By switching between linear and circular polarization in the irradiation of supersaturated solutions of the amino acid glycine in water with intense nanosecond pulses of near-infrared laser light, we have obtained the $\gamma$ and $\alpha$ phases, respectively, through nonphotochemical light-induced nucleation (NPLIN). This is the first report of light polarization controlling crystal structure. The intensity dependence of NPLIN in aqueous urea is also reported.

Electrically induced phosphorescence from a poly(para-phenylene) ladder-type polymer is observed for the first time and characterized using time resolved spectroscopy. Short-lived phosphorescence is also observed in gated fluorescence spectra and is found to be quenched reversibly by oxygen. Thermally activated triplet diffusion to covalently bound palladium sites, which are formed at a concentration of about 80 ppm in a side reaction during polymer synthesis, is believed to be the cause of this novel effect, which suggests a new approach to the design of efficient electroluminescent materials.

We study numerically the cooling of a young bare strange star and show that its thermal luminosity, mostly due to $e^{+}{e}^{-}$ pair production from the quark surface, may be much higher than the Eddington limit. The mean energy of photons far from the strange star is $\sim {10}^2\mathrm{k}\mathrm{e}\mathrm{V}$ or even more. This differs both qualitatively and quantitatively from the thermal emission from neutron stars and provides a definite observational signature for bare strange stars. It is shown that the energy gap of superconducting quark matter may be estimated from the light curves if it is in the range from $\sim 0.5\mathrm{M}\mathrm{e}\mathrm{V}$ to a few MeV.

We describe measurements of colloidal transport through arrays of micrometer-scale potential wells created with holographic optical tweezers. Varying the orientation of the trap array relative to the external driving force results in a hierarchy of lock-in transitions analogous to symmetry-selecting processes in a wide variety of systems. Focusing on colloid as a model system provides the first opportunity to observe the microscopic mechanisms of kinetic lock-in transitions and reveals a new class of statistically locked-in states. This particular realization also has immediate applications for continuously fractionating particles, biological cells, and macromolecules.

A new physical effect is reported. In single crystals of lithium niobate ($\mathrm{L}\mathrm{i}\mathrm{N}\mathrm{b}{\mathrm{O}}_{\mathrm{3}}$), we have observed an acoustical memory effect. An acoustical tone burst is stored inside the crystal and reemitted at a later time. This memory signal is related to the acousto-electrical properties of the ferroelectric medium. Futhermore, it is shown to be sensitive to both temperature and frequency.

We present a simple yet effective mechanism promoting cooperation under full anonymity by allowing for voluntary participation in public goods games. This natural extension leads to “rock-scissors-paper”–type cyclic dominance of the three strategies, cooperate, defect, and loner. In spatial settings with players arranged on a regular lattice, this results in interesting dynamical properties and intriguing spatiotemporal patterns. In particular, variations of the value of the public good leads to transitions between one-, two-, and three-strategy states which either are in the class of directed percolation or show interesting analogies to Ising-type models. Although volunteering is incapable of stabilizing cooperation, it efficiently prevents successful spreading of selfish behavior.

We consider vacuum polarization from massless scalar electrodynamics in de Sitter inflation. The theory exhibits a $3+1$ dimensional analog of the Schwinger mechanism in which a photon mass is dynamically generated. The mechanism is generic for light scalar fields that couple minimally to gravity. The nonvanishing of the photon mass during inflation may result in magnetic fields on cosmological scales.

We study the possible formation of large (mesoscopic) molecular ions in an ultracold degenerate bosonic gas doped with charged particles (ions). We show that the polarization potentials produced by the ionic impurities are capable of capturing hundreds of atoms into loosely bound states. We describe the spontaneous formation of these hollow molecular ions via phonon emission and suggest an optical technique for coherent stimulated transitions of condensate atoms into a specific bound state. These results open up new possibilities for manipulating tightly confined ensembles.

We have imaged a 2D buried Ni nanostructure at 8 nm resolution using coherent x-ray diffraction and the oversampling phasing method. By employing a 3D imaging reconstruction algorithm, for the first time we have experimentally determined the 3D structure of a noncrystalline nanostructured material at 50 nm resolution. The 2D and 3D imaging resolution is currently limited by the exposure time and the computing power, while the ultimate resolution is limited by the x-ray wavelengths. We believe these results pave the way for the development of atomic resolution 3D x-ray diffraction microscopy.

Gravitational holography is argued to render the cosmological constant stable against divergent quantum corrections, thus providing a technically natural solution to the cosmological constant problem. Evidence for quantum stability of the cosmological constant is illustrated in a number of examples including bulk descriptions in terms of delocalized degrees of freedom, boundary screen descriptions on stretched horizons, and nonsupersymmetric conformal field theories as dual descriptions of anti–de Sitter space. In an expanding universe, holographic quantum contributions to the stress-energy tensor are argued to be at most of order the energy density of the dominant matter component.

The presence of ${\mathrm{C}\mathrm{s}}^{+}$ ions in the pseudo-1D nanopores of zeolite ITQ-4, ${\mathrm{S}\mathrm{i}}_{32}{\mathrm{O}}_{64}$, is confirmed by x-ray diffraction and atomic pair distribution function analysis. Inside the nanopores the ${\mathrm{C}\mathrm{s}}^{+}$ ions are found to assemble in zigzag chains and thus form an extended, positively charged sublattice providing charge balance for a low-density electron gas also confined to the nanopores.

Molecular simulations for simple fluids in narrow slit-shaped carbon pores exhibit crystal-hexatic and hexatic-liquid transitions that are consistent with Kosterlitz-Thouless-Halperin-Nelson-Young theory. The temperature range over which the hexatic phase is stable is dramatically widened under confinement. Remarkably, the transitions, which are continuous for a single adsorbed layer, become weakly first order when the pore can accommodate two molecular layers. Nonlinear dielectric effect measurements for ${\mathrm{C}\mathrm{C}\mathrm{l}}_4$ and aniline in activated carbon fibers (pore width 1.4 nm) show divergence at these transitions, confirming the hexatic phase.

We constrain $f_{\nu }\equiv {\Omega }_{\nu }/{\Omega }_{\mathrm{m}}$, the fractional contribution of neutrinos to the total mass density in the Universe, by comparing the power spectrum of fluctuations derived from the 2 Degree Field Galaxy Redshift Survey with power spectra for models with four components: baryons, cold dark matter, massive neutrinos, and a cosmological constant. Adding constraints from independent cosmological probes we find $f_{\nu }<0.13$ (at 95% confidence) for a prior of $0.1<{\Omega }_{\mathrm{m}}<0.5$, and assuming the scalar spectral index $n=1$. This translates to an upper limit on the total neutrino mass $m_{\nu ,\mathrm{t}\mathrm{o}\mathrm{t}}<1.8\mathrm{e}\mathrm{V}$ for “concordance” values of ${\Omega }_{\mathrm{m}}$ and the Hubble constant.

Data analysis of an experiment in which photon splitting in atomic fields was observed is presented. The experiment was performed at the tagged photon beam of the ROKK-1M facility at the VEPP-4M collider. In the energy region of 120–450 MeV, statistics of $1.6\times {10}^9$ photons incident on the BGO target was collected. About 400 candidate photon-splitting events were reconstructed. Within the attained experimental accuracy, the experimental results are consistent with the calculated exact atomic-field cross section. The predictions obtained in the Born approximation differ significantly from the experimental results.

Spatially confined solutions of traveling convection rolls are determined numerically for binary mixtures such as ethanol-water. The appropriate field equations are solved in a vertical cross section of the rolls perpendicular to their axes subject to realistic horizontal boundary conditions. The localized convective states are stably and robustly sustained by strongly nonlinear mixing and complex flow-induced concentration redistribution. We elucidate how this enables their existence for strongly negative separation ratios at small subcritical heating rates below the saddle node of extended traveling convection rolls where the quiescent fluid is strongly stable.

We report the first observation of white-light emission from femtosecond laser-induced plasma in a water droplet. Such emission is not observed with water in a cell. The microdroplet acts as a lens, focusing the incident light to nanosized regions within itself and directing the emission from these regions primarily back toward the laser source. This focusing increases the intensity so that multiphoton ionization generates plasma and causes it to reach the critical density during the initial part of the pulse, enabling the rest of the pulse to heat the plasma enough to emit in the visible.

With the surge of research in quantum information, the issue of producing entangled states has gained prominence. Here, we show that judiciously bringing together two systems of strongly interacting electrons with vastly differing ground states—the gapped BCS superconductor and the Luttinger liquid—can result in quantum entanglement. We propose three sets of measurements involving single-walled metallic carbon nanotubes which have been shown to exhibit Luttinger liquid physics, to test our claim and as nanoscience experiments of interest in and of themselves.

We consider how to make best use of imperfect objects, such as defective analog and digital components. We show that perfect, or near-perfect, devices can be constructed by taking combinations of such defects. Any remaining objects can be recycled efficiently. In addition to its practical applications, our “defect combination problem” provides a novel generalization of classical optimization problems.

Observations of neutral-current $\nu$ interactions on deuterium in the Sudbury Neutrino Observatory are reported. Using the neutral current (NC), elastic scattering, and charged current reactions and assuming the standard ${}^8\mathrm{B}$ shape, the ${\nu }_e$ component of the ${}^8\mathrm{B}$ solar flux is ${\phi }_e{=1.76\mathrm{}}_{-0.05\mathrm{}}^{+0.05\mathrm{}}\left(\mathrm{stat}{)}_{-0.09\mathrm{}}^{+0.09\mathrm{}}\right(\mathrm{syst})\times {10}^6{\mathrm{cm}}^{-2\mathrm{}}{\mathrm{s}}^{-1\mathrm{}}$ for a kinetic energy threshold of 5 MeV. The non- ${\nu }_e$ component is ${\phi }_{\mu \tau }{=3.41\mathrm{}}_{-0.45\mathrm{}}^{+0.45\mathrm{}}\left(\mathrm{stat}{)}_{-0.45\mathrm{}}^{+0.48\mathrm{}}\right(\mathrm{syst})\times {10}^6{\mathrm{cm}}^{-2\mathrm{}}{\mathrm{s}}^{-1\mathrm{}}$, $5.3\sigma$ greater than zero, providing strong evidence for solar ${\nu }_e$ flavor transformation. The total flux measured with the NC reaction is ${\phi }_{\mathrm{NC}}{=5.09\mathrm{}}_{-0.43\mathrm{}}^{+0.44\mathrm{}}\left(\mathrm{stat}{)}_{-0.43\mathrm{}}^{+0.46\mathrm{}}\right(\mathrm{syst})\times {10}^6{\mathrm{cm}}^{-2\mathrm{}}{\mathrm{s}}^{-1\mathrm{}}$, consistent with solar models.

Transition states in phase space are identified and shown to regulate the rate of escape of asteroids temporarily captured in circumplanetary orbits. The transition states, similar to those occurring in chemical reaction dynamics, are then used to develop a statistical semianalytical theory for the rate of escape of asteroids temporarily captured by Mars. Theory and numerical simulations are found to agree to better than $1\%$. These calculations suggest that further development of transition state theory in celestial mechanics, as an alternative to large-scale numerical simulations, will be a fruitful approach to mass transport calculations.