Showing papers in "Physical Review Letters in 1981"
Abstract: A model for random aggregates is studied by computer simulation The model is applicable to a metal-particle aggregation process whose correlations have been measured previously Density correlations within the model aggregates fall off with distance with a fractional power law, like those of the metal aggregates The radius of gyration of the model aggregates has power-law behavior The model is a limit of a model of dendritic growth
4,248 citations
TL;DR: In this article, the linear polarization correlation of the photons emitted in a radiative atomic cascade of calcium was measured, in excellent agreement with the quantum mechanical predictions, strongly violate the generalized Bell's inequalities, and rule out the whole class of realistic local theories.
Abstract: We have measured the linear polarization correlation of the photons emitted in a radiative atomic cascade of calcium A high-efficiency source provided an improved statistical accuracy and an ability to perform new tests Our results, in excellent agreement with the quantum mechanical predictions, strongly violate the generalized Bell's inequalities, and rule out the whole class of realistic local theories No significant change in results was observed with source-polarizer separations of up to 65 m
1,952 citations
TL;DR: In this article, a quantum system which can tunnel out of a metastable state and whose interaction with its environment is adequately described in the classically accessible region by a phenomenological friction coefficient was considered.
Abstract: A quantum system which can tunnel, at $T=0$, out of a metastable state and whose interaction with its environment is adequately described in the classically accessible region by a phenomenological friction coefficient $\ensuremath{\eta}$, is considered. By only assuming that the environment response is linear, it is found that dissipation multiplies the tunneling probability by the factor $\mathrm{exp}[\ensuremath{-}\frac{A\ensuremath{\eta}{(\ensuremath{\Delta}q)}^{2}}{\ensuremath{\hbar}}]$, where $\ensuremath{\Delta}q$ is the "distance under the barrier" and $A$ is a numerical factor which is generally of order unity.
1,686 citations
TL;DR: In this paper, it was shown that the same arguments which lead to black hole evaporation also predict that a thermal spectrum of sound waves should be given out from the sonic horizon in transsonic fluid flow.
Abstract: It is shown that the same arguments which lead to black-hole evaporation also predict that a thermal spectrum of sound waves should be given out from the sonic horizon in transsonic fluid flow.
1,492 citations
TL;DR: In this paper, a theory of the cholesteric blue phase is presented, assuming a first-order Cholesteric-isotropic transition, and it is shown that the planar helix structure becomes unstable at temperatures near the transition point.
Abstract: We present a theory of the cholesteric blue phase, assuming a first-order cholesteric-isotropic transition. We show, on the basis of the Oseen-Frank elasticity equations, that the planar helix structure, generally associated with the cholesteric phase, becomes unstable at temperatures near the transition point. It transforms into a phase characterized by a network of disclination lines.
1,286 citations
TL;DR: The effect of thermal and structural disorder on the electronic structure of hydrogenated amorphous silicon is investigated by measurement of the shape of the optical absorption edge as a function of temperature and thermal evolution of hydrogen as discussed by the authors.
Abstract: The effect of thermal and structural disorder on the electronic structure of hydrogenated amorphous silicon is investigated by measurement of the shape of the optical absorption edge as a function of temperature and thermal evolution of hydrogen. The data are consistent with the idea that the thermal and structural disorder are additive, and suggest that the disorder, rather than the hydrogen content, is the fundamental determining factor in the optical band gap.
974 citations
TL;DR: The dispersion equation of injected surface-plasma waves that propagate on thin metal films has been solved as a function of the film thickness, and splitting of the modes into two branches is observed.
Abstract: The dispersion equation of injected surface-plasma waves that propagate on thin metal films has been solved as a function of the film thickness, and splitting of the modes into two branches is observed. For one branch the imaginary part of the propagation constant goes to zero as the thickness of the metal decreases. Reflectivity calculations agree with this result, which predicts that one can obtain propagation distances that are more than 1 order of magnitude larger than observed before.
881 citations
TL;DR: In this paper, a universal description of low-energy properties of one-dimensional quantum fluids, based on a harmonic theory of long-wavelength density fluctuations with use of renormalized parameters, is outlined.
Abstract: A universal description of the low-energy properties of one-dimensional quantum fluids, based on a harmonic theory of long-wavelength density fluctuations with use of renormalized parameters, is outlined. The structure of long-distance correlations of a spinless fluid is obtained, showing the essential similarity of one-dimensional Bose and Fermi fluids. The results are illustrated by application to the one-dimensional Bose fluid with $\ensuremath{\delta}$-function interaction.
834 citations
TL;DR: The radiative properties of an atom in a cavity differ fundamentally from the atom's radiative property in free space as mentioned in this paper. But the cavity causes slight shifts in the energies of the atom, analogous to radiative shifts.
Abstract: The radiative properties of an atom in a cavity differ fundamentally from the atom's radiative properties in free space. Spontaneous emission is inhibited if the cavity has characteristic dimensions which are small compared to the radiation wavelength, and enhanced if the cavity is resonant. The cavity causes slight shifts in the energies of the atom, analogous to radiative shifts. Experiments are proposed for observing these effects.
830 citations
TL;DR: The phase diagram of the infinite-range model of spin-glasses exhibits two mixed phases as mentioned in this paper, where ferromagnetism and spin-glass order coexist, due to freezing of the transverse degrees of freedom.
Abstract: The phase diagram of the infinite-range model of spin-glasses exhibits two mixed phases. In these mixed phases, ferromagnetism and spin-glass order coexist, due to freezing of the transverse degrees of freedom or replica symmetry breaking. This may help to interpret a number of recent experimental findings, e.g., in $\mathrm{Au}\mathrm{Fe}$.
731 citations
TL;DR: The existence of magic numbers for atomic microclusters has been found experimentally for the first time as mentioned in this paper, and the magic numbers manifest themselves in the mass spectra of free xenon clusters, nucleated in the gas phase.
Abstract: The existence of magic numbers for atomic microclusters has been found experimentally for the first time. The magic numbers ${n}^{*}$ manifest themselves in the mass spectra of free xenon clusters, nucleated in the gas phase. The observed numbers ${n}^{*}=13, 55, \mathrm{and} 147$ coincide with the numbers of spheres required for complete-shell icosahedra. The appearance of further magic numbers (19, 25, 71, and 87) is only partially explained by previous calculations.
TL;DR: In this article, the authors provide evidence for a universal relationship between metallic binding energies and lattice parameters, and obtain binding energies as a function of atomic separation for bimetallic interfaces and bulk metals.
Abstract: We provide evidence for a universal relationship between metallic binding energies and lattice parameters. By a simple scaling of a universal relationship, one can obtain binding energies as a function of atomic separation for bimetallic interfaces and bulk metals.
TL;DR: In this article, a method is proposed to calculate quantum numbers on solitons in quantum field theory, and the method is checked on previously known examples and, in a special model, by other methods.
Abstract: A method is proposed to calculate quantum numbers on solitons in quantum field theory. The method is checked on previously known examples and, in a special model, by other methods. It is found, for example, that the fermion number on kinks in one dimension or on magnetic monopoles in three dimensions is, in general, a transcendental function of the coupling constant of the theories.
TL;DR: In this article, the distribution function of the local order parameter in finite blocks of size is studied for Ising models for dimensionalities $d=2, 3, \mathrm{and} 4$ by Monte Carlo methods.
Abstract: The distribution function ${P}_{L}(s)$ of the local order parameter $s$ in finite blocks of size ${L}^{d}$ is studied for Ising models for dimensionalities $d=2, 3, \mathrm{and} 4$ by Monte Carlo methods. A real-space renormalization group based on phenomenological scaling yields fairly accurate results for rather small $L$ (e.g., the standard exponents $\ensuremath{\beta}$ and $\ensuremath{
u}$ for $d=3$ are found as $\frac{2\ensuremath{\beta}}{\ensuremath{
u}}=1.03\ifmmode\pm\else\textpm\fi{}0.01$, $\frac{1}{\ensuremath{
u}}=1.60\ifmmode\pm\else\textpm\fi{}0.05$). The method can easily be generalized to arbitrary Hamiltonians, including spin dimensionalities $ng1$.
TL;DR: In this article, the scaling behavior of the conductance of disordered systems is determined and the localization length for disordered system is calculated with a new recursive method, based on the assumptions about the $\ensuremath{\beta}$ function made in recent analytical work.
Abstract: The localization length for disordered systems is calculated with a new recursive method. The scaling behavior of the conductance is determined. The assumptions about the $\ensuremath{\beta}$ function made in recent analytical work are confirmed. Only localized states are found for two dimensions. In three dimensions there is an Anderson transition at a critical disorder of ${W}_{c}=16\ifmmode\pm\else\textpm\fi{}0.5$ with critical exponents for the conductivity and the localization length of $s=\ensuremath{
u}=1.2\ifmmode\pm\else\textpm\fi{}0.3$, respectively.
IBM1
TL;DR: In this paper, the authors examined several qualitatively different structural models for the Si(111)-(2/ifmmode/times/else\texttimes\fi{}1) surface.
Abstract: Several qualitatively different structural models have been examined in a critical evaluation of spectroscopic and other data for the Si(111)-(2\ifmmode\times\else\texttimes\fi{}1) surface. Within the one-electron theory, only a novel $\ensuremath{\pi}$-bonded chain model with a covalent surface, and not the generally accepted buckled model with an ionic surface, is consistent with the data.
IBM1
TL;DR: In this article, a systematic study of mixed stacked organic charge transfer compounds was conducted and it was shown that these materials are either neutral or ionic and that they range from being near the neutral-ionic boundary to being far away.
Abstract: A systematic study of mixed stacked organic charge-transfer compounds shows that these materials are either neutral or ionic and that they range from being near the neutral-ionic boundary to being far away. Under pressure, several neutral compounds near this boundary are found to undergo a reversible phase transition to an ionic ground state. This is the first observation of a neutral-to-ionic transition in any kind of material.
TL;DR: In this paper, Monte Carlo data and duality arguments are applied to a lattice model to show that a three-dimensional type-II superconductor should have a transition asymptotically equivalent to that of a superfluid with reversed temperature axis, and not a first-order transition.
Abstract: Monte Carlo data and duality arguments, applied to a lattice model, are presented which indicate that a three-dimensional type-II superconductor should have a transition asymptotically equivalent to that of a superfluid with reversed temperature axis, and not a first-order transition. Results may apply to the nematic---smectic-$A$ transition.
TL;DR: In this article, a general theory of metastability is constructed in which these formulas are true for temperatures, respectively, below and above the saddle point of a system rendered unstable by both quantum tunneling and thermodynamic fluctuation.
Abstract: Consider a system rendered unstable by both quantum tunneling and thermodynamic fluctuation. The tunneling rate $\ensuremath{\Gamma}$, at temperature ${\ensuremath{\beta}}^{\ensuremath{-}1}$, is related to the free energy $F$ by $\ensuremath{\Gamma}=(\frac{2}{\ensuremath{\hbar}})\mathrm{Im}F$. However, the classical escape rate is $\ensuremath{\Gamma}=(\frac{\ensuremath{\omega}\ensuremath{\beta}}{\ensuremath{\pi}})\mathrm{Im}F$, $\ensuremath{-}{\ensuremath{\omega}}^{2}$ being the negative eigenvalue at the saddle point. A general theory of metastability is constructed in which these formulas are true for temperatures, respectively, below and above $\frac{\ensuremath{\omega}\ensuremath{\hbar}}{2\ensuremath{\pi}}$ with a narrow transition region of $O({\ensuremath{\hbar}}^{\frac{3}{2}})$.
TL;DR: In this article, the conduction and valence-band width of amorphous silicon hydride is inferred from time-of-flight measurements of the temperature dependence of the electron and hole drift mobilities, and a multiple-trapping model of dispersive transport.
Abstract: The width of the conduction- and valence-band tails in amorphous silicon hydride are inferred from time-of-flight measurements of the temperature dependence of the electron and hole drift mobilities, and a multiple-trapping model of dispersive transport.
TL;DR: Second harmonic generation at a silver-air interface was enhanced due to surface roughness by a factor of 10{sup 4} as mentioned in this paper, which is believed to be responsible for the effect An unusually broad luminescence background extending far beyond the antiStokes side of the second harmonic was also observed
Abstract: Second harmonic generation at a silver-air interface was enhanced due to surface roughness by a factor of 10{sup 4} The local field enhancement is believed to be responsible for the effect An unusually broad luminescence background extending far beyond the antiStokes side of the second harmonic was also observed
TL;DR: In this paper, the conductance for a two-dimensional tight-binding model with on-site disorder is calculated numerically with use of the Kubo formula. And the magnetoresistance is found to be negative in both the logarithmic and exponential localization regimes.
Abstract: The conductance for a two-dimensional tight-binding model with on-site disorder is calculated numerically with use of the Kubo formula. For weak disorder logarithmic localization is observed, in agreement with the scaling theory. The magnetoresistance is found to be negative in both the logarithmic and exponential localization regimes. Results for a model with random complex hopping matrix elements are also presented.
TL;DR: In this article, reduced quantum fluctuations or squeezing are present in both the atomic observables and the radiation field produced by a two-level atom undergoing resonance fluorescence, and it is shown that reduced quantum fluctuation or squeezing is present in the two level atom.
Abstract: We demonstrate that reduced quantum fluctuations or squeezing are present in both the atomic observables and the radiation field produced by a two-level atom undergoing resonance fluorescence.
TL;DR: In this article, the exponents of the Lee-Yang edge singularity of the Ising model in two and three dimensions were obtained from the exact solution in zero and one dimensions.
Abstract: The exponents for large branched dilute polymers (which are also connected with the exponents of the lattice animals) are related in $D$ dimensions to the exponents of the Lee-Yang edge singularity of the Ising model in $D\ensuremath{-}2$ dimensions. From the exact solution of the Ising model in zero and one dimension, one gets the polymer exponents in two and three dimensions, $\ensuremath{\theta}(D=2)=1$ and $\ensuremath{\theta}(D=3)=\frac{3}{2}$.
TL;DR: In this article, a driven anharmonic oscillator is described which exhibits period doubling and chaotic behavior, and the measured behavior of the oscillator under successive period doublings is in quantitative agreement with a recent theory which describes the behavior of nonlinear systems.
Abstract: A driven anharmonic oscillator is described which exhibits period doubling and chaotic behavior. The measured behavior of the oscillator under successive period doublings is in quantitative agreement with a recent theory which describes the behavior of nonlinear systems. Both the scalirg and the convergence rate predicted by the theory are verified by the experiment. The oscillator also exhibits period tripling and quintupling.
TL;DR: It was shown in this paper that vacuum strings produced in the early universe at the grand unification phase transition can generate density fluctuations sufficient to explain the galaxy formation, and it was shown that these fluctuations can be used to explain galaxy formation.
Abstract: It is shown that vacuum strings produced in the early universe at the grand unification phase transition can generate density fluctuations sufficient to explain the galaxy formation.
TL;DR: In this paper, direct numerical simulations of three-dimensional magnetohydrodynamic turbulence with kinetic and magnetic Reynolds numbers up to 100 are presented, showing that small-scale helical driving produces strong large-scale nearly force-free magnetic fields.
Abstract: Direct numerical simulations of three-dimensional magnetohydrodynamic turbulence with kinetic and magnetic Reynolds numbers up to 100 are presented. Spatially intermittent magnetic fields are observed in a flow with nonhelical driving. Small-scale helical driving produces strong large-scale nearly force-free magnetic fields.
TL;DR: In this article, the multiple-trapping mechanism was used to explain photo-induced optical absorption transients in a unified way with the multiple trapping mechanism, and transient photoconductivity provided a spectroscopy of the density of localized states.
Abstract: Measurements of transient photoinduced optical absorption in $a$-${\mathrm{As}}_{2}$${\mathrm{Se}}_{3}$ show that carriers thermalize within a distribution of localized states in the band gap. Photocurrent as well as photoinduced optical absorption transients are explained in a unified way with the multiple-trapping mechanism. Under such circumstances, transient photoconductivity provides a spectroscopy of the density of localized states.
TL;DR: In this paper, the presence of unitary group generators in the time evolution of $N$-level quantum systems is shown to suggest a class of new nonlinear constants of motion, and to permit the description of the evolution in terms of the rotations of a real coherence vector.
Abstract: The presence of unitary group generators in the time evolution of $N$-level quantum systems is shown to suggest a class of new nonlinear constants of motion, and to permit the description of the evolution in terms of the rotations of a real coherence vector.