Fresh Inflation with Nonminimally Coupled Inflaton Field

I study a fresh inflationary model with a scalar field nonminimally coupled to gravity. An example is examined. I find that, as larger is the value of p (a t ^p ), as smaller (but larger in its absolute value) is the necessary value of the coupling to the inflaton field fluctuations can satisfy a scale invariant power spectrum.     

Stability Properties and Asymptotics for N Nonminimally Coupled Scalar Fields Cosmology

We consider here the dynamics of some homogeneous and isotropic cosmological models with N interacting classical scalar fields nonminimally coupled to the spacetime curvature, as an attempt to generalize some recent results obtained for one and two scalar fields. We show that a Lyapunov function can be constructed under certain conditions for a large class of models, suggesting that chaotic behavior is ruled out for them. Typical solutions tend generically to the empty de Sitter (or Minkowski) fixed points, and the previous asymptotic results obtained for the one field model remain valid. In particular, we confirm that, for large times and a vanishing cosmological constant, even in the presence of the extra scalar fields, the universe tends to an infinite diluted matter dominated era.     

Dynamical Study of the Singularities of Gravity in the Presence of Nonminimally Coupled Scalar Fields

We investigate the dynamics of Einstein equations in the vicinity of the two recently described types of singularity of anisotropic and homogeneous cosmological models described by the action

Cosmic Strings Coupled with a Massless Scalar Field

A scalar field generalization of Xanthopoulos's cylindrically symmetric solutions of the vacuum-Einstein equations is obtained. The obtained solution preserves the properties of the Xanthopoulos solution, which are regular on the axis, asymptotically flat, and free from the curvature singularities. The solution describes a stable, rotating cosmic string of infinite length interacting with gravitational and scalar waves.     

Regular Electric Field in Electromagnetic Coupled to a Scalar Field

In the framework of an electromagnetic field coupled nonminimally with a scalar field in flat spacetime, the existence of a non-singular electric field is proved for a point electric charge or electric monopole. In analogy with the Maxwell-dilaton system introduced by Gibbons and Wells, first, a Maxwell-anti-dilaton system is constructed where the radial electric field of a static electric monopole is coupled to an anti-dilaton. The field equations are solved analytically for the electric and dilaton fields and observe the nonsingular electric field. Also, the self-energy of the electric monopole is found to be finite. Furthermore, the formalism to a Maxwell-scalar field is generalized where a mechanism is introduced upon which the coupled regular-electric field and scalar field is obtained. The formalism shows that for a given regular electric field there are two supersymmetric coupling functions corresponding to a scalar and a phantom field.     

Phantom Dilaton Field and Asymptotic Distribution Parameter in (2+1)-Dimensional Maxwell-Chern-Simons Gravity

The (2+1)-dimensional Maxwell-Chern-Simons gravity with phantom dilaton field coupling is studied in this paper.It is shown that black hole solution to exist when electromagnetic coupled to dilaton field in the non-trivial way.Moreover,asymptotic index and distribution parameter of current density are calculated by using black hole solution,some new features of this solution are briefly discussed.     

Abel Chern-Simons项与复标量场耦合系统的正则量子化

应用Faddeev-Jackiw方法对Abel Chern-Simons项与复标量场耦合系统进行正则量子化,它表明用这种方法进行量子化更加直接和优美.     

Effective Dynamics for Particles Coupled to a Quantized Scalar Field

We consider a system of N non-relativistic spinless quantum particles (“electrons”) interacting with a quantized scalar Bose field (whose excitations we call “photons”). We examine the case when the velocity v of the electrons is small with respect to the one of the photons, denoted by c (v/c = ε ≪ 1). We show that dressed particle states exist (particles surrounded by “virtual photons”), which, up to terms of order (v/c)³, follow Hamiltonian dynamics. The effective N-particle Hamiltonian contains the kinetic energies of the particles and Coulomb-like pair potentials at order (v/c)⁰ and the velocity dependent Darwin interaction and a mass renormalization at order (v/c)². Beyond that order the effective dynamics are expected to be dissipative. The main mathematical tool we use is adiabatic perturbation theory. However, in the present case there is no eigenvalue which is separated by a gap from the rest of the spectrum, but its role is taken by the bottom of the absolutely continuous spectrum, which is not an eigenvalue. Nevertheless we construct approximate dressed electron subspaces, which are adiabatically invariant for the dynamics up to order . We also give an explicit expression for the non-adiabatic transitions corresponding to emission of free photons. For the radiated energy we obtain the quantum analogue of the Larmor formula of classical electrodynamics.     

Dynamics of Solitons in Coupled System of Scalar Fields

The dynamics of interacting solitons of a system of two coupled nonlinear partial differential equations is studied numerically using a finite difference method in bi-dimensional spacetime. Stable, static topological solitons are obtained from an iterative-variational method, and used as initial solutions for the dynamical calculations. Some of the static solutions decay to stable solitons. Some subtle aspects of topological charges for the system under consideration are also discussed.     

Novel Localized Excitations of Nonlinear Coupled Scalar Fields

Some extended solution mapping relations of the nonlinear coupled scalar field and the well-known φ^4 model are presented. Simultaneously, inspired by the new solutions of the famous φ^4 model recently proposed by Jia, Huang and Lou, five kinds of new localized excitations of the nonlinear coupled scaiar field （NCSF） system are obtained.     

Ground State of a Quantum Particle Coupled to a Scalar Bose Field

We use methods from functional integration to prove the existence and uniqueness of the ground state of a confined quantum particle coupled to a scalar massless Bose field. For an external potential growing at infinity, the ground state exists under fairly general conditions while, for a decaying potential, an unphysical condition on the coupling strength is still needed.     

The Causal Interpretation of Conformally Coupled Scalar Field Quantum Cosmology

We apply the causal interpretation of quantum mechanics to homogeneous and isotropic quantum cosmology, where the source of the gravitational field is a conformally coupled scalar field, and the maximally symmetric hypersurfaces have positive curvature. In order to simplify the system of coupled equations studied and study the quantum behavior near the singularity, we restricted ourselves to the cases where the scale factor is small. In this case, the general solution of the Wheeler–DeWitt equation is a discrete superposition of Hermitian polynomials multiplied by complex exponentials. Superpositions with up to two parcels are studied, and the phase diagrams of their corresponding Bohmian trajectories are analyzed in detail. Nonsingular periodic quantum solutions are found. We also find that singular quantum solutions present an inflationary era in the begining of the Universe. Numerical calculations indicates that these results remain valid for general superpositions.     

Quasinormal Modes of a Coupled Scalar Field in the Acoustic Black Hole Spacetime

By using the third-order Wentzel-Kramers-Brillouin approximation and the monodromy methods, the quasnormal modes of a coupled scalar field in the canonical non-rotating acoustic black hole spacetime are investigated. It is shown that the coupling between the scalar field and background metric affects the quasinormal frequencies. At low overtones, both the real part and the magnitude of imaginary part increase with the couple factor ξ. For the larger ξ, both of them are almost linearly related to the couple factor. At high overtones, it is found that the frequency formula of the quasinormal modes is 2πω/κ = ln （ 1 ＋ 2 cos√9-24ξ/5 π） - i（2n ＋ 1）π, which means that 5 when ξ is larger, the real part is the linear function of ξ^1/2.     

How Will a Particle Detector Respond in Massless Complex Scalar Field？

I study the response of a particle detector coupled to quantized massless complex scalar field in four dimensional Minkowski spacetime through nonlinear Lagrangian. I find that as in the real scalar field： the particle detector will not respond when it is in inertial motion; If accelerated in its own frame reference, it does respond and feel the same temperature. But different from the real scalar field case, the detector＇s transition amplitude is concerned with particle-antiparticle creation, and the response of the detector is （1/α^2 ＋ ε^2）/24π^2 times of that in real scalar field, with 1/α the accelerator of the detector and e the energy gap between the detector＇s two energy level. It is due to the nonlinear property of the coupling Lagrangian. Whether the total charge of the system constructed by the particle detector and vacuum is conserved is also considered and analyzed.     

Exact Solutions for the Fluctuations in a Flat FRW Universe Coupled to a Scalar Field

Some exact solutions for the small-first-order perturbations of an FRW metric minimally coupled to a neutral massive scalar field are presented.     

Exact Solitary Wave Solutions of the Coupled Nonlinear Scalar Field Equations

Because of the arbitrary property of the singular manifold, the usual singularity analysis can be extended to a different form. Using a nonstandard truncation approach, five special types of exact solution of the coupled nonlinear scalar field equations are obtained.     

Scaling Limits for the System of Semi-Relativistic Particles Coupled to a Scalar Bose Field

In this paper, the Hamiltonian for the system of semi-relativistic particles interacting with a scalar Bose field is investigated. A scaled total Hamiltonian of the system is defined and its scaling limit is considered. Then, a semi-relativistic Schrödinger operator with an effective potential is derived.