Gravitational radiation,radiation damping,and the fast-motion approximation

The sign of the gravitational energy radiated by a material system, as calculated by one or another appropriate stress-energy pseudotensor, is shown always to be positive. A fastmotion approximation that finds this quantity to be negative is shown to violate one of the conditions that ensure its positivity. As a consequence the calculation based on this approximation is shown to neglect terms of the same order (G ²) as it retains.     

Surface-induced valley-splitting in n-channel (001) silicon-MOS charge layer

The surface-induced valley-splitting theory by Sham and Nakayama is shown in the special case of a two-band model for the silicon band structure to be closely related to the electric break-through effect of Ohkawa and Uemura. Recent criticisms of our theory by Ohkawa are shown to be erroneous.     

Friction through dynamical formation and rupture of molecular bonds

We introduce a model for friction in a system of two rigid plates connected by bonds (springs) and experiencing an external drive. The macroscopic frictional properties of the system are shown to be directly related to the rupture and formation dynamics of the microscopic bonds. Different regimes of motion are characterized by different rates of rupture and formation relative to the driving velocity. In particular, the stick-slip regime is shown to correspond to a cooperative rupture of the bonds. Moreover, the notion of static friction is shown to be dependent on the experimental conditions and time scales. The overall behavior can be described in terms of two Deborah numbers.     

Force distortion in resonance testing of structures with electro-dynamic vibration exciters

Harmonic input force distortion which arises when systems are excited with electrodynamic exciters is shown to be predominantly second harmonic, the major source of the harmonic distortion being due to the vibration exciter characteristics. These are examined by experimentally determining the magnetic field strength properties of a typical exciter and the results show these to be a non-linear even function. This information is used with the equations of motion of the excited which are simulated on an analog computer. The computed force characteristics are shown to compare very closely with experimental results. The amount of second harmonic force distortion generated at a system resonance is analyzed by considering a simple single degree-of-freedom model. It is shown that the amount of force distortion is related to the damping of the system under test and the ratio of the exciter stiffness to the system stiffness. It is also shown that the force input to a system near a system resonance can vary considerably, even though the input current to the exciter is constant. These effects are shown to be due to the forces arising from the mass and stiffness characteristics of the exciter being used. Experimental tests on a simple system confirm the theoretical predictions.     

Entropy and Vacuum Radiation

It is shown that entropy increase in thermodynamic systems can plausibly be accounted for by the random action of vacuum radiation. A recent calculation by Rueda using stochastic electrodynamics (SED) shows that vacuum radiation causes a particle to undergo a rapid Brownian motion about its average dynamical trajectory. It is shown that the magnitude of spatial drift calculated by Rueda can also be predicted by assuming that the average magnitudes of random shifts in position and momentum of a particle correspond to the lower limits of the uncertainty relation. The latter analysis yields a plausible expression for the shift in momentum caused by vacuum radiation. It is shown that when the latter shift in momentum is magnified in particle interactions, the fractional change in each momentum component is on the order of unity within a few collision times, for gases and (plausibly) for denser systems over a very broad range of physical conditions. So any system of particles in this broad range of conditions would move to maximum entropy, subject to its thermodynamic constraints, within a few collision times. It is shown that the spatial drift caused by vacuum radiation, as predicted by the above SED calculation, can be macroscopic in some circumstances, and an experimental test of this effect is proposed. Consistency of the above results with quantum mechanics is discussed, and it is shown that the diffusion constant associated with the above Brownian drift is the same as that used in stochastic interpretations of the Schrödinger equation.     

Rotational relativity theory

The constancy of the spin of the photon was recently shown to lead to a new Lorentz-type transformation that relates the energy, rotational velocity, moment of inertia, and angular momentum, where rotational invariance was the basis of the theory instead of the ordinary linear invariance of special relativity. In this paper the new group of transformations is shown to lead naturally to a special theory of relativity whose basic metric has anR×S ³ topology rather than the familiar Minkowskian metric. Predictions by the theory are shown to be highly supported by experiment.     

Harada–Tsutsui gauge recovery procedure: From Abelian gauge anomalies to the Stueckelberg mechanism

Revisiting a path-integral procedure developed by Harada and Tsutsui for recovering gauge invariance from anomalous effective actions, it is shown that there are two ways to achieve gauge symmetry: one already presented by the authors, which is shown to preserve the anomaly in the sense of standard current conservation law, and another one which is anomaly-free, preserving current conservation. It is also shown that the application of the Harada–Tsutsui technique to other models which are not anomalous but do not exhibit gauge invariance allows the identification of the gauge invariant formulation of the Proca model, also done by the referred authors, with the Stueckelberg model, leading to the interpretation of the gauge invariant map as a generalization of the Stueckelberg mechanism.     

Chemistry in Lasers. IX. Reexamination of the Einstein Coefficients and Two Level Population Inversion

From a re-examination of the Einstein coefficients in terms of current theory the common assumption that population inversion cannot be maintained in a two level system by optical pumping is shown to be erroneous. The nonisotropy of the radiative ensemble in an optical resonant cavity, absent from the original derivation by Einstein, is shown to be of decisive importance.     

Reply to comments on “laser excitation of surface electronic states for a one-dimensional semiconductor” by G.W. Bryant

A semiconductor modeled by a finite one-dimensional chain is shown to have either a continuous or discrete number of surface states. The exact number is determined by the choice of phase factors. Laser-induced charge transfer of electrons from the bulk to these surface states is also shown to be a maximum at the band edge.     

Comment on real-time finite-temperature gauge field propagators

The gauge-fixing terms of the free, real-time thermal gauge field propagators corresponding to quantization in a covariant gauge obtained by Kobes, Semenoff, and Weiss are shown to be incorrect, apart from well-known signature ambiguities in the off-diagonal elements, and to differ from those obtained by Landsman using the method of the Klein-Gordon divisor. We obtain the correct forms which are then shown to coincide with Landsman's results by means of a distributional identity.     

Mid-infrared microlenses fabricated by the melting method

It is shown that by using the melting method it is possible to fabricate microlenses that work with mid-IR radiation. The fabrication method is described, and the characteristics of the polymeric material and the fabricated lenses are shown.     

The role of nuclear binding in deep inelastic lepton-nucleon scattering

It is shown that the EMC-effect can be explained by the nuclear structure. The binding of nucleons is shown to play an important role. The contributions of mesons to the nuclear structure functions are discussed.     

A Hybrid Kinetic-Quantum Model for Stationary Electron Transport

Interface conditions between a classical transport model described by the Boltzmann equation and a quantum model described by a set of Schrödinger equations are presented in the one-dimensional stationary setting. These interface conditions, derived thanks to an asymptotic analysis of the Wigner transform, are shown to be flux-preserving and are used to build a hybrid model consisting of a quantum zone surrounded by two classical ones. The hybrid model is shown to be well posed when the potential is either prescribed or computed self-consistently, and the semiclassical limit of the problem is shown to give the right interface conditions between two kinetic regions (the electrostatic potential being fixed). This model can be used to describe far-from-equilibrium electron transport in a resonant tunneling diode.     

Semiclassical analysis of the nonequilibrium local polaron

A resonant level strongly coupled to a local phonon under nonequilibrium conditions is investigated. The nonequilibrium Hartree-Fock approximation is shown to correspond to approximating the steady state density matrix by delta functions at field values to which the local dynamics relaxes in a semiclassical limit. If multiple solutions exist, all are shown to make nonvanishing contributions to physical quantities: multistability does not exist. Departures from equilibrium are shown to produce decoherence, preventing the formation of a polaron feature in the spectral function. The formalism also applies to the nonequilibrium Kondo problem.     

Thetapinch experiments with trapped antiparallel magnetic fields

Experimental evidence is presented which shows that stability for a cylindrical plasma sheet confined by antiparallel magnetic fields is established for times which are longer than theoretically predicted growth times for tearing instabilities by at least an order of magnitude. It is shown that the enhanced stability is not due to wall effects, inertia effects, too short a pinching coil, finite Larmor radius and viscosity effects. One possible explanation for the stability is shown to be related to the level of initial plasma perturbation. Further the enhanced stability can be explained by the observed plasma rotation. It is shown by simple arguments that the rotation can cancel the tearing mode's growth and that the rotation itself is a result of the diffusion of angular momentum across the neutral surface enclosing the confined plasma.     

Convergence criteria for the Hartree iterative solution of the general self-consistent field equations

The traditional Hartree method of solving the Hartree-Fock equations, by repeated diagonalization and recalculation of the single-particle Hamiltonian, is expressed in terms of repeated unitary transformations and shown to be applicable to the general SCF (self-consistent field) equations. The necessary and sufficient conditions for convergence to a unique local SCF solution are derived and it is shown that only a small class of solutions are obtainable by this method.     

Optimization of the transfer function of an acoustooptic cell with an apodized piezoelectric transducer

It is shown that an apodized piezoelectric transducer can significantly reduce the side lobe level of the acoustooptic cell transfer function. Series and symmetric connections of the transducer sections and measures to suppress the effect of spurious elements arising in the electric circuit are proposed. In particular, the effect of spurious capacitances and inductances on the frequency response of the transducer is studied. It is shown that they violate the optimal condition for the suppression of the transfer function side lobes, especially at high frequencies. It is shown by calculations that the effect of spurious elements can be eliminated by the insertion of additional capacitors at 80 and 150 MHz.     

An integrable structure related with tridiagonal algebras

The standard generators of tridiagonal algebras, recently introduced by Terwilliger, are shown to generate a new (in)finite family of mutually commuting operators which extends the Dolan–Grady construction. The involution property relies on the tridiagonal algebraic structure associated with a deformation parameter q. Representations are shown to be generated from a class of quadratic algebras, namely, the reflection equations. The spectral problem is briefly discussed. Finally, related massive quantum integrable models are shown to be superintegrable.     

Scaling laws for plasma armatures in railguns

A methodology for deriving the electrical and thermodynamic properties of plasma armatures in railgun launchers is presented. The methodology is based on the solution to the one-dimensional, quasi-steady equations for the plasma armature. It is shown that the thermodynamic and transport properties for typical armature materials can be adequately represented by power-law curve fits in the temperature and pressure regimes of interest. To illustrate the methodology, detailed computations for both copper and aluminum armatures are performed. Some discussion is also presented for hydrogen armatures. It is shown that the armature properties predicted by the scaling laws agree very well with those derived from more detailed numerical solutions to the governing differential equations. It is shown that, for both aluminum and copper armatures, the electrical conductivity is a strong function of the current per unit rail height and a weak function of launcher geometry. This dependence is shown to be in reasonable agreement with experimental data compiled over a wide range of gun bore dimensions and operating conditions     

Fisher-based thermodynamics: its Legendre transform and concavity properties

It is shown that the Legendre-transform structure of thermodynamics can be replicated without any change if one replaces the entropy S by Fisher's information measure I. Also, the important thermodynamic property of concavity is shown to be obeyed by I. By this use of the Fisher information measure we develop a thermodynamics that seems to be able to treat equilibrium and nonequilibrium situations in a manner entirely similar to the conventional one.