In conventional Einstein-Podolsky-Rosen (EPR) experiments an unstable system decays into an entangled state of two or more particles. When appropriate measurements are made on this entangled state, phenomena are exhibited that run counter to our classical notions of local realism. Using a variant of a gedanken experiment proposed by Greenberger, Horn, and Zeilinger, it is shown that EPR effects can arise even when the particles come from independent widely separated sources.

We discuss the spectra of quantized chaotic billiards from the point of view of scattering theory. We show that the spectral and the resonance density functions both fluctuate about a common mean. A semiclassical treatment explains this in terms of classical scattering trajectories and periodic orbits of the Poincaré scattering map. This formalism is used to interpret recent experiments where the spectra of chaotic cavities were measured by microwave scattering.

A multimode, autonomously chaotic solid-state laser system has been controlled by the technique of occassional proportional feedback, related to the control scheme of Ott, Grebogi, and Yorke. We show that complex periodic wave forms can be stabilized in the laser output intensity. A detailed model of the system is not necessary. Our results indicate that this control technique may be widely applicable to autonomous, higher-dimensional chaotic systems, including globally coupled arrays of nonlinear oscillators.

It has recently been shown that a certain model field theory [which gives the Abelian Higgs model a global SU(2) symmetry by duplicating the scalar sector] possesses static finite-energy vortex solutions despite having a simply connected vacuum manifold. It is demonstrated here that they are stable or unstable according to whether ${\mathit{m}}_{\mathit{s}}$ is less than or greater than ${\mathit{m}}_{\mathit{v}}$ (where ${\mathit{m}}_{\mathit{s}}$ and ${\mathit{m}}_{\mathit{v}}$ are the masses of the Higgs and vector particles, respectively). At the boundary, ${\mathit{m}}_{\mathit{s}}$=${\mathit{m}}_{\mathit{v}}$, there is a two-parameter family of solutions all saturating a Bogomol’nyi bound. The relationship of the vortices to ${\mathrm{CP}}^{\mathit{n}}$ σ-model lumps is pointed out.

The deconfining transition in non-Abelian gauge theory is known to occur by a condensation of Wilson lines. By expanding around an appropriate Wilson-line background, it is possible at large N to analytically continue the confining phase to arbitrarily high temperatures, reaching a weak-coupling confinement regime. This is used to study the high-temperature partition function of an SU(N) electric flux tube. It is found that the partition function corresponds to that of a string theory with a number of world-sheet fields that diverges at short distance.

I discuss the ambiguities in distinguishing the standard model from superweak models using CP-violating neutral-B-meson decay asymmetries. There is a significant region of parameter space where it will be difficult to make the distinction even with 100 ${\mathrm{fb}}^{\mathrm{-}1}$ of luminosity at the Y(4S).

Using the CLEO II detector, we have accurately measured ${\mathit{D}}_{\mathit{s}}$ decay branching ratios relative to the φ${\mathrm{\pi }}^{+}$ mode for the η${\mathrm{\pi }}^{+}$ and η’${\mathrm{\pi }}^{+}$ states, for which there are conflicting claims; our results are 0.54±0.09±0.06 and 1.20±0.15±0.11, respectively.

We have observed the previously unseen η${\mathrm{\rho }}^{+}$ and η’${\mathrm{\rho }}^{+}$ decay model of the ${\mathit{D}}_{\mathit{s}}^{+}$, and measured branching ratios relative to the φ${\mathrm{\pi }}^{+}$ mode of 2.86±0.${38}_{\mathrm{-}0.38}^{+0.36\mathrm{}}$ and 3.44±0.${62}_{\mathrm{-}0.46}^{+0.44\mathrm{}}$, respectively. In addition, the relative branching ratio for the decay into φ${\mathrm{\rho }}^{+}$ is measured as 1.86±0.${26}_{\mathrm{-}0.40}^{+0.29\mathrm{}}$. Combining these new measurements with previous results and those in the preceding Letter, we account for ≊(79±26)% of ${\mathit{D}}_{\mathit{s}}$ decays.

The cross section for the ${}_{}{}^8{}_{}{}^{}\mathrm{Li}$(α,n${)}^{11}$B reaction, which is crucial to predictions of primordial nucleosynthesis in inhomogeneous models, has been measured using the radioactive-beam facility of the Institute for Physical and Chemical Research (RIKEN). The reaction cross section to all allowed ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ states was found to be larger than that to just the ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ ground state by about a factor of 5.

The heaviest known examples of proton radioactivity, ${}_{}{}^{160}{}_{}{}^{}\mathrm{Re}$ and ${}_{}{}^{156}{}_{}{}^{}\mathrm{Ta}$, have been discvovered. Evaporation residues from fusion reactions of 300 MeV ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ ions with ${}_{}{}^{106}{}_{}{}^{}\mathrm{Cd}$ targets have been mass separated in flight and implanted into a double-sided silicon strip detector. The measured proton energies, total half-lives, and proton branching ratios are 1261±6 keV, 790±160 μs, 91±10%, and 1022±13 keV, ${165}_{\mathrm{-}55}^{+165\mathrm{}}$ ms, ≊100% for ${}_{}{}^{160}{}_{}{}^{}\mathrm{Re}$ and ${}_{}{}^{156}{}_{}{}^{}\mathrm{Ta}$, respectively, indicating that the protons are emitted from a ${\mathit{d}}_{3/2}$ orbital in each case. An energy of 6537±16 keV has been measured for the ${}_{}{}^{160}{}_{}{}^{}\mathrm{Re}$ alpha decay branch.

We study the isospin-dependent component of the effective nucleon-nucleon interaction which causes the ΔT=1 (p,p’) and (p,n) reactions off nuclei. It is shown that, at intermediate energies, the modification to the impulse approximation comes from the g-matrix-type correction and the rearrangement term. They are numerically estimated with the isospin-asymmetric nuclear-matter reaction matrix approach. The isobaric-analog transitions ${}_{}{}^{42}{}_{}{}^{}\mathrm{Ca}$(p,n${)}^{42}$Sc and ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$(p,n${)}^{48}$Sc are analyzed.

We have observed a strong peak in the excitation function for the inelastic scattering reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{12}$C${,}^{12}$C($0_2^{+}$)${)}^{12}$C($0_2^{+}$) at an energy of ${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$=32.5 MeV. A recoil coincidence arrangement between two double-sided silicon strip detectors was used to detect the α particles from the decaying ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ nuclei, and the reconstructed reaction kinematics were used to calculate the two-body scattering Q value. This excitation-function structure may be interpreted as arising from very highly deformed α-particle chain configurations in the nucleus ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$.

Recent experiments have demonstrated the feasibility of orienting rotationally cooled polar molecules in an electric field. The anisotropy of the Stark effect allows molecules in low rotational states to be trapped in ‘‘pendular states,’’ confined to librate over a limited angular range about the field direction. We present calculations exhibiting the nature of these pendular states for a linear molecule and characteristic features of infrared and microwave spectra which become observable in strong fields.

Infrared-laser–molecular-beam spectroscopy has been used to observe strongly bound pendular states of the linear hydrogen cyanide trimer. The spectrum undergoes a dramatic evolution from that of a free rotor at zero electric field, with its characteristic P and R branch structure, to that indicative of a pendulum bound by a large electric field (corresponding to ω=μE/B=365). The result is an unprecedented degree of orientation for a linear molecule. The generality of using weakly bound complexes to orient even nonpolar molecules is discussed.

The hyperfine-quenched transition $2^3$${\mathit{P}}_{0\mathrm{-}}$$1^1$${\mathit{S}}_0$ has been observed in heliumlike gadolinium (${\mathrm{Gd}}^{62+}$) in the two isotopes ${}_{}{}^{155}{}_{}{}^{}\mathrm{Gd}$ and ${}_{}{}^{157}{}_{}{}^{}\mathrm{Gd}$. The lifetime for the transition (${\mathrm{\tau }}_0$) has been measured for each isotope and found to be ${\mathrm{\tau }}_0$(155)=13.43(27)×${10}^{\mathrm{-}12}$ sec and ${\mathrm{\tau }}_0$(157)=7.65(55)×${10}^{\mathrm{-}12}$ sec. From the measured lifetimes a value is inferred for the absolute value of the $2^3$${\mathit{P}}_{0\mathrm{-}}$$2^3$${\mathit{P}}_1$ fine-structuring splitting ‖Δ${\mathit{E}}_{0\mathrm{-}1}$‖ in ${\mathrm{Gd}}^{62+}$ with the result ‖Δ${\mathit{E}}_{0\mathrm{-}1}$‖=18.57(19) eV, where the error represents 1 standard deviation. This result is compared with calculations based on the multiconfiguration Dirac-Fock method and on the unified method.

Laser excitation (photodissociation) and absorption spectroscopy of ${\mathrm{Ne}}_2$ ${\mathit{a}}^3$${\mathrm{\Sigma }}_{\mathit{u}}^{+}$ beyond the ${\mathit{v}}^{+}$=0 limit of the ${\mathrm{Ne}}_2^{+}$ ground electronic state (${\mathit{X}}^2$${\mathrm{\Sigma }}_{\mathit{u}}^{+}$) has revealed several distinct series of Fano-type windows superimposed onto predissociative and absorption continua. Resonances attributed to npσ←${\mathit{a}}^3$${\mathrm{\Sigma }}_{\mathit{u}}^{+}$ Rydberg-Rydberg transitions converging to ${\mathit{v}}^{+}$=1–3 of the ${\mathit{X}}^2$${\mathrm{\Sigma }}_{\mathit{u}}^{+}$ state are observed but apparent windows appear in the ${\mathit{a}}^3$${\mathrm{\Sigma }}_{\mathit{u}}^{+}$ absorption spectrum only for ${\mathit{v}}^{+}$=1 ion core Rydberg states. In contrast, IallR ${\mathit{v}}^{+}$=2 and 3 ion core states occur as positive absorptions. Comparison of the photoabsorption and excitation spectra shows clear evidences of the competition between autoionization and predissociation, but the general dominance of dissociation as the exit channel.

We have investigated multielectron capture processes in collisions of ${\mathrm{Ar}}^{9+}$ on Ar by measuring the resulting Auger electrons in coincidence with charge-state-analyzed target ions. In this way it was possible to reconstruct partial electron energy spectra, each corresponding to a particular number of initially captured electrons. The spectra are compared with predictions of the extended classical over-barrier model. Strong evidence is found that Auger cascades play an important role for the deexcitation of the highly excited ions, formed by multielectron capture.

The fluctuation in the plasma current density is measured in the MST reversed-field-pinch experiment. Such fluctuations, ad the measured radial profile of the k spectrum of magnetic fluctuations, support the view that low-frequency fluctuations (f<30 kHz) are tearing modes and high-frequency fluctuations (30 kHz<f<250 kHz) are localized turbulence in resonance with the local equilibrium magnetic field (i.e., k⋅B=0). Correlation of current-density and magnetic fluctuations (〈j${\mathrm{̃}}_{\mathrm{\parallel }}$B${\mathrm{̃}}_{\mathit{r}}$〉) demonstrates that radial particle transport from particle motion parallel to a fluctuating magnetic field is ambipolar over the full frequency range.

Using velocity-analyzed cold neutrons we observed the production of ultracold neutrons in superfluid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ at 0.45 to 1.5 K. Ultracold neutrons are produced for an incident neutron wavelength of 8.78±0.06 Å which agrees with the single-phonon emission theory. The temperature variation of the ultracold-neutron storage lifetime is also discussed.

This paper reports the discovery of a new vortex phenomenon in superfluid ${}_{}{}^3{}_{}{}^{}\mathit{B}$. A single filament of quantized vortex line precesses as a solid body around a wire extending along the axis of a cylinder. The precession frequency equals the angular velocity of the apparatus at which the presence of a single quantum of circulation minimizes the system’s free energy. The period of precession is related to the circulation quantum and the dimensions of the apparatus. Thus a measurement of the precession period is an accurate determination of the quantum unit. We find κ=(1.020±0.03)h/2${\mathit{m}}_3$, where ${\mathit{m}}_3$ is the mass of the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ atom.