Showing papers in "Annals of Physics in 1961"

TL;DR: In this article, two genuinely quantum models for an antiferromagnetic linear chain with nearest neighbor interactions are constructed and solved exactly, in the sense that the ground state, all the elementary excitations and the free energy are found.

TL;DR: In this article, a general treatment of the infrared divergence problem in quantum electrodynamics is given, where the main feature of this treatment is the separation of infrared divergences as multiplicative factors, which are treated to all order of perturbation theory, and the conversion of the residual perturbations expansion into one which has no infrared divergence, and hence no need for an infrared cutoff.

TL;DR: The theory of turbulence in an incompressible fluid is formulated using methods similar to those of quantum field theory as discussed by the authors, and the terms in the perturbation series are shown to be in one to one correspondence with certain diagrams analogous to Feynman diagrams.

TL;DR: In this paper, the relativistic quantum theory of Fermi Dirac fields of arbitrary spin is investigated and a general theorem is proved which aserts that for fields of half integral spin > 1 2, the possibility of a consistent quantization requires that the equal-time anticommutators must be functions of the other fields to which the field in question is coupled.

TL;DR: In this paper, the Riemannian metric of Newton's general relativity is replaced by a linear coordinate transformation of a tensor tensor field, and the effect of a gravitational potential is to change the effective charge and mass of particles, rather than the metric.

TL;DR: In this article, the influence of pairing forces on the collective vibrations in nuclei is studied using a perturbation expansion, and the result is found to agree with that given by Belyaev using the superconductivity approximation except that here the number of particles is conserved.

TL;DR: In this article, the question of the localizability of the energy in gravitational fields is discussed once more, and it is shown that the expression for the energy density, derived in an earlier paper γ, does not have all the properties required for a satisfactory description of energy distribution.

TL;DR: In this paper, an approximate method of high reliability has been devised to solve for the abundance distributions resulting from the exposure of seed nuclei such as Fe56, to a weak neutron flux in stars.

TL;DR: In this article, the influence of localized impurities in solids may be represented either by (i) the effect of randomly distributed classical scattering centers for which only averaged quantities are meaningful or, as proved in this paper, by an equivalent quantum description which incorporates both the random character and the process of averaging.

TL;DR: Cubic and quartic anharmonic contributions to the Helmoholtz free energy of a crystal are derived as functions of temperature for a general force constant model of the crystal.

TL;DR: Generalized free fields as mentioned in this paper are a generalization of the free field in which the commutator is a c -number but does not satisfy a homogeneous Klein-Gordon equation.

TL;DR: In this paper, the Gibbsian thermodynamics of phase equilibrium is distinguished from the thermodynamic of Clausius and Kelvin by defining a set of additive conserved quantities (invariants): the internal energy, and the mole numbers of the independent chemical components.

TL;DR: In this paper, the guiding center motion of a charged particle in an electromagnetic field is obtained simultaneously and deductively, without considering individually the special geometric situations in which one effect or another occurs alone.

TL;DR: In this paper, the Yang-Mills trick is used to obtain theories of vector bosons invariant under continuous groups of coordinate-dependent linear transformations, and these theories are expressed as superpositions of simple Lie algebras.

TL;DR: In this article, an effective range theory for systems of many coupled two-body channels with angular momenta li is developed for the case of two coupled channels with multiple angular moments.

TL;DR: In this paper, a theoretical description of the ground state and low excited states of liquid He4 is developed in terms of a set of correlated basis functions, and matrix elements of the identity and Hamiltonian operator are evaluated by systematic application of a generalized Kirkwood type superposition approximation.

TL;DR: In this article, it has been shown that the behavior of calculated results using variational principles for scattering problems is rather different from that previously known for bound-state problems, as more and more adjustable terms are added to the trial function, the "stationary" value for the phase shift does not converge smoothly, but may on occasion turn out to be grossly inaccurate.

TL;DR: In this article, the quasielastic p-p scattering in the deuteron has been studied at 145 Mev and cross sections and asymmetries in a polarized beam have been measured.

TL;DR: In this article, it was shown that a weak Lagrangian proportional to the trace of |Jλ†|Jλ satisfies the ΔT = 12 rule, and that parity mixtures are allowed for T = 12 and T = 1 currents, but not for the T = 32 current.

TL;DR: In this article, the thermodynamic ion displacement correlation function of the phonon field was investigated in a crystal and especially in a metal. But the analysis was performed at a finite temperature, and the results showed that it is bounded and invertible everywhere off the real axis.

TL;DR: The cubic and quartic anharmonic contributions to the Helmholtz free energy of a face-centered cubic crystal with nearest neighbor, central force interactions, were computed in the limit of low temperatures as discussed by the authors.

TL;DR: In this paper, the authors explore the possibility of discriminating between equivalent potentials (i.e., potentials reproducing the same phase shifts and bound state energies for the two-body problem) by making use of three-body amplitudes.

TL;DR: In this article, the authors used a combination of statistical and optical models to obtain information on level structure, to determine cross sections for gamma-ray excitation, and to make a test of the predictions of inelastic scattering cross sections computed by combining the statistical model and optical model.

TL;DR: In this article, the angular distribution of neutrons scattered at resonances was measured for the zero-spin nuclei C12, O16, Si, and S32 as well as for the isotopes Li6 and Li7 and the results were presented in terms of the least square values of the coefficients in a Legendre-polynomial expansion of the differential scattering cross section relative to the laboratory system of coordinates.

TL;DR: The extent to which nuclei can appear "black" is discussed in this paper, and it is shown that direct reaction calculations sometimes show the oscillatory angular distributions which are characteristic of surface reactions.

TL;DR: In this article, the problem of the physical solutions of the Dirac equation for classical charges is not the usual initial value problem of Newtonian dynamics where the motion is determied by initial position and velocity.

TL;DR: In this paper, it was shown that the observable effects of external magnetic fields on the scattering of an electron in bound state problems arise not from forces exerted by the magnetic fields or by their vector potentials, but from modification of the quantum conditions.

TL;DR: In this paper, a generalization of the Fokker-planck equation is derived for the evolution in time of the distribution function through these quasi-equilibrium distributions, which yields the distribution of the electrons in energy and angle as a function of time.

TL;DR: In this paper, the total rate and the electron energy spectrum were calculated for the decay of a negative muon bound in an atomic 1s state, using relativistic electron and muon wave functions appropriate to an extended nuclear charge distribution, and using a general local, nonderivative, decay interaction.

TL;DR: In this paper, the Wigner distribution for local spacings and the Porter-Thomas distribution for reduced widths are verified for the resonances in the even-even nuclei Ca40, Fe56, Ni58, and Ni60.