We calculate the passage-time statistics of a gain-switched single-mode semiconductor laser with a weak, detuned injected signal. Results are given in terms of a relevant scaling parameter. We find that a weak injected signal can be detected by measurements of the mean passage time or its variance whenever its frequency is close to the one of the semiconductor lasers in the on state. In this case, the external signal is resonant with the laser field at the time when amplification becomes possible, and hence it triggers the switch-on more efficiently. The detection bandwidth is of the order of 50 GHz for the case considered.

Homodyne statistics when the light from a degenerate parametric oscillator (DPO) is mixed with coherent light from a local oscillator are discussed. By using dynamical models of these beams we discuss the photon sequences underlying the superposed beam in terms of photoelectric pulse sequences recorded by a detector. The field produced by the parametric oscillator is expressed in terms of two independent real Gaussian random variables. Using this property of the field variables, we derive the generating function for the photoelectron statistics analytically. From this generating function, expressions for the photoelectron-counting distribution, factorial moments, and the waiting-time distribution are derived. These quantities are directly measurable in photon-counting experiments. The results reported here are applicable to arbitrary strengths of the signal and the local-oscillator fields. We also show that, depending on the relative strength and relative phase between coherent light from the local oscillator and squeezed light from the DPO, the superposed light beam may exhibit many interesting nonclassical features. These and other effects are described and curves are presented to illustrate the behavior.

The density of the generalized oscillator strength per unit energy range of excitation for transitions from the ground state to the continuum of atomic hydrogen is computed beyond the plane-wave Born approximation. We use the Coulomb-Born approximation to compute the density for a variety of energy transfers and impact energies as a function of the momentum transfer. Our results show that the density approaches the standard plane-wave Born approximation and depends only upon the momentum transfer at impact energies as low as 50 eV.

We have developed a unified perspective for boundary conditions concerned with (I) a direct relativistic treatment of a δ-function potential and (II) the δ-function limit of solutions for relativistic treatment of peaked potential. We have presented a critical discussion of our findings, especially in the context of (i) certain conditions related very importantly to this unified perspective and (ii) the difficulty in making a choice between the approaches (I) and (II) on the basis of mathematical analyses alone.

The usual assumption of proton spin-symmetry species of hindered methyl groups is not consistent with the approximate nature of the multiply connected topology of rotation, which leads instead to a U(1) gauge theory in which wave packets transport three anyons around a void and gain phase due to a vector potential related to angular velocity. Though spin-symmetry species do not exist, some of their properties appear at low temperatures.

We show that there is a dual Aharonov-Casher topological effect [Phys. Rev. Lett. 53, 319 (1984)] on a neutral particle with electric dipole moment interacting with a magnetic field produced by magnetic monopoles.

We show that the Coulomb-center scattering matrix derived before in the semiclassical approximation (high Landau levels, n≫1) [Kuchiev and Sushkov, Phys. Lett. A 158, 69 (1991)] is in fact the exact quantum scattering matrix valid to n=0. The analytical continuation of the equation for discrete spectrum eigenstates into the region of resonances in continuum is fulfilled.

The variational method is used to find the ground-state energy of the molecular hydrogen ion, ${\mathrm{H}}_2^{+}$, by employing a linear combination of atomic orbitals (LCAO) of the Slater type, all with the same exponential parameter ζ. For the equilibrium position, R=2 a.u., eight-digit accuracy was achieved using 21 orbitals on each nucleus, with the highest principal quantum number, N=6. Beyond R=50, thirteen-digit accuracy is obtained. The wave function is given for various LCAO at the equilibrium position. Strategies developed here will be useful in our studies of polyatomic nonlinear molecules.

The mass difference, ${\mathit{m}}^1$${\mathrm{H}}_2$${\mathrm{O}}^{+}$-${\mathit{m}}^2$${\mathrm{HO}}^{+}$=0.001 548 296(12), corresponding to a mass-ratio precision of 6×${10}^{\mathrm{-}10}$, has been determined by Fourier-transform ion-cyclotron-resonance (FT ICR) mass spectrometry. Three related results are calculated from that mass difference: 2${\mathit{m}}^1$H-${\mathit{m}}^2$H=0.001 548 302(12) u; mass of the deuterium atom, 2.014 101 764(13) u; and deuteron binding energy, ${\mathit{S}}_{\mathit{n}}$${(}^2$H)=2 388 183(14) nu [=2 224 579(13) eV, in which 1 u=931.494 32(28) MeV]. In all three cases, the FT ICR mass-spectrometry-derived value improves significantly the precision of prior measured or recommended values.

For the many-anyon system in an external magnetic field, we derive the energy spectrum as an exact solution of the quantum eigenvalue problem with particular topological constraints. Our results agree with the numerical spectra recently obtained for the three- and the four-anyon systems.

We present an application of a configuration-interaction method for the continuum spectrum to He photoionization from the ground state to the doubly excited (2pnd) and (sp,2${\mathit{n}}^{\mathrm{-}}$) ${}_{}{}^1{}_{}{}^{}$${\mathit{P}}^{\mathit{o}}$ series, using a finite ${\mathit{L}}^2$-basis set constructed from a nearly complete set of spline-based one-particle hydrogenic orbitals. Our calculated resonance structures are in good agreement with the recent high-resolution synchrotron-radiation spectra [M. Domke, G. Remmers, and G. Kaindl, Phys. Rev. Lett. 69, 1171 (1992)]. Our calculated widths, resonance energies, and peak photoionization cross sections are also in close agreement with the most accurate existing theoretical results.

Previously reported large nonperturbative enhancements of bound-electron–positron pair production in heavy-ion reactions are shown to be extremely gauge dependent due to incompleteness of the basis set. Large-basis calculations for the Pb on Pb system put a probable upper limit of the order of 10 b on the correction to perturbative calculations of the K-orbit-electron–positron pair production at ultrarelativistic heavy-ion colliders such as RHIC; this is to be added to the perturbative value of about 115 b.

The various versions of the Jaynes-Cummings model and their q-deformed extensions are treated in a unified formalism based on the generalized deformed oscillator algebra. The evolution operator and physically interesting quantities such as the population inversion are calculated.

A paper by H. Puthoff [Phys. Rev. A 39, 2333 (1989)], which claims to derive Newtonian gravity from stochastic electrodynamics, contains a serious computational error. When the calculation is corrected, the resulting force is shown to be nongravitational and negligible.

Although mathematically self-consistent, Carlip’s approach to the reanalysis of Sakharov gravity is flawed by the neglect of important physical constraints associated with the interaction, and leads to an incorrect 1/${\mathit{R}}^4$ spatial dependence for the force. When appropriate physical cutoffs are incorporated into the modeling, however, inverse-square-law Newtonian gravity emerges as originally derived.

The mean energy of tunneling electrons at low temperatures may provide a very simple fundamental test between quantum mechanics and a class of alternative theories, the classical stochastic theories, since quantum theory and the stochastic alternatives differ in their descriptions of tunneling.

We calculate the signal-to-noise ratio in Mermin’s n-particle Bell inequality [Phys. Rev. Lett. 65, 1838 (1990)] based on source noise, data error, and statistical uncertainty. We find that the signal for violation grows exponentially faster than the exponentially growing noise, as long as the noise per detector or per particle is less than about 14%. Alternately, in the absence of noise a loophole-free test could be made with detector efficiencies as low as 71%.