A macroscopic uncertainty principle has been invoked as an explanation for the anomalously high attenuation of third sound in certain thickness regimes of liquid-He films. The propagation criterion deduced from this idea appears to be in accord with experiment. We outline here a microscopic mechanism which gives rise to a large attenuation and which yields a propagation criterion essentially equivalent to the one proposed as a macroscopic uncertainty principle. We find that the nonlinearities inherent in the problem play the significant role in producing this attenuation.

By using electron-microscope techniques it is possible to observe concentration fluctuations above the consolute point in "real space" in a glass-forming liquid mixture. The method is based on the rapid quenching of these fluctuations. We report the first measurements of this kind in a sodium-borosilicate melt of near critical composition. We discuss the relation between relevant relaxation parameters and the rate of quenching.

Enhanced absorption of an electromagnetic wave near ${\omega }_{\mathrm{pe}}$ was observed coincident with the onset of parametric decay instability in a $Q$-device plasma. The effective collision frequency ${\nu }_{\mathrm{eff}}={\nu }_{\mathrm{ei}}{\left(\frac{E}{E_c}\right)}^2$.

We report here the proton spin-lattice relaxation time ${\left(T_1\right)}_{\mathrm{CF}}$ measured in $p$-methoxybenzylidene $p-n$ butylaniline at two frequencies in a temperature range of about 25°C just above the nematic-isotropic transition. We have determined the correlation time for critical fluctuations, ${\tau }_{\mathrm{CF}}$, using a simple extension of the Bloembergen-Purcell-Pound theory which relates ${\tau }_{\mathrm{CF}}$ and ${\left(T_1\right)}_{\mathrm{CF}}$. The temperature dependence ${\tau }_{\mathrm{CF}}$ is in good agreement with the de Gennes theory and with experimental results of Stinson and Litster.

The thermal conductivity of a sample of Teflon was measured in the temperature range 0.17 to 4.0°K. A good fit to these data was obtained by using dislocation scattering of phonons and a Debye ${\omega }^2$ frequency distribution.

A new analytic procedure which allows one to recognize anharmonic behavior at any temperature is applied to the measured heat capacity of LiCl. The results imply that LiCl experiences an anomalous anharmonicity similar to that found in the so-called quantum solids. This anharmonicity corresponds to an apparent increase of the lattice frequencies with increasing temperature and can be understood in terms of the excess interstitial volume around the positive ions. These size-disparity arguments lead one to expect this anomalous behavior in a number of solids.

We report the first direct experimental evidence for the inversion-asymmetry splitting of the conduction band of InSb. Band-structure information and deformation potentials are obtained from Shubnikov—de Haas measurements by comparison with a theoretical model.

By using tunable dye lasers, the third-order optical nonlinear susceptibility ${\chi }^{\mathrm{}\left(3\right)\mathrm{}}(-{\omega }_3,{\omega }_1,{\omega }_1-{\omega }_2)$ is studied in LiNb${\mathrm{O}}_3$. ${\chi }^{\mathrm{}\left(3\right)\mathrm{}}$ shows resonant enhancement when ${\omega }_1-{\omega }_2$ is near the polariton frequencies. This behavior is explained in terms of a nonlinear force which drives the polariton modes strongly whenever momentum matching is satisfied.

An oscillatory, nonlocal contribution to the electromagnetic generation of shear acoustic waves in metals has been observed when the magnetic field is perpendicular to the propagation direction. Previous observations of electromagnetic generation of shear acoustic waves have been limited to the field being parallel to the propagation direction. Our observations are explained by considering forces on the lattice that arise from both the directly induced skin-depth electric field and the electric fields due to Gantmakhersplash current sheets.

A one-electron energy diagram is suggested for magnetite, which is consistent with recent soft-x-ray emission and absorption spectra, cathodoluminescence, and optical-absorption data.

A multi-data-set optical-model search code has been used to produce a set of mean geometry parameters for ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ nuclei incident on medium-weight nuclei. Using this geometry, the energy dependence of the volume integrals of the real and imaginary potentials has been obtained.

The $g$ factor of the first excited $2^{+}$ state of ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$ has been measured to be $g=1.43\mathrm{}\pm 0.28$. The $0\to 2\to 0$ (${}_{}{}^{16}{}_{}{}^{}\mathrm{O},\gamma$) angular correlation through the 1.4-psec mean-life state was precessed using the transient magnetic field effective in iron on Coulomb-excited and recoiled ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$. This result is in agreement with a quite pure ${\left(f_{\frac{7}{2}}\right)}^{-2\mathrm{}}$ shell-model configuration for the state.

A new technique for measuring ion cyclotron frequencies has been developed. We report the results $\frac{{\mu }_p^{\prime }}{{\mu }_N}=2.792\mathrm{}786\pm 0.000017$ (6.0 ppm), and the mass difference $\mathrm{H}_2^{}{}_{}{}^{+}$-${\mathrm{D}}^{+}$ = 1548.22 ± 0.20 μu. These are in agreement with previous measurements.

In order that the effect of graviation of the thermal background neutrinos on the expansion of the universe not be too severe, their mass should be less than $8 \frac{\mathrm{eV}}{c^2}$.

In a scintillation-counter experiment we have obtained evidence for a neutral meson denoted $M^0\mathrm{}\left(1150\right)\mathrm{}$ with a mass of 1148.3±3.3 MeV and a width of ${15.0}_{-11.7\mathrm{}}^{+9.0\mathrm{}}$ MeV produced in the reaction ${\pi }^{-}+p\to M^0+n$ at 2.4 $\frac{\mathrm{GeV}}{c}$.

New data are presented on ${\pi }^{-}$ production in inclusive $\mathrm{pp}$ interactions at 13, 18, 21, 24, and $28.5 \frac{\mathrm{GeV}}{c}$. Mean values $〈n〉$, $〈n(n-1\mathrm{})\mathrm{}〉$, and the associated multiplicity $〈n\left(y\right)-1\mathrm{}〉$ are given as functions of $s$. Single- and two-particle spectra are presented. The nova model reproduces our two-pion inclusive distributions very well and thus explains strong correlations found between $\pi$' s as a simple manifestation of small inelasticity, observed previously in single-particle spectra.

We present results of a search for the decay mode $K^{+}\to {\pi }^{-}{e}^{+}{\mu }^{+}$ which requires doubly charged weak currents for its existence. Limits are also obtained on the branching ratios for the decay modes $K^{+}\to {\pi }^{+}{e}^{+}{\mu }^{-}$ and $K^{+}\to {\pi }^{+}{e}^{+}{e}^{-}$. We give a comparison of some present experimental limits on neutral and doubly charged weak currents.

We present estimates of the amplitudes for the reactions ${\nu }_{\mu }+e\to {\nu }_{\mu }+e$ and $\nu +p\to \nu +p$ in the models of Georgi and Glashow, and of Lee, Prentki, and Zumino. In these renormalizable models of weak and electromagnetic interactions, the above processes arise only in second order. The amplitudes are of the order $G_F\alpha$: They are neither enhanced nor suppressed.

The use of data from cosmic-ray interactions with dense targets is discussed from the point of view of extracting information on scaling at high energies. We present a result which relates single-particle distributions on nuclear targets to single-particle distributions on nucleons. Contrary to the conclusion first drawn from these data, we find no serious conflict between present data and a flat pionization region.

We show that in the Penning-ionizing collision $\mathrm{He}\left(2^3{S}_1\right)+X\to \mathrm{He}\left(1^1{S}_0\right)+{\left(X^{+}\right)}^{*}+e$ the precession of the ${\mathrm{He}}^m$ spin at its Larmor frequency forces the $J$ polarization of the Penning ion to rotate at the same frequency but shifted in phase. The tangent of the phase shift is proportional to the lifetime of the ionic state and presents a unique method for measuring excited-ion lifetimes.