Showing papers in "Physical Review Letters in 1963"
CERN1
TL;DR: In this article, an analysis of leptonic decays based on unitary symmetry for strong interactions and the V-A theory for weak interactions is presented, and an explanation for the observed predominance of the LAMBDA yields + e/sup -/ + nu decay over the lamBDA /sup −/ yields n + e /sup + n decay.
Abstract: An analysis of leptonic decays based on unitary symmetry for strong interactions (eightfold way) and the V-A theory for weak interactions is presented. An explanation for the observed predominance of the LAMBDA yields + e/sup -/ + nu decay over the LAMBDA /sup -/ yields n + e/sup -/ + nu decay is obtained. Branching ratios predicted for electron modes with DELTA S, 1 are presented; the ratios for the above decays agree well with experimental results. (D.C.W.)
3,957 citations
2,529 citations
2,236 citations
TL;DR: In this article, a simple prediction for the temperature dependence of the d-c supercurrent is shown to follow from the theory of the thermodynamic Green's function, which allows generalization to superconductors with strong electron-phonon coupling.
Abstract: Josephson's calculations showed that for two superconductors separated by an oxide there may exist an osciliating supercurrent of frequency 2e V/h (V is applied voltage) and a possible d-c supercurrent at zero voltage. The calculations are reproduced by the method of the thermodynamic Green's function that allows generalization to superconductors with strong electron-phonon coupling. A simple prediction for the temperature dependence of the d-c supercurrent is shown to follow from the theory. (D.C.W.)
1,580 citations
TL;DR: In this article, the equation of state and pair distribution for the Percus- Yevick integral equation for the radiai distribution function of a classical fluid are obtained in closed form for the prototype of interacting hard spheres.
Abstract: ABS>The equation of state and the pair distribution for the Percus- Yevick integral equation for the radiai distribution function of a classical fluid are obtained in closed form for the prototype of interacting hard spheres. (D.C.W.)
1,420 citations
IBM1
TL;DR: In this paper, the wave function for the electrons is investigated when a set of narrow bands (valence states) has its energies within a wide band (conduction states), where the valence states are linear combinations of localized states which are attached to each lattice site.
Abstract: The wave function for the electrons is investigated when a set of narrow bands (valence states) has its energies within a wide band (conduction states). The valence states are linear combinations of localized states which are attached to each lattice site. The intra-atomic Coulomb and exchange integrals for the localized states are much larger than the bandwidths of the valence states. Some of the narrow bands are neither completely empty nor completely filled. The wave function is therefore expected to be correlated, because it is disadvantageous for the electrons to crowd into the same lattice site, or take up some configuration contrary to Hund's rule. This correlation is important in trasition metals, where it is considered to be the cause of ferromagnetism. The correlated wave function is obtained by applying to the uncorrelated antisymmetrized product of Bloch functions an operator which provides each configuration of localized valence states with an appropriate amplitude and phase factor. The procedure is worked out in detail for the case of few particles (electrons or holes) in the narrow bands with the help of a diagram analysis. The localized orbits of different lattice sites do not have to be orthogonal to on another, and the computational rules are actually simplified thereby. The example of a twofold degenerate band such as the upper part of the $3d$ band in Ni is treated, and the conditions for the occurrence of ferromagnetism are stated in the case of few $3d$ holes per lattice site.
1,198 citations
TL;DR: In this article, a tunneling crossing of low resistance (5 to 20 OMEGA with a crossing area of 1.5 x 10/sup -4/ cm/sup −2/) was fabricated.
Abstract: Tunneling crossings of low resistance (5 to 20 OMEGA with a crossing area of 1.5 x 10/sup -4/ cm/sup -2/) were fabricated. Each of these exhibited zero-voltage currents predicted by Josephson and attributed, in effect, to the tunneling of Cooper pairs. New effects are summarized from experiments on the Al/ Al2/sub 2//sub 3//Sn samples. (R.E.U.)
780 citations
TL;DR: In this paper, a new technique for studying asymptotic questions in general relativity is presented, where points at infinity are introduced which constitute a null hypersurface boundary to space-time.
Abstract: : A new technique for studying asymptotic questions in general relativity is presented. Points at infinity are introduced which constitute a null hypersurface boundary to space-time. This is studied from the point of view of its conformal structure and some new light is shed on the following questions: (1) asymptotic flatness, (2) gravitational radiation fields, (3) peeling off property of the Riemann tensor, (4) total energy-momentum with integral conservation laws, (5) characteristic initial value problem and (6) Bondi-Metzner-Sachs asymptotic symmetry group. (Author)
637 citations
531 citations
TL;DR: In this article, an anomalous d-c tunneling current at or near zero voltage was observed in very thin tin oxide barriers between superconducting Sn and Pb that cannot be ascribed to superconducted leakage paths across the barrier and that behaves in several respects like the Josephson current.
Abstract: An anomalous d-c tunneling current at or near zero voltage was observed in very thin tin oxide barriers between superconducting Sn and Pb that cannot be ascribed to superconducting leakage paths across the barrier and that behaves in several respects like the Josephson current. (C.E.S.)
503 citations
TL;DR: In this paper, the authors describe the dynamics and coupling of sound by streaming electrons in the ionosphere, analogous to phonon excitation by Hall currents, but the dynamics are somewhat different and the coupling is provided by ions that communicate with the neutral gas by collisions and with the electrons by macroscopic electrostatic fields.
Abstract: Excitation of sound by streaming electrons in the ionosphere is analogous to phonon excitation by Hall currents, but the dynamics and coupling are somewhat different. The coupling is provided by ions that communicate with the neutral gas by collisions and with the electrons by macroscopic electrostatic fields. The sharp dependence of electron mobility on anale, near the 90 un. Concent 85% inclination to the magnetic field, provides a necessary tunability of the electronic generator to the acoustic load. The wave fronts are field aligned, because the electrons can short out all electric fields. (C.E.S.)
TL;DR: In this paper, the authors used the relationship and assumptions used in estimating the size of a cosmic air shower recorded at the MIT Volcano Ranch station and estimated the total number of particles produced as 5 x 10/sup 10/, and the total energy of the primary particle was estimated as 1.0 x 10 /sup 20/ ev.
Abstract: Relations and assumptions used in estimating the size of a cosmic air shower recorded at the MIT Volcano Ranch station are discussed. The total number of particles produced is estimated as 5 x 10/sup 10/, and the total energy of the primary particle is estimated as 1.0 x 10/sup 20/ ev, indicating its origin outside our galaxy. (D.C.W.)
TL;DR: In this article, it was shown that one may expect to obtain on the order of several thousand collimated high-energy scattered pho-tons, and that these quanta retain the polarization of the original beam of optical photons by using existing laser systems and electron accelerators.
Abstract: It was shown that one may expect to obtain on the order of several thousand collimated high-energy scattered pho-tons, and that these quanta retain the polarization of the original beam of optical photons by using existing laser systems and electron accelerators. The total number of scatterings were independent of the duration of the light pulse and depended upon the total light energy per unit area of the beam. (C.E.S.)
TL;DR: In this article, it was shown that the singlet state giving rise to the fluorescence is produced by a bimolecular annihilation of triplet excitons generated directly by the laser light.
Abstract: Delayed fluorescence was detected in laser-induced fluorescence in anthracene single crystals after the laser pulse ended. The rate of decay of this fluorescence and other experimental observations was explained by assuming that the singlet state giving rise to the fluorescence is produced by a bimolecular annihilation of triplet excitons generated directly by the laser light. The lifetime and the bimolecular interaction rate constant of the triplet excitons were found to be 10 msec and 10/sup -11/ cm/sup 3/ sec-/sup 1/, respectively. (C.E.S.)
TL;DR: In this article, a new model for the band structure of n-Sn is proposed which is compatible with the experimental results reported on this material and particularly with the measurements of magnetoresistance and the pressure dependence of the conductivity (o) and Hall coefficient (R) which have been in relatively poor agreement with models previously suggested.
Abstract: In this Letter a new model for the band structure of n-Sn is proposed which is compatible with the experimental results reported on this material and particularly with the measurements of magnetoresistance and the pressure dependence of the conductivity (o) and Hall coefficient (R) which have been in relatively poor agreement with models previously suggested. Theoretical calculations of Herman, ' and of Liu and Bassani, ' predict the lowest conduction band to be at the center of the Brillouin zone with I', (I', ' single group representation) symmetry, and the highest valence band to have I', + (I"»' single group representation) symmetry. This is in agreement with magnetoresistance measurements' near 77 K and with oscillatory magnetoresistance data' at and below 4'K, both of which show no measurable anisotropy. However, several unrelated measurements require the presence of conduction-band minima of (111) symmetry. Magnetoresistance measurements near 200 K by
TL;DR: In this article, a classification of the states that produce the autoionizing lines observed in spectra of He is considered, and properties of these states are discussed. (D.C.W.)
Abstract: Classification of the states that produce the autoionizing lines recently observed in spectra of He is considered. Properties of the states are discussed. (D.C.W.)
TL;DR: In this article, the mean excitational potential values required to obtain the proper masses and momentum balance in the processes were estimated to be 321 plus or minus 8 ev. The following masses were derived: SIGMA /sup +/, 1189.15 Mev; K/sup -/, 493.7 Mev.
Abstract: Ranges of the particles in SIGMA /sup +/ yields p + pi /sup o/, SIGMA /sup +/ yields n + pi/sup +/ K/sup -/ + p yields SIGMA /saup +/ + pi / sup -/, K/sup -/ + p yields SIGMA /sup +/ + pi /sup -/, K/sup -/ + p yields SIGMA /sup -/ + pi /sup +/ in emulsion were measured. From the mean excitational potential values required to obtain the proper masses and momentum balance in the processes, the best value of this potential was estimated to be 321 plus or minus 8 ev. The following masses were derived: SIGMA /sup +/, 1189.35 plus or minus 0.15 Mev; K/sup -/, 493.7 plus or minus 0.3 Mev; SIGMA /sup -/, 1197.6 plus or minus 0.5 Mev; and SIGMA /sup o/, 1193.2 plus or minus 0.7 Mev. A hyperon ( SIGMA /sup -/) range of 708.9 plus or minus 1.5 mu was observed in disagreement with the 684 plus or minus 5 mu expected if the stopping cross sections of positive and negative particles were equal. (D.C.W.)
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TL;DR: In this article, a theoretical determination of the tunneling characteristic of superconducting metals is presented, and experimental and theoretical curves for the density of states show good agreement with the structure observed in the I-V characteristic.
Abstract: Results of a theoretical determination of the tunneling characteristic, that agree well with structure observed in the I-V characteristic of superconducting metals, are presented. Experimental and theoretical curves for the density of states show good agreement. (D.C.W.)
TL;DR: In this paper, the elastic differential cross sections for proton interactions with mesons (pi /sup +/) and ( pi /sup -/) and protons in the momentum region 7-20 Bev/c were reported.
Abstract: Elastic differential cross sections for proton interactions with mesons( pi /sup +/) and ( pi /sup -/) and protons in the momentum region 7-20 Bev/c were reported. The square of the four-momentum transfer was approximates 0.02--0.6 (Bev/c)/sup 2/. Values of the total elastic cross sections were also obtained. Evidence was found for a real amplitude or a sizeable spin dependence in the p + p case and for a real amplitude for pi /sup +/ + p. (C.E.S.)
TL;DR: In this article, the Fermi level at the interface of metal-semiconductor interfaces was determined by surface states, independent of the metal, and the relationship between the energy at interface and the band gap was investigated.
Abstract: There have been several recent reports of barrier height studies on metal-semiconductor interfaces. Metals of widely different work functions evaporated onto Si and GaAs surfaces indicated that in each case the energy difference
between the semiconductor conduction band edge
and Fermi level at the interface,φ_(Bn), was essentially
independent of the metal, which indicates
that the Fermi level is fixed by surface
states. In the present work barrier height measurements
have been made on a number of zinc-blende semiconductors to determine (a) if the barriers are in all cases determined by surface states, and (b) the relation between the Fermi
energy at the interface and the band gap E_g.
TL;DR: In this paper, the dependence of a laser's power output and exact oscillation frequency dependence on the saturation behavior of the atomic transition was used to study the transition Two He- Ne lasers containing isotopically enriched samples of Ne20 and Ne22/ were used from frequency considerations, the isotope shift was determined to be 261 plus or minus 3 Mc/sec at 1 mm Ne and 10 mm He partial pressures Extrapolation from a plot of the saturation parameters is total He-Ne pressure gave limits for the parameters of 108 sec-1
Abstract: The dependence of a laser's power output and exact oscillation frequency dependence on the saturation behavior of the atomic transition was used to study the transition Two He- Ne lasers containing isotopically enriched samples of Ne20 and Ne22/ were used From frequency considerations, the isotope shift was determined to be 261 plus or minus 3 Mc/sec at 01 mm Ne and 10 mm He partial pressures Extrapolation from a plot of the saturation parameters is total He-Ne pressure gave limits for the parameters of 108 sec-1
TL;DR: In this article, the range of 40-kev Kr/sup 85/ ions in amorphous Al/sub 2/O/sub 3/ and in polycrystalline Al was measured.
Abstract: The range of 40-kev Kr/sup 85/ ions in amorphous Al/sub 2/O/sub 3/ and in polycrystalline Al was measured. The range distribution in the polycrystalline Al showed an exponential behavior due to the crystalline structure. The existence of a channeling process was strongly suggested by the striking qualitative resemblance between experiment and calculation. (C.E.S.)