An experiment is reported in which the specific heat of a 1 mm high sample of C${\mathrm{O}}_2$ has been measured to within 12 mdeg of its critical temperature. The results show that the exponent $\alpha =\frac{1}{8}$ both above an below $T_c$, a value in agreement with the Ising model but inconsistent with scaling law analyses of existing $\mathrm{PVT}$ data.

The driving toroidal electric field in Tokamaks is shown to lead to a significant pinching effect at low collision frequency. For ${\beta }_{\theta }=\frac{8\pi p}{B_{\theta }^{}{}_{}{}^2}<1\mathrm{}$, where $B_{\theta }$ is the poloidal field, this pinching is more rapid than outward diffusion in the banana and plateau regimes of toroidal transport theory.

Cooling by adiabatic freezing of ${\mathrm{He}}^3$ eventually comes to a dead end because the solid transforms into an antiferromagnet. It is shown that in the presence of a magnetic field the final temperature can be made arbitrarily low and is limited only by the starting temperature of the freezing process.

We propose a one-dimensional model of a superconducting link which is "weak" only insofar as it has a lower critical current than the superconductors on either side. According to appropriate solutions of the Ginzburg-Landau equations, the supercurrent $J$ is a single-valued, odd function of the phase change $\varphi$ across the link, which goes to zero at $\varphi =0\mathrm{}$ and $\varphi =\pi$ and tends to the Josephson relation $J\propto sin\varphi$ in the limit of a very weak link.

X-ray diffraction has been observed for the first time from material under shock compression. This was accomplished by directing a single pulse of x rays at LiF which was under compression from a shock wave, and observing the (200) diffraction line from the shock-compressed state. The experimental window for observing the effect was ∼20 nsec; the pressure behind the shock front was ∼130 kbar.

Second-order Raman-scattering spectra have been measured in TlBr single crystals as a function of exciting-light frequency at low temperatures. The results obtained indicate that as the exciting frequency approaches the first exciton peak frequency, a new resonant-scattering mechanism becomes important, as evidenced by the appearance and rapid increase of a sharp peak at twice the LO phonon frequency ($q=0\mathrm{}$), and by the absence of such a feature in analogous spectra taken for TlCl, where only off-resonant scattering is expected to occur.

We have observed self-steepening and narrowing of transverse heat pulses in pure NaF at high input-pulse powers when the ambient temperature is in the ballistic regime of the thermal-conductivity curve. The details of such nonlinear propagation of heat are found to be in agreement with the theory proposed by Tappert and Varma, which shows that under certain conditions heat pulses develop an instability.

Using an asymptotic analysis leading to a modified Korteweg-de Vries equation and a nonlinear parabolic equation, it is shown that under certain conditions on phonon dispersion and lattice anharmonicity, self-trapping of heat pulses occurs in solids at low temperatures.

A general method is described for obtaining a map of the variation of the electronic lifetime over the entire Fermi surface using the Dingle temperatures measured in the de Haas-van Alphen effect. The method is illustrated by presenting maps of the variation of the electron-impurity scattering lifetime for Au:Ag and Au:Fe dilute alloys.

The problem of exciton states is considered in the presence of the interactions of the electron and the hole with optical phonons. In the two limits exciton Bohr radius $r_{\mathrm{ex}}$ much smaller and much larger than the polaron radii $r_{e,h}^{}{}_{}{}^{*}$, the problem can be solved exactly. An interpolation scheme for obtaining results for intermediate values of the parameter $\frac{r_{\mathrm{ex}}}{r_{e,h}^{}{}_{}{}^{*}}$ is proposed. An effective nonlocal electron-hole potential is obtained which reduces to the physically expected results in various limits.

Nuclear magnetic resonance of ${}_{}{}^{55}{}_{}{}^{}\mathrm{Mn}$ nuclei, detected through its effect on the antiferromagnetic resonance, has been used to measure the zero-point spin reduction in the quadratic layer antiferromagnets ${\mathrm{K}}_2$Mn${\mathrm{F}}_4$ and ${\mathrm{Rb}}_2$Mn${\mathrm{F}}_4$. The result, including a small correction for supertransferred hyperfine effects, is $S-{〈S_z〉}_{T=0\mathrm{}}=0.17\mathrm{}\pm 0.03$, in excellent agreement with spin-wave theory.

We present experimental results on the ground-state bands of heavy even-even nuclei produced in the primary fission of ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$. Experimental values for the energy levels and lifetimes range from those typical of spherical nuclei to those associated with permanently deformed nuclei.

A solid-body model for neutron matter is proposed for calculating the equation of state for densities beyond the nuclear density using the Reid soft-core potential for the neutron-neutron interaction.

Recent experiments with intense linear electron beams have produced ions with energies exceeding the beam kinetic energy. We present a localized beam-pinch model explaining the phenomena.

We have observed coherent production of $K^{-}{\pi }^{+}{\pi }^{-}$ systems by $K^{-}$ beams on nuclei and have measured the coherent production rate in the $Q\left(1300\right)\mathrm{}$ region. Using the corresponding hydrogen and deuterium production rates we have calculated ${\sigma }_{Q^{-}}$, the $Q^{-}$-nucleon total cross section. We find ${\sigma }_{Q^{-}}={20.8}_{-9.0\mathrm{}}^{+7.2\mathrm{}}$ mb at 10 $\frac{\mathrm{GeV}}{c}$ and ${\sigma }_{Q^{-}}={20.8}_{-8.4\mathrm{}}^{+6.0\mathrm{}}$ mb at 12.7 $\frac{\mathrm{GeV}}{c}$.

We provide a nonexotic, kinematic interpretation of forward ${\Delta }^{-}$ production in the reactions $\mathrm{pn}\to {\Delta }^{-}p{\pi }^{+}$ and $\mathrm{pn}\to {\Delta }^{-}{\Delta }^{++}$ at high energy. We show that forward production of ${\Delta }^{-}$ in ${\Delta }^{-}p{\pi }^{+}$ is mediated by a simple diagram which includes one-pion exchange plus low-energy, off-shell ${\pi }^{-}p\to {\pi }^{+}{\Delta }^{-}$ scattering. The final state $n{\pi }^{-}{\Delta }^{++}$ is produced by a similar one-pion—exchange diagram. The sum of these diagrams imitates $\mathrm{pn}\to {\Delta }^{-}{\Delta }^{++}$. Our approach has the virtue of absolute normalization; both shapes of distributions and total cross sections are in excellent agreement with available data. We discuss other reactions in which the same mechanism operates, and propose tests of our scheme.

We propose that a substantial part of the observed behavior of inelastic electron-proton scattering is due to a nondiffractive component of virtual photon-proton scattering. The behavior of resonance electroproduction is shown to be related in a striking way to that of deep inelastic electron-proton scattering. We derive relations between the elastic and inelastic form factors and the threshold behavior of the inelastic structure functions in the scaling limit.

The theoretical possibility that there may exist charged spin-0 weak intermediate bosons, in addition to the usual spin-1 intermediate bosons, is discussed. Some of its experimental consequences are analyzed.

Observation of the first-sound attenuation in liquid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ under pressure has revealed a new relaxation mechanism which is not predicted by any present theory.

The field at a vortex center, $h_v$, was measured in a vanadium foil sample and extrapolated to zero temperature and zero flux density. For an isolated vortex at $T=0\mathrm{}$, $h=1780\mathrm{}\pm 240$ G. At all flux densities it appears that $\frac{\partial h_v}{\partial T}$ is nonzero, even as $T\to 0$.