In natural and synthetic materials having non-racemic chiral centers, chirality and structural ordering each play a distinct role in the formation of ordered states. Configurational chirality can be extended to morphological chirality when the phase structures possess low liquid crystalline order. In the crystalline states the crystallization process suppresses the chiral helical morphology due to strong ordering interactions. In this Letter, we report the first observation of helical single lamellar crystals of synthetic non-racemic chiral polymers. Experimental evidence shows that the molecular chains twist along both the long and short axes of the helical lamellar crystals, which is the first time a double-twist molecular orientation in a helical crystal has been observed.

Bohr's correspondence principle, i.e., the expectation that the semiclassical approximation works better for states with greater quantum numbers, is shown to break down in all quantum systems in which the asymptotic interaction between the fragments behaves as ${-C}_n/r^n$ with $n>\mathrm{}2\mathrm{}$.

Experiments are performed to demonstrate the generation and propagation of acoustic solitary waves in an air-filled tube with a periodic array of Helmholtz resonators connected axially. The purpose is to verify the theoretical findings made so far that nonlinear acoustic waves do not evolve into a shock but into a solitary wave propagating steadily without any change of its smooth profile. To identify the solitary wave, the temporal pressure profile is compared directly with the theoretical profile of the solitary wave. Also checked are the relation between the peak sound pressure of the solitary wave and its half-value width in time, and the relation between the peak sound pressure and the deviation of propagation speed from sound speed. The experimental results show good quantitative agreement with the theory.

We present an analytical theory of susceptibility induced nuclear spin dephasing in the capillary network of myocardium. Using a strong collision approach, equations are obtained for the relaxation rate of the free induction and the spin echo decay. Simulation and experimental data are well predicted by the theory. Since paramagnetic deoxyhemoglobin as the origin of nuclear spin dephasing has a higher tissue concentration in myocardium supplied by a stenotic, i.e., significantly narrowed, coronary artery, spin dephasing might serve as a diagnostic tool. Our approach can be modified for capillary networks in other tissues than myocardium and may be applied in material science.

We report observations of a new quasistatic nonequilibrium phenomenon in the density of electronic states (DOS) of a superconductor. Tunneling measurements of the DOS of ultrathin Al films, at the spin paramagnetically limited parallel magnetic field transition, reveal a strongly hysteretic DOS spectrum. We show that the hysteresis can be characterized as a quasistatic state memory effect in which the state of a film (normal or superconducting) is determined by its state prior to entering the hysteretic region. We also show that state memory can lead to the onset of superconductivity with increasing temperature, i.e., reentrance.

With the aim of constraining the structural properties of neutron stars and the equation of state of dense matter, we study sudden spin-ups, glitches, occurring in the Vela pulsar and in six other pulsars. We present evidence that glitches represent a self-regulating instability for which the star prepares over a waiting time. The angular momentum requirements of glitches in Vela indicate that $\ge 1.4\%$ of the star's moment of inertia drives these events. If glitches originate in the liquid of the inner crust, Vela's “radiation radius” $R_{\infty }$ must exceed $\simeq 12\mathrm{km}$ for a mass of ${1.4M}_{\odot }$. Observational tests of whether other neutron stars obey this constraint will be possible in the near future.

We demonstrate that local transformations on a composite quantum system can be enhanced in the presence of certain entangled states. These extra states act much like catalysts in a chemical reaction: they allow otherwise impossible local transformations to be realized, without being consumed in any way. In particular, we show that this effect can considerably improve the efficiency of entanglement concentration procedures for finite states.

The number density and orientation of molecules at the surface of a total-internal-reflection-ring minicavity are probed with extremely high sensitivity in a novel realization of the cavity ring-down optical absorption experiment. The modes of the ultralow-loss cavity, which are excited by photon tunneling, have long lifetimes that are sensitive to the presence of absorbing species in the evanescent field near a cavity facet. The total-internal-reflection-ring cavity extends cavity ring-down spectroscopy to surfaces and condensed matter, permitting a wide range of novel fundamental studies and applications. Routine single molecule detection may ultimately be feasible.

We use the method of adiabatic following to prepare a single molecule in its fluorescing excited state. Spontaneous emission from this state gives rise to a single photon. With our current experimental conditions, up to $74\%$ of the sweeps lead to the emission of a single photon. Since the adiabatic passage is done on command, the molecule performs as a high rate source of triggered photons. The experimental results are in quantitative agreement with quantum Monte Carlo simulations.

Transmission metallic gratings with very narrow and deep enough slits can exhibit transmission resonances for wavelengths larger than the period of the grating. By using a transfer matrix formalism and a quasianalytical model based on a modal expansion, we show that there are two possible ways of transferring light from the upper surface to the lower one: by the excitation of coupled surface plasmon polaritons on both surfaces of the metallic grating or by the coupling of incident plane waves with waveguide resonances located in the slits. Both mechanisms can lead to almost perfect transmittance for those particular resonances.

We show that coorbital dynamics at large eccentricity and inclination exhibit hitherto unknown types of stable motion in the gravitational three-body problem. In the solar system, the secular stability is observed in the evolution of specific near-Earth asteroids. In particular, the slow diffusion of such objects through the Earth's coorbital region which leads to temporary capture suggests the existence of undiscovered retrograde moons of the Earth. In the Coulomb problem, the Kozai resonance is a primary candidate for stable low angular momentum states in two-electron atoms.

Thin films of Cs are covered with $\frac{1}{100}$ of a monolayer of Fe or Co. Then the impurities are covered with several atomic layers of Cs. The magnetization of the films is measured by means of the anomalous Hall effect. The magnetization follows a Brillouin function with a magnetic moment of about 8 Bohr magnetons for Co on the surface and in the bulk of the Cs. For the Fe impurities, a magnetic moment of 7 Bohr magnetons is observed. These large moments suggest that the $3d$ impurities polarize the conduction electrons of the Cs similar to the giant moments in Pd.

We introduce a new method of controlling chaos that retains the essential features of occasional proportional feedback, but is much simpler to implement. We demonstrate control on a simple piecewise-linear Rossler circuit operating near 1 kHz and a Colpitts oscillator with a fundamental frequency of 19 MHz. As a result of the simplicity of our technique, control of chaos has been accomplished for the fastest chaotic system reported to date.

We used a spatially broadband optical parametric amplifier for image amplification. In the phase-sensitive configuration of the amplifier, we observed noiseless amplification of input images. For a gain of $\simeq 2.5$, we measured noise-figure values of ( $0.2\pm 0.6$) and ( $0.4\pm 0.5$) dB, respectively, for two amplifiers of different lengths. These experimental values agree with theory (for an ideal noiseless amplifier the noise figure is 0 dB) and are almost 2 dB lower than the quantum limit of an ideal phase-insensitive amplifier.

In open-shield systems, we have derived current conditions that lead to remarkable magnetic-field confinement, which we call “supershielding.” The freedom to vary both primary and shield currents is important in solving the conditions. Solutions leading to very effective shielding are illustrated by the simple system of two parallel flat strips. Generalizations include other geometries, internal shielding, and electric-field confinement. An industrial coil design serves as a reference for practical issues. We discuss mathematical limits, via a “seesaw” approach, to “perfect shielding.”

Quantum jumps between Fock states of a one-electron oscillator reveal the quantum limit of a cyclotron. With a surrounding cavity inhibiting synchrotron radiation 140-fold, the jumps show a 13 s Fock state lifetime and a cyclotron in thermal equilibrium with 1.6 to 4.2 K blackbody photons. These disappear by 80 mK, a temperature 50 times lower than previously achieved with an isolated elementary particle. The cyclotron stays in its ground state until a resonant photon is injected. A quantum cyclotron offers a new route to measuring the electron magnetic moment and the fine structure constant.

We show that results from the theory of random matrices are potentially of great interest to understand the statistical structure of the empirical correlation matrices appearing in the study of multivariate time series. The central result of the present study, which focuses on the case of financial price fluctuations, is the remarkable agreement between the theoretical prediction (based on the assumption that the correlation matrix is random) and empirical data concerning the density of eigenvalues associated to the time series of the different stocks of the S&P 500 (or other major markets). In particular, the present study raises serious doubts on the blind use of empirical correlation matrices for risk management.

We use methods of random matrix theory to analyze the cross-correlation matrix $\mathbf{C}$ of stock price changes of the largest 1000 U.S. companies for the 2-year period 1994–1995. We find that the statistics of most of the eigenvalues in the spectrum of $\mathbf{C}$ agree with the predictions of random matrix theory, but there are deviations for a few of the largest eigenvalues. We find that $\mathbf{C}$ has the universal properties of the Gaussian orthogonal ensemble of random matrices. Furthermore, we analyze the eigenvectors of $\mathbf{C}$ through their inverse participation ratio and find eigenvectors with large ratios at both edges of the eigenvalue spectrum—a situation reminiscent of localization theory results.

Following a prediction by Smolańczuk [Phys. Rev. C 59, 2634 (1999)], we searched for superheavy element formation in the bombardment of ${}^{208}\mathrm{Pb}$ with 449-MeV ${}^{86}\mathrm{Kr}$ ions. We have observed three decay chains, each consisting of an implanted heavy atom and six subsequent $\alpha$ decays, correlated in time and position. In these decay chains, a rapid (ms) sequence of high energy $\alpha$ particles ( $E_{\alpha }\ge 10\mathrm{MeV}$) indicates the decay of a new high- $Z$ element. The observed chains are consistent with the formation of ${}_{}{}^{293}{}_{}{}^{}118$ and its decay by sequential $\alpha$-particle emission to ${}_{}{}^{289}{}_{}{}^{}116$, ${}_{}{}^{285}{}_{}{}^{}114$, ${}_{}{}^{281}{}_{}{}^{}112$, ${}_{}{}^{277}{}_{}{}^{}110$, ${}^{273}\mathrm{Hs}$ ( $Z=108\mathrm{}$) and ${}^{269}\mathrm{Sg}$ ( $Z=106\mathrm{}$). The production cross section is ${2.2}_{-0.8\mathrm{}}^{+2.6\mathrm{}}\mathrm{pb}$.

We address the dynamics of a drop with viscosity $\lambda \eta$ breaking up inside another fluid of viscosity $\eta$. We track the time evolution of the drop near snap-off in the experiments and then compare with a scaling theory developed for $\lambda =1\mathrm{}$. The theory is in excellent agreement with both the experiments and the previous simulations of Lister and Stone. Finally, we also investigate the $\lambda$ dependence of the drop shape and breaking rate, and develop a simple theory for the latter.