Photon Decays in the Radiation-Dominated Universe: Scalar Electrodynamics

The effect of the creation of an arbitrary number of massive pairs by a photon in the spatially flat model of the radiation-dominated Universe is considered. The process added-up probability is calculated within the framework of scalar quantum electrodynamics conformally related to the metric of a curved spacetime. The rate of photon decay in the radiation-dominated universe as well as the mean number of the created particles have been found. Comparison of the rate of the pair creation in the photon decays with the rate of the pair creation in the photon-photon collisions which take place in the Minkowski spacetime has been carried out. The estimates having been made show the number density of the particles created in the processes of the photon decays in the radiation-dominated Universe to be by a factor of 10³⁰ higher than the number density of the particles created from the vacuum of the free scalar field by the gravitational background.     

The Scalar Photon Light-Cone Distribution Amplitude in the Instanton Vacuum Model of QCD

Based on the principle of the Lorentz covariance, the transition matrix elements from an off-shell photon state to the vacuum are parameterized by the light-cone photon distribution amplitudes （DAs）. Both the scalar off-shell photon light-cone DA and the corresponding coupling are calculated in the instanton vacuum model of quantum chromodynamics （QCD）, and their explicit analytical expressions and the numerical results are given. The results for the other chiral-odd light-cone photon DAs and their couplings are presented as well.     

Bound States in the Quantum Scalar Electrodynamics

The next relativistic correction to α to for bound state mass of two charged scalar particles is calculated in the quantum scalar electrodynamics by the functional integral method. Contribution of the “nonphysical” time variable turned out to be important and leads to nonanalytic dependence of the bound state mass on α.     

Nonlocal Scalar Electrodynamics from Chern-Simons Theory

The theory of a complex scalar interacting with a pure Chern-Simons gauge field is quantized canonically. Dynamical and nondynarnical variables are separated in a gaugeindependent way. In the physical subspace of the full Hilbert space, this theory reduces to a pure scalar theory with nonlocal interaction. Several scattering processes are studied and the cross sections are calculated.     

The Elastic Interpretation of Electrodynamics

In his famous treatise, Maxwell presumed explicitly, without developing it, an elastic interpretation of his electrodynamics; the relevant quotation is given in the introduction. It is in that spirit that we have developed the theory of the elastic interpretation here presented. We show that the Maxwell equations and the electrodynamic forces can formally be obtained from the theory of elasticity. An electromagnetic field can be considered as a deformation of a certain elastic medium . This deformation is created by volumetric densities of deforming couples and of irrotational deforming forces that act on . A distribution of electric charges is proportional to the divergence of the deforming couples. The electrodynamic forces are due to the interactions between such deformations. Even though the consistency of the elastic interpretation of electrodynamics is demonstrated by the fact that it gives back Maxwell's equations, and the electrodynamic forces, we show that the elastic interpretation is compatible with Einstein's special relativity. Then we demonstrate that an adequate density of irrotational deforming forces can produce the same effects on light propagation as those of a Schwarzschild metric background. This fact suggests a possible extension to take into account many of the effects attributed to the geometrical structure of the general relativity. Thus, we have given an elastic interpretation to the action at distance, and contributed to eliminate the inconsistency mentioned by Einstein, implying in his view, an incompleteness of the Maxwell theory. In future works, we hope to give an elastic interpretation for additional aspects of the particle waves and of general relativity and for the electroweak and strong fields.     

Minimal Photon Velocity Bounds in Non-relativistic Quantum Electrodynamics

We consider non-relativistic quantum particle systems, such as atoms and molecules, coupled to the quantized electromagnetic field. We prove several photon velocity bounds for total energies below the ionization threshold. We also consider phonons coupled to such particle systems and prove velocity bounds for them as well.     

On Rayleigh Scattering in Non-Relativistic Quantum Electrodynamics

We consider a particle system coupled to the quantized electromagnetic or phonon field. Assuming that the coupling is small enough and that Fermi’s Golden Rule is satisfied, we prove asymptotic completeness for Rayleigh scattering on the states for which the expectation of either the photon/phonon number operator or an operator testing the photon/phonon infrared behaviour is uniformly bounded on corresponding dense sets. By extending a recent result of De Roeck and Kupiainen in a straightforward way, we show that the second of these conditions is satisfied for the spin-boson model.     

Electrodynamics of a Scalar Particle in a Plane Electromagnetic Wave Field

In the present paper, compact expressions are derived for the probability of photon emission by a scalar particle and for the probability of creating pairs of scalar particles in an arbitrary plane electromagnetic wave field. Based on these general expressions, the amplitude of elastic scattering of a scalar particle and the amplitude of elastic scattering of a photon are derived by the method of dispersion relations (in the first-order approximation for the fine-structure constant ₀ = e ²/4). The real components of these amplitudes determine the radiative corrections for particle masses in the examined fields. Some particular cases of the plane wave field are examined. In particular, the above-indicated amplitudes in the external electromagnetic field being a superposition of a constant crossed field and a plane elliptically polarized electromagnetic wave propagating along the direction orthogonal to the magnetic and electric components of the constant crossed field are investigated. The amplitude of elastic scattering of a scalar particle in an arbitrary plane electromagnetic wave field is also obtained by direct calculations of the corresponding mass operator of the scalar particle in this field.     

Higher-Order Kinetic Term for Controlling Photon Mass in Off-Shell Electrodynamics

In relativistic classical and quantum mechanics with Poincaré-invariant parameter, particle worldlines are traced out by the evolution of spacetime events. The formulation of a covariant canonical framework for the evolving events leads to a dynamical theory in which mass conservation is demoted from a priori constraint to the status of conserved Noether current for a certain class of interactions. In pre-Maxwell electrodynamics—the local gauge theory associated with this framework —events induce five local off-shell fields, which mediate interactions between instantaneous events, not between the worldlines which represent entire particle histories. The fifth field, required to compensate for dependence of gauge transformations on the evolution parameter, enables the exchange of mass between particles and fields. In the equilibrium limit, these pre-Maxwell fields are pushed onto the zero-mass shell, but during interactions there is no mechanism regulating the mass that photons may acquire, even when event trajectories evolve far into the spacelike region. This feature of the off-shell formalism requires the application of some ad hoc mechanism for controlling the photon mass in two opposite physical domains: the low energy motion of a charged event in classical Coulomb scattering, and the renormalization of off-shell quantum electrodynamics. In this paper, we discuss a nonlocal, higher derivative correction to the photon kinetic term, which provides regulation of the photon mass in a manner which preserves the gauge invariance and Poincaré covariance of the original theory. We demonstrate that the inclusion of this term is equivalent to an earlier solution to the classical Coulomb problem, and that the resulting quantum field theory is renormalized.     

中能质子与4He原子核弹性散射中N-N振幅的相改变

在KMT多重散射理论框架下，应用动量空间一级光学势，基于Franco和Yin关于核子-核子散射振幅的相随动量转移而改变的建议，研究了入射能量为1GeV时的质子-4He弹性散射. 发现这个相改变使得KMT类型的理论计算的微分散射截面和极化本领与实验符合得更好.     

Scattering and Radiation Damping in Gyroscopic Lorentz Electrodynamics

Relativistic Lorentz electrodynamics (LED) is studied in a gyroscopic setup in which the Lorentz electron is assumed to be unaccelerated, leaving the electromagnetic fields and the particle spin as the only dynamical degrees of freedom. The global existence and uniqueness of this nonlinear gyroscopic spin-plus-field dynamics in unbounded space is proven. It is further shown that for rotation-reflection symmetric initial data any gyroscopic solution also satisfies the world-line equations consistent with a nonmoving Lorentz electron, thus furnishing a proper solution of the complete set of equations of LED. Rotation-reflection symmetric scattering is shown to occur for sufficiently small ratio of electrostatic to (positive) bare rest mass, with deviations from the stationary spin state dying out exponentially fast through radiation damping. The previously proven result that the renormalized spinning Lorentz electron evolves like a soliton in scattering processes combined with the present results that scattering does occur establish the solitonic character of the renormalized Lorentz electron.     

Scalar Quantum Electrodynamics on the lattice as classical statistical mechanics

Wilson's lattice approximation allows us to apply classical statistical mechanics ideas to the study of Scalar Quantum Electrodynamics. Our main tools are Griffiths-Kelly-Sherman inequalities, the transfer matrix formalism and exponential bounds. Our main result is the existence of the infinite volume limit for every value of the coupling parameters.     

Hyperon-Neutron Elastic Scattering

It is shown that the Chou-Yang model can be extended to hyperon-neutron elastic reactions at high energies by assuming that the hadronic form factor of neutron is proportional to its magnetic form factor. It is also predicted that the scaling of magnetic form factor of neutron with charge as well as magnetic form factors of proton implies that the differential cross sections of corresponding hyperon-proton and hyperon-neutron reactions should be equal.     

荷电标量分子对光子与光子散射振幅贡献的精确解析表达式

计算了荷电标量介子的圈图对光子与光子散射的四阶极化张量和圆极化散射振幅的贡献，得到了它们依赖于三个超越函数Ｂ（ｕ），Ｔ（ｕ）和Ｉ（ｕ，ｖ）的精确解析表达式．     

Polarization Phenomena in Elastic Electron-Proton Scattering

A unified treatment is given by using the scattering matrix in the Pauli spin spaces and polarization density matrices. Various quantities such as polarization P, asymmetry A, spin correlation parameters C_αβ, double polarization asymmetry A_αβ, polarization transfer parameters D_t, A_t, R_t and depolarization and spin rotation parameters D, A, R are expressed in terms of six coefficients which appear in the scattering matrix. Some explicit expressions as well as numerical results for these quantities are also given in the one photon exchange approximation.     

Calculation of Photon Path Distribution Based on Photon Behavior Analysis in a Scattering Medium

We calculated the photon path distribution (PPD) in a scattering medium based on a theoretical analysis, which utilizes the relationship between the photon intensity and photon pathlength. This PPD is defined by local photon pathlengths for photons having total pathlengths of l between the light input points and detection points. The PPD of photons that consist of the impulse response at time t (= l/c) was calculated for a 2-D model. Precise analysis of photon migration in the scattering medium is essential in order to carry out image reconstruction of diffuse optical tomography (DOT). We show the PPD at time t (the total pathlength l = ct) and demonstrate its effectiveness. Our method for describing photon migration is intuitive and allows finding weight functions in DOT.     

Scattering Matrix Modeling of Photon Migration in Turbid Media

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