We propose a mechanism by which density perturbations δρ/ρ∼${10}^{\mathrm{-}4}$ and a baryon asymmetry ${\mathit{n}}_{\mathit{B}}$/s∼${10}^{\mathrm{-}10}$ can naturally be generated in any realistic supersymmetric theory. By ‘‘naturally’’ we mean that the coefficient λ in the usual toy-model inflationary potential V=λ${\mathrm{\phi }}^4$ is related to the superpotential Yukawa coupling ${\lambda }^{\mathit{e}}$ which generates the electron mass. We identify a nine-parameter ‘‘quasiflat’’ direction which generates δρ/ρ through chaotic inflation and which leads to an Affleck-Dine valley (flat direction) where primordial baryogenesis occurs.

The astrophysics and the particle physics of solar neutrinos can be tested independently by two line signals induced by neutral (NC) and charged current (CC) neutrino reactions on ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, in a high-resolution, bolometric, 4-ton LiF detector. The NC γ-ray line signal measures the flux of neutrinos of all flavors with ${\mathit{E}}_{\nu }$>0.478 MeV, setting a firm empirical basis for the model-dependent links of the solar reaction chains. The CC signal from the model-independent ‘‘pep’’ neutrino line is a ‘‘yes/no’’ signal for flavor conservation. The shape of the CC $(—pep$)— line is a direct thermometric probe of the solar core.

The moment of inertia of the yrast superdeformed band in ${}_{}{}^{149}{}_{}{}^{}\mathrm{Gd}$ exhibits an unexpected bifurcation at high rotational frequency. States differing by four units of angular momentum show an energy shift of about 60 eV. This indicates the remnant of a new quantum number associated with the fourfold rotational symmetry.

We examine the empirical domain of validity of statistical theory, as applied to fission data on prefission neutron, charged particle, and γ-ray multiplicities. Systematics are found in the threshold excitation energy for the appearance of nonstatistical fission. From the data on systems with not too high fissility,, the relevant phenomenological parameter is the ratio of the threshold temperature ${\mathit{T}}_{\mathrm{thresh}}$ to the (temperature dependent) fission barrier height ${\mathit{E}}_{\mathrm{b}\mathrm{a}\mathrm{r}\left(\mathit{T}\right)}$. The statistical model reproduces the data for ${\mathit{T}}_{\mathrm{thresh}}$/${\mathit{E}}_{\mathrm{b}\mathrm{a}\mathrm{r}\left(\mathit{T}\right)<\mathrm{}0.26\mathrm{}}$±0.05 but underpredicts the multiplicities at higher ${\mathit{T}}_{\mathrm{thresh}}$/${\mathit{E}}_{\mathrm{b}\mathrm{a}\mathrm{r}\left(\mathit{T}\right)}$ independent of mass and fissility of the systems.

The line sharpening effect, one of the characteristics of the Auger resonant Raman effect when the bandwidth of exciting photons is smaller than the lifetime widths of the corresponding core levels, has been observed with clarity for the first time. The kinetic energies of the resonant Auger lines following the 3d→5p and 4d→6p excitations in Kr and Xe, respectively, display also linear dispersion when photon energy is scanned over the resonances.

We show that continuous-wave, two color excitation of three-level atoms opens new channels of irreversible population transfer between atomic levels. We point out that dynamically induced irreversibility leads to unanticipated phenomena such as the inversion of atomic transitions in cases where the upper atomic level has no conventional source of irreversible population pumping. The widely held view that coherent excitation is reversible is called into question.

A recently reported peak near 9.5 eV in the cross section for electron impact dissociative recombination of vibrationally cold ${\mathrm{H}}_3^{+}$ is due to four ${\mathrm{H}}_3$ resonance states. Using a complex Kohn, electron scattering variational method to obtain resonance energies and widths and a time-dependent wave packet calculation of the dissociation dynamics in the presence of autoionization, we obtain excellent agreement with the position, shape, and magnitude of the reported feature. Vibrational excitation of ${\mathrm{H}}_3^{+}$ is a dominant competing channel due to a high probability of autoionization during dissociation.

The structure of protonated acetylene (${\mathrm{C}}_2$${\mathrm{H}}_3^{+}$), including correlations, is measured and analyzed by an advanced Coulomb explosion imaging method. In the data analysis, it is essential to include large-amplitude motions of the nuclei within the molecule and many-body correlation features for revealing the correct structure. We find that the nuclear conformations in this molecule differ markedly from theoretical predictions and previous experimental findings.

The order ${\mathrm{\alpha }}^4$${\mathit{R}}_{\mathrm{\infty }}$ corrections to the fine-structure splitting of positronium P levels are found. The calculation is reduced to the ordinary perturbation theory for the nonrelativistic Schrödinger equation. The perturbation operators have the Breit-type structure and are obtained by calculating on-mass-shell diagrams. The correction found is -0.64 MHz for the $2^3$${\mathit{P}}_{0\mathrm{-}}$$2^1$${\mathit{P}}_1$ energy splitting.

We discuss two-point correlations of the actions of classical periodic orbits in chaotic systems. For systems where the semiclassical trace formula is exact and the spectral statistics follow random matrix theory, there exist nontrivial correlations between actions, which we express in a universal form. We illustrate this result with the analogous problem of the pair correlations between prime numbers. We also report on numerical studies of three chaotic systems where the semiclassical trace formula is only approximate, but nevertheless these unexpected action correlations are observed.

Single beam holographic grating recording, based on the photogalvanic coupling between orthogonal birefringent modes, is demonstrated in a photorefractive ${\mathrm{BaTiO}}_3$ crystal.

A novel scheme of injection and confinement of electrons is reported for the formation of a toroidal electron cloud in the presence of a static toroidal magnetic field. The scheme is based on the use of a combination of externally applied electric field and the self-consistent space charge field for the electron trapping and confinement. The time development of electron cloud potentials measured in the poloidal plane of the torus is presented. A potential well depth exceeding the initial kinetic energy of the electrons is observed, indicating collective effects. The effect of external field on the total charge and capacitance of the electron cloud is also presented.

Physical conditions are obtained to make the propagation velocity of a laser pulse and thus the phase velocity of the excited wake be at any desired value, including that equal to or greater than the speed of light. The provision of an active-plasma laser medium with an appropriately shaped pulse allows not only replenishment of laser energy loss to the wake field but also acceleration of the group velocity of photons. A stationary solitary solution in the accelerated frame is obtained from our model equations and simulations thereof for the laser, plasma, and atoms.

During the sustained phase of spheromak operation in the flux amplification compact toroid device, detailed observations were made on the discrete relaxation and toroidal current regeneration events that occurred throughout a typical quasiregular cycle. Measurements indicate that over such a cycle there appears to be a global self-organizing phenomenon which involves both the collapse and subsequent recovery of the closed flux surfaces. At the point of recovery, the partially relaxed state is characterized by a value of λ on the central region which is greater than that on the edge region.

We present neutron diffraction data on a 1:9 molar ratio methanol-water mixture in which isotope substitution is used to isolate the methyl hydrogen (M) to water hydrogen (H) pair correlation function. Spherical harmonic analysis of the data confirms the existence of a definite hydration shell of water molecules at a distance of ∼3.7 Å from the carbon atom in the methanol molecule. The water molecules in this shell form a disordered cage but retain the roughly tetrahedral local coordination found in pure water. Some degree of polarization of the water molecules in this shell is also apparent.

The interaction of C with Ni(100) has been studied by scanning tunneling microscopy (STM). The C atoms, imaged as ≊0.3 Å deep depressions consistent with theoretical predictions, are at low C coverages located in the fourfold hollow sites, causing a small radial displacement of the surrounding Ni atoms. Above a local critical coverage, C induces a disorder-order transition to a reconstruced phase, and the STM images reveal a coordinated 0.55 Å lateral clockwise-counterclockwise displacement of the topmost Ni atoms. A simple model for the driving force for this ‘‘clock’’ reconstruction is proposed.

We examine the pressure behavior of two S-induced deep levels, which arise from negatively charged broken-bond (${\mathit{DX}}^{\mathrm{-}}$) and on-site (${\mathit{D}}^{\mathrm{-}}$) geometries, in GaAs and InP, and find the ${\mathit{DX}}^{\mathrm{-}}$ state to be the ground state over the ${\mathit{D}}^{\mathrm{-}}$ and shallow donor states at pressures of 18 and 88 kbar, respectively, in good agreement with experimental data. The ${\mathit{DX}}^{\mathrm{-}}$ state is characterized by the conduction band structure, while the formation of the ${\mathit{D}}^{\mathrm{-}}$ state is closely related to the local chemical bonding, exhibiting the semiconductor-dependent pressure variation.

Shear rigidity percolation is studied on a simple square lattice where a fraction p of the area is filled by an elastic solid, and the rest by liquid. The presence of the liquid is shown to yield a new shear critical exponent τ at the percolation threshold. Through finite-size scaling calculations the value of τ is found to be 1.2±0.1, while similar calculations on solid-vacuum composites yield the 2D elastic critical exponent T=3.4±0.2, in excellent agreement with prior results. The underlying physics of the solid-liquid rigidity percolation is discussed.

A microscopic theory for the diffusive and vibrational motion of absorbed atoms on a solid surface is presented. We evaluate and analyze the dynamical structure factor. The quasielastic scattering peak is found to consist of mixed contributions from both diffusion and vibration. The vibrational peak in the dynamic structure factor indicates both a shift and broadening from anharmonic effects and frictional damping. Applied to Na on Cu(001) surface, the theory agrees quantitatively with recent experimental measurements.

Extended x-ray absorption fine structure studies have been performed above the oxygen K edge for ${\mathrm{SO}}_2$ in the gas phase as well as condensed and chemisorbed on Cu(100) and for CO chemisorbed on the same surface. The analysis of the pronounced oscillations shows that intramolecular bond lengths of low-Z molecules can be directly determined with high accuracy. The extended x-ray absorption fine structure technique thus possesses the unique capability of measuring these bond lengths in gas phase, condensed, and chemisorbed molecules.