given by the Davies–Unruh temperature up to a constant factor of order unity.
Engineering a Bosonic AdS/CFT Correspondence
Authors: Ketov Sergei V. , Leonhardt Thorsten , Rühl Werner
Published: October 2003

We search for a bosonic (nonsupersymmetric) string/gauge theory correspondence by using the ten-dimensional IIB and 0B strings as a guide. Our construction is based on the low-energy bosonic string effective action modified by an extra form flux. We prove that the closed string tachyon can be stabilized in this context, when the AdS scalem L does not exceed a certain critical value, L<L c . The extra form may be nonperturbatively generated as a soliton from 3-string junctions, similarly to the known nonperturbative (Jackiw–Rebbi–'t Hooft–Hasenfratz) mechanism in gauge theories, as was recently argued by David, Minwalla and Núñez. We find a stable AdS 13×S13 solution that implies the existence of a 12-dimensional AdS-boundary conformal field theory with the SO(14) global symmetry in the large N't Hooft limit, which is similar to the recently proposed bosonic M-theory of Horowitz and Susskind. Taking the proposed bosonic AdS/CFT correspondence for granted, we generalize it to finite temperature. The corresponding "glueball" masses in higher space–time dimensions are calculated from the dilaton wave equation in the AdS black hole background.
Cryptographic Unification of Mass and Space Links Neutrino Flavor (νe/νμ) Transformations with the Cosmological Constant Λ
Authors: Dai Yang , Borisov Alex B. , Longworth James W. , Boyer Keith , Rhodes Charles K.
Published: October 2003

The universe exhibits two striking manifestations, (a) immense complexity and (b) an astonishingly high scale-free precision. Since a cryptographic system based on the modular arithmetic of a finite field can provide a mathematical structure matching these two cardinal characteristics, it is natural to evaluate the theoretical possibilities of a cryptographic analysis of physical phenomena. The organization of the particle mass scale provides a particularly suitable test of this idea, since the cryptographic approach also has the inherent feature that divergences are fully barred, thereby eliminating the need for ad hoc procedures of renormalization. This article (1) shows how such a cryptographic concept can be implemented and (2) demonstrates its surprising ability to synthesize the description of a broad range of phenomena through the development of an interlocking set of quantitative findings. It is found that a cryptographic theoretical framework based solely on two physically anchored parameters, a modulus Pαand a corresponding primitive root gα, can simultaneously achieve six goals. Specifically, it (α) unites the concepts of mass and space, (β) organizes the physical mass scale in a group structure, (γ) produces a quantitative concordance of findings linking the cosmic and micro-scales that includes values for the fine structure constant α and the unified strong-electroweak coupling constant α*, (δ) respectively gives prospective magnitudes of 0.808 meV and 27.68 meV for the rest masses mνeand mνμof the electron (νe) and muon (νμ) neutrinos, (∊) specifies a symmetry condition that yields an exact predicted value for the Higgs particle mass that lies above 1018GeV, and (ζ) enables the formulation of a direct physical connection between the anomalous flavor (νe/νμ) transforming propagation of solar neutrinos and the existence of a positive cosmological constant Λ. These results are uniformly in agreement with all corresponding observational data.
Structure and Optical Properties of Nanocrystalline Yttria Doped Ceria Thin Films
Authors: Hartridge A. , Krishna M. Ghanashyam , Bhattacharya A. K.
Published: October 2003

Thin films of Ce 1-x Y x O 2-y where x ranges from 0 to 0.5 have been coated onto glass substrates using an inorganic sol–gel approach at low temperature. The lattice parameters from powder diffraction measurements were calculated and shown to be very close to those previously reported. Crystallite size measurements indicated that the films were nanocrystalline, the size decreasing as a function of dopant concentration. The films are transparent in the region 500 to 1500 nm with very low optical losses. The film refractive index is dependent on the dopant concentration and peaks at an yttria concentration of x=0.25 after treatment at 450° C , with a value of 1.79, which on increasing the yttria concentration to x=0.50 decreases to 1.65 in the dispersion free region. The optical band gap is also dependent on the dopant concentration and is in the range 3.2 to 3.0 eV.
Nonlinear Field Theoretical Approaches to the Electron Density Amplitude Equation in Many-Electron Atoms and Molecules
Authors: Dixon J. M. , Tuszyński J. A. , March N. H.
Published: October 2003

In this paper we have presented a comparison of the effective one-body potentials arising in Thomas–Fermi (TF) phenomenology and density function (DF) theories on the one hand and the Method of Coherent Structures (MCS) on the other. In spite of a number of assumptions made in TF and DF, particularly in connection with the exchange component of the potential, quantitative agreement has been found with the MCS. In addition we have drawn attention to several similarities in the associated energy functionals. The Saxon–Woods potential, used in diverse contexts of many-body physics, has been shown to satisfy a nonlinear differential equation which can be transformed into a equation of the class satisfied by the classical field equation in the MCS. This indicates, once more, that there are intricate connections between phenomenological approaches, which attempt to incorporate many-body physical effects, and the systematic and unifying development offered within the MCS.
Electronic Transmittance and Localisation in Quasi-1D Systems of Coupled Identical n-Mer Chains
Authors: Mitra Tapas , Thakur Prabhat K.
Published: October 2003

The effect of interchain coupling on the electronic transmittance of Quasi-1D systems consisting of identical chains containing impurities in the form of blocks of n identical impurity atoms. The regions where transmittance was nearly unity for a single chain are now modified by fluctuations and different metallic regions may merge together.
Impurity-Induced Magnetic Anomalies in the Slightly Diluted Low Anisotropy A2Fe1-xInxCl5·H2O, (A=K, Rb) Antiferromagnets: An Overview
Authors: Palacio Fernando , Campo Javier , Carmen Morón M. , Paduan-Filho Armando , Becerra Carlos C.
Published: October 2003

The phase diagram of low anisotropy antiferromagnets contains regions where small perturbations in the structure can induce rich interesting physical phenomenology that is still to be fully understood. This paper reviews the anomalies observed in site-diluted antiferromagnets in two regions of the magnetic phase diagram: the region where the magnetic field is very low, normally less than 10 Oe, and the spin-flop region. Although the observed phenomena is quite general, the magnetic behavior of the solid solutions A 2 Fe 1-x In x Cl 5· H 2 O , (A=K, Rb) is used to exemplify such anomalies.
Bilayered Spin-S Heisenberg Model in Fractional Dimensions
Authors: Ng K. K.
Published: October 2003

The ground state and the phase transitions of the bilayered spin-S anti-ferromagnetic Heisenberg model were studied by Ng et al.1 by using the Schwinger boson mean field theory. In this paper, an analytic continuation of the self-consistent equations is carried out in order to study the extension of the model to fractional dimensions from 1 to 2. Decreasing the dimensionality from 2 has an effect similar to that of decreasing the spin S. The corresponding phase diagram and phase transition will also be discussed.
Multicritical Points from Mean Field Renormalization Group
Authors: Peña Lara D. , Plascak J. A. , Ricardo de Souza J.
Published: October 2003

The mean field renormalization group method is extended to study tri-critical phenomena. By taking into account the third-order terms in the expansion of the magnetizations of the different clusters with respect to the symmetry breaking fields, together with the scaling assumption of the magnetization at a first-order fixed point, one additional equation is obtained which locates, in an unique manner, the tricritical point. This approach is applied in the study of the classical spin-σ Blume–Capel model and the quantum spin-1/2 anisotropic Heisenberg model in the presence of a transverse field as well as with Dzyaloshinsky–Moriya interactions.
Micro-Raman Scattering Properties of Highly Oriented AlN Films
Authors: Liu Ming S. , Nugent K. W. , Prawer S. , Bursill L. A. , Peng J. L. , Tong Y. Z. , Jewsbury P.
Published: October 2003

Micro-Raman scattering by highly oriented crystalline aluminum nitride has been measured. Phonon modes in AlN were identified in different scattering geometry configurations and scattering polarizations. The phonon modes revealed that aluminum nitride films are highly oriented with the wurtzite c-axis direction normal to the film plane. The Raman scattering modes are broadened and shifted due to grain boundaries and other defects in the films. The defect scattering was analysed using the phonon confinement model. These results were compared with results obtained from X-ray diffraction powder patterns and high-resolution transmission electron microscopy.
The Critical Behavior of the General Spin Blume–Capel Model
Authors: Lara D. Peña , Plascak J. A.
Published: October 2003

The general spin-S Blume–Capel model is studied within two different approaches: the pair approximation for the free energy, and Monte Carlo simulations. The global phase diagram in the temperature-anisotropy plane is obtained for general values of S in the pair approximation and the results are qualitatively the same as those of the usual mean field theory. Special interest is given in the low temperature region of the phase diagram where a number of first-order lines emerge from a multiphase point at the ground state. Monte Carlo simulations for S=1, 3/2, and 2 on simple cubic lattices also confirm the general trend of the mean field like approach, and in the special S=3/2 case the present results are in disagreement with previous Monte Carlo simulations, as well as renormalization group calculations on corresponding two-dimensional lattices.
Vibrational and Magnetic Contribution to Entropy of an L12 Ordered and a Partially Ordered Ni3Mn Alloy: Results from Thermal Expansion Measurements and Model Calculations
Authors: Mukherjee Goutam Dev , Bansal C. , Chatterjee Ashok
Published: October 2003

Thermal expansion measurements have been performed on an L12 ordered and a quenched Ni3Mn alloy and the role of electrons, phonons and magnetic moments on their thermodynamic properties has been studied using theoretical models. We show that with increasing atomic disorder the itinerant nature of the electron moments decreases. We furthermore show that magnetic interactions do not influence the chemical ordering of Ni3Mn , while lattice vibrations play an important role in its ordering transition.