# Showing papers in "Physical Review Letters in 1983"

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TL;DR: In this article, a measure of strange attractors is introduced which offers a practical algorithm to determine their character from the time series of a single observable, and the relation of this measure to fractal dimension and information-theoretic entropy is discussed.

Abstract: A new measure of strange attractors is introduced which offers a practical algorithm to determine their character from the time series of a single observable. The relation of this new measure to fractal dimension and information-theoretic entropy is discussed.

4,323 citations

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Philips

^{1}TL;DR: The band structure of Mn-based Heusler alloys of the crystal structure (MgAgAs type) has been calculated with the augmented-spherical-wave method.

Abstract: The band structure of Mn-based Heusler alloys of the $C{1}_{b}$ crystal structure (MgAgAs type) has been calculated with the augmented-spherical-wave method. Some of these magnetic compounds show unusual electronic properties. The majority-spin electrons are metallic, whereas the minority-spin electrons are semiconducting.

3,851 citations

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TL;DR: In this article, the authors presented variational ground-state and excited-state wave functions which describe the condensation of a two-dimensional electron gas into a new state of matter.

Abstract: This Letter presents variational ground-state and excited-state wave functions which describe the condensation of a two-dimensional electron gas into a new state of matter.

3,734 citations

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TL;DR: In this article, the O(3) nonlinear sigma model of the large-spin one-dimensional Heisenberg antiferromagnet was shown to be the optimal model for weak easy-axis anisotropy.

Abstract: The continuum field theory describing the low-energy dynamics of the large-spin one-dimensional Heisenberg antiferromagnet is found to be the O(3) nonlinear sigma model. When weak easy-axis anisotropy is present, soliton solutions of the equations of motion are obtained and semiclassically quantized. Integer and half-integer spin systems are distinguished.

2,491 citations

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TL;DR: In this article, a semi-empirical model of metals and impurities (embedded atom method) was proposed to make possible a static treatment of the brittle fracture of a transition metal in the presence of hydrogen.

Abstract: A new, semiempirical model of metals and impurities (embedded atom method) makes possible a static treatment of the brittle fracture of a transition metal in the presence of hydrogen. Results indicate that hydrogen can reduce the fracture stress in nickel.

2,274 citations

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Bell Labs

^{1}TL;DR: In this article, a theory for vacuum tunneling between a real solid surface and a model probe with a locally spherical tip is presented, applicable to the recently developed "scanning tunneling microscope."

Abstract: A theory is presented for vacuum tunneling between a real solid surface and a model probe with a locally spherical tip, applicable to the recently developed "scanning tunneling microscope." Calculations for 2\ifmmode\times\else\texttimes\fi{}1 and 3\ifmmode\times\else\texttimes\fi{}1 reconstructions of Au(110) are in excellent agreement with recent experimental results, if an effective radius of curvature of 9 \AA{} is assumed for the tip.

2,091 citations

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TL;DR: In this paper, the Kohn-Sham density-functional theory was used to estimate the fundamental band gaps of semiconductors and insulators by about 40% due to derivative discontinuities of the exchange-correlation energy.

Abstract: The local-density approximation for the exchange-correlation potential understimates the fundamental band gaps of semiconductors and insulators by about 40%. It is argued here that underestimation of the gap width is also to be expected from the unknown exact potential of Kohn-Sham density-functional theory, because of derivative discontinuities of the exchange-correlation energy. The need for an energy-dependent potential in band theory is emphasized. The center of the gap, however, is predicted exactly by the Kohn-Sham band structure.

1,816 citations

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TL;DR: In this article, the Kobayashi-Maskawa matrix is expanded in powers of a small parameter equal to $sin{\ensuremath{\theta}}_{c}=0.22$ and the term of order is determined from the measured $B$ lifetime.

Abstract: The quark mixing matrix (Kobayashi-Maskawa matrix) is expanded in powers of a small parameter $\ensuremath{\lambda}$ equal to $sin{\ensuremath{\theta}}_{c}=0.22$. The term of order ${\ensuremath{\lambda}}^{2}$ is determined from the recently measured $B$ lifetime. Two remaining parameters, including the $\mathrm{CP}$-nonconservation effects, enter only the term of order ${\ensuremath{\lambda}}^{3}$ and are poorly constrained. A significant reduction in the limit on $\frac{{\ensuremath{\epsilon}}^{\ensuremath{'}}}{\ensuremath{\epsilon}}$ possible in an ongoing experiment would tightly constrain the $\mathrm{CP}$-nonconservation parameter and could rule out the hypothesis that the only source of $\mathrm{CP}$ nonconservation is the Kobayashi-Maskawa mechanism.

1,568 citations

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IBM

^{1}TL;DR: In this paper, a modified adatom model with 12 adatoms per unit cell and an inhomogeneously relaxed underlying top layer was used for Si(111) reconstruction.

Abstract: The 7× 7 reconstruction on Si(111) was observed in real space by scanning tunneling microscopy. The experiment strongly favors a modified adatom model with 12 adatoms per unit cell and an inhomogeneously relaxed underlying top layer.

1,550 citations

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TL;DR: In this article, the existence of the invisible axion for the whole allowed range of the axion decay constant was investigated, using the cosmological abundance and clustering of axions in the halo of our galaxy.

Abstract: Experiments are proposed which address the question of the existence of the "invisible" axion for the whole allowed range of the axion decay constant. These experiments exploit the coupling of the axion to the electromagnetic field, axion emission by the sum, and/or the cosmological abundance and presumed clustering of axions in the halo of our galaxy.

1,528 citations

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TL;DR: In this article, it was shown that the geometrical phase factor found by Berry in his study of the quantum adiabatic theorem is precisely the holonomy in a Hermitian line bundle.

Abstract: It is shown that the "geometrical phase factor" recently found by Berry in his study of the quantum adiabatic theorem is precisely the holonomy in a Hermitian line bundle since the adiabatic theorem naturally defines a connection in such a bundle. This not only takes the mystery out of Berry's phase factor and provides calculational simple formulas, but makes a connection between Berry's work and that of Thouless et al. This connection allows the author to use Berry's ideas to interpret the integers of Thouless et al. in terms of eigenvalue degeneracies.

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TL;DR: In this article, a translationally invariant version of Laughlin's proposed "incompressible quantum fluid" state of the two-dimensional electron gas is formulated, and extended to a hierarchy of continued-fraction Landau-level filling factors.

Abstract: With use of spherical geometry, a translationally invariant version of Laughlin's proposed "incompressible quantum fluid" state of the two-dimensional electron gas is formulated, and extended to a hierarchy of continued-fraction Landau-level filling factors $\ensuremath{
u}$. Observed anomalies at $\ensuremath{
u}=\frac{2}{5},\frac{2}{7}$ are explained by fluids deriving from a $\ensuremath{
u}=\frac{1}{3}$ parent.

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TL;DR: In this paper, the energy-band gap of an insulator is obtained from the eigenvalues of the one-particle density-functional equation for the ground state and a finite correction due to the discontinuity of the functional derivative of the exchange and correlation energy.

Abstract: The energy-band gap of an insulator is obtained from the eigenvalues of the one-particle density-functional equation for the ground state and a finite correction due to the discontinuity of the functional derivative of the exchange and correlation energy. This correction is expressed in terms of the improper self-energy and the density-functional exchange-correlation potential. It is evaluated for a two-plane-wave model including exchange only.

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DuPont

^{1}TL;DR: A model for diffusion-controlled aggregation in which growing clusters as well as individual particles are mobile has been investigated in this article, and two versions of the model in which the cluster diffusion coefficient is either size independent or inversely proportional to number of particles (mass) give very similar results.

Abstract: A model for diffusion-controlled aggregation in which growing clusters as well as individual particles are mobile has been investigated. Two versions of the model in which the cluster diffusion coefficient is either size independent or inversely proportional to number of particles (mass) give very similar results. In the limit of low concentration and large system size both models lead to structures with a fractal (Hausdorff) dimensionality of about 1.45-1.5 in two-dimensional lattice-based simulations.

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TL;DR: A lower bound for the photino mass as a function of the spin-0 fermion superpartner mass was derived as an extension of the calculation of Lee and Weinberg as mentioned in this paper.

Abstract: A lower bound for the photino mass ${m}_{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\gamma}}}$ as a function of the spin-0 fermion superpartner mass ${m}_{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{f}}$ is derived as an extension of the calculation of Lee and Weinberg. The Majorana nature of the photino induces a $p$-wave threshold for annihilation $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\gamma}}\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\gamma}}\ensuremath{\rightarrow}f\overline{f}$ into light fermions, and leads to a rather unexpected form for the bound: for $25 \mathrm{GeV}\ensuremath{\lesssim}{m}_{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{f}}\ensuremath{\lesssim}45 \mathrm{GeV}$, ${({m}_{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\gamma}}})}_{min}\ensuremath{\simeq}{m}_{\ensuremath{\tau}}=1.8$ GeV; for ${m}_{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{f}}g45$ GeV, ${({m}_{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\gamma}}})}_{min}$ increases approximately linearly with ${m}_{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{f}}$ to a value of 20 GeV when ${m}_{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{f}}=100$ GeV.

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TL;DR: In this article, a free-energy diagram is used to explain the single-phase amorphous product of pure polycrystalline Au and La thin films at temperatures of 50-80°C.

Abstract: Single-phase Au1-xLax alloys, with 0.3≲x≲0.5, have been formed through solid-state interdiffusion of pure polycrystalline Au and La thin films (100-600 A) at temperatures of 50-80°C. The reaction is driven by the large negative heat of mixing in the amorphous alloy and occurs at low temperatures by the anomalously fast diffusion of Au in La. The composition regime giving a single-phase amorphous product is explained with use of a free-energy diagram.

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TL;DR: In this article, a modele decrivant le processus de croissance de amas par agregation d'amas is introduced, which is based on the methode de Monte Carlo.

Abstract: On introduit un modele decrivant le processus de croissance d'amas par agregation d'amas. On effectue l'etude par la methode de Monte Carlo. On trouve que les amas sont invariants d'echelle

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TL;DR: In this paper, a one-dimensional Schrodinger equation in a discontinuous quasiperiodic potential is reduced to a recursion relation for transfer matrices and then to one for traces of these matrices.

Abstract: A one-dimensional Schr\"odinger equation in a discontinuous quasiperiodic potential is reduced to a recursion relation for transfer matrices and then to one for traces of these matrices. When the potential is periodic, the bandwidth goes to zero as an algebraic function of the period with a critical index which depends upon the potential strength. This critical index is also evaluated as the solution to an escape-rate problem for the recursion relations.

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TL;DR: In this paper, it was shown that the generalized Heisenberg inequality does not properly express the quantum uncertainty principle and that it is, in general, too weak to express the principle.

Abstract: The object of this Letter is to show that except in the case of canonically conjugate observables, the generalized Heisenberg inequality does not properly express the quantum uncertainty principle. It is, in general, too weak. An inequality is obtained which does express the principle.

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TL;DR: In this paper, it was shown that a fractal percolation cluster can be modeled as a self-similar structure, where all the physical properties behave as powers of the relevant length scale, i.e. independent of L, for appropriately defined quantities.

Abstract: Much of the recent renewed interest in percolation theory is related to the realization that percolation clusters are self-similar,1 and may thus be modeled by fractal structures.2 On a fractal structure, all the physical properties behave as powers of the relevant length scale, L. This behavior crosses over to a homogeneous one (i.e. independent of L, for appropriately defined quantities), on length scales larger than the percolation connectedness (or correlation) length, ξ∝|p−pc|−v. Assuming that ξ is the only important length in the problem, all other lengths should be measured in units of ξ, and thus depend on L only via the ratio L/ξ. This implies scaling. For example, above the percolation threshold (p≥pc) one has1
$$M\left( L \right) = {L^D}m\left( {L/\zeta } \right)$$
(1)
for the number of sites on the infinite incipient cluster within a volume of linear size L. The exponent D is the fractal dimensionality 2 of the cluster in the self-similar regime, and the scaling function m(x) behaves as a constant for x→0 and as m(x)∿xβ/v for x»1, so that M(L)∿LdP∞. Here, d is the Euclidean dimensionality of space, and P∞ ∿ ξ−β/v ∿ (p−pc)β is the probability per site to belong to the infinite cluster. Thus, one identifies D=d−β/v.

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TL;DR: It has been observed that the spontaneous-emission lifetime of Rydberg atoms is shortened by a large ratio when these atoms are crossing a high-Q$ superconducting cavity tuned to resonance with a millimeter-wave transition between adjacent Ryd Berg states as mentioned in this paper.

Abstract: It has been observed that the spontaneous-emission lifetime of Rydberg atoms is shortened by a large ratio when these atoms are crossing a high-$Q$ superconducting cavity tuned to resonance with a millimeter-wave transition between adjacent Rydberg states.

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TL;DR: In this paper, an order parameter for spin-glasses is defined in a clear physical way: it is a function on the interval 0-1 and it is related to the probability distribution of the overlap of the magnetization in different states of the system.

Abstract: An order parameter for spin-glasses is defined in a clear physical way: It is a function on the interval 0-1 and it is related to the probability distribution of the overlap of the magnetization in different states of the system. It is shown to coincide with the order parameter introduced by use of the broken replica-symmetry approach.

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TL;DR: In this paper, the superconducting properties of UBe13 were investigated and it was shown that UBe 13 is superconducted below 0.85 K. Highly anomalous low-temperature electronic properties in both the normal and super-conducting states result in an enormous electronic specific heat coefficient γ=1.1J/mole K2 and a corresponding magnetic susceptibility X = 1.5×10-2 emu/moles.

Abstract: Electrical-resistivity, magnetic-susceptibility, and specific-heat data reveal that UBe13 is superconducting below 0.85 K. Highly anomalous low-temperature electronic properties in both the normal and superconducting states result in an enormous electronic specific-heat coefficient γ=1.1J/mole K2 and a corresponding magnetic susceptibility X =1.5×10-2 emu/mole. The superconducting state appears to be extremely stable with an initial slope of the temperature derivative of the critical field(∂H c2/∂T) Tc =-257kOe/K.

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TL;DR: In this paper, a new quantum field-theoretical technique is developed and used to explore the relationship between evenspace-time-dimensional axial anomalies and background-field-induced fermion numbers and Euler-Heisenberg effective actions in odd-dimensional space-times.

Abstract: A new quantum field-theoretical technique is developed and used to explore the relationship between even-space-time-dimensional axial anomalies and background-field-induced fermion numbers and Euler-Heisenberg effective actions in odd-dimensional space-times

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TL;DR: By adding the trivial term $\ensuremath{-}d{t}^{2}$ one can convert the four-dimensional (positive-definite) Newman-Unti-Tamburino line element into a static solution of the five-dimensional vacuum Einstein equations.

Abstract: By adding the trivial term $\ensuremath{-}d{t}^{2}$ one can convert the four-dimensional (positive-definite) Newman-Unti-Tamburino line element into a static solution of the five-dimensional vacuum Einstein equations. Interpreted $\stackrel{`}{a}\mathrm{la}$ Kaluza and Klein, the solution describes a monopole with a charge-to-mass ratio of $\sqrt{2}$ in rationalized Planck units. Although it is a perfectly regular five-geometry it appears singular from a four-dimensional perspective.

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TL;DR: In this paper, the spin and statistics of solitons in the (2 + 1)- and (3 + 1) nonlinear sigma models are considered. And for the 3 + 1 dimensions, the usual spin-statistics relation is demonstrated, using the linking-number interpretation of the Hopf invariant and the use of suspension.

Abstract: The spin and statistics of solitons in the (2 + 1)- and (3 + 1)-dimensional nonlinear sigma models is considered. For the (2 + 1)-dimensional case, there is the possibility of fractional spin and exotic statistics; for 3 + 1 dimensions, the usual spin-statistics relation is demonstrated. The linking-number interpretation of the Hopf invariant and the use of suspension considerably simplify the analysis.

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TL;DR: In this article, a special tight-binding model is solved exactly by a renormalization group whose fixed points determine the scaling properties of both the energy spectrum and certain features of the eigenstates.

Abstract: Recent theories of scaling in quasiperiodic dynamical systems are applied to the behavior of a particle in an almost periodic potential. A special tight-binding model is solved exactly by a renormalization group whose fixed points determine the scaling properties of both the energy spectrum and certain features of the eigenstates. Similar results are found empirically for Harper's equation. In addition to ordinary extended and localized states, "critical" states are found which are neither extended nor localized according to conventional criteria.

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TL;DR: In this paper, the strong forces binding quarks and leptons induce flavor-diagonal contact interactions, which have significant effects at reaction energies well below 1.5$ TeV for both electrons and light quarks.

Abstract: If quarks and leptons are composite at the energy scale $\ensuremath{\Lambda}$, the strong forces binding their constituents induce flavor-diagonal contact interactions, which have significant effects at reaction energies well below $\ensuremath{\Lambda}$. Consideration of their effect on Bhabha scattering produces a new, stronger bound on the scale of electron compositeness: $\ensuremath{\Lambda}g750$ GeV. Collider experiments now being planned will be sensitive to $\ensuremath{\Lambda}\ensuremath{\sim}1\ensuremath{-}5$ TeV for both electrons and light quarks.

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TL;DR: In this paper, a very clean signature for the production of neutrinos is pointed out and detailed predictions regarding the production and decay rates of hadronic jets are presented, with the branching ratio \ensuremath{\sim}3%.

Abstract: A possibility of a very clean signature for the production of ${{W}_{R}}^{\ifmmode\pm\else\textpm\fi{}}$ is pointed out. If the right-handed neutrino is lighter than ${{W}_{R}}^{\ifmmode\pm\else\textpm\fi{}}$, left-right symmetric gauge theory predicts the decay ${{W}_{R}}^{+}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{+}+2$ hadronic jets, with the branching ratio \ensuremath{\sim}3%. The lack of neutrinos in the final state and the absence of a sizable background make ${{W}_{R}}^{\ifmmode\pm\else\textpm\fi{}}$ rather easy to detect (if it exists). Detailed predictions regarding the production and decay rates of ${{W}_{R}}^{+}$ are presented.

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TL;DR: In this paper, the number of photons emitted in a short time interval by a single atom in the process of resonance fluorescence is measured, and it is shown that the probability distribution of this number is sub-Poissonian.

Abstract: The number of photons emitted in a short time interval by a single atom in the process of resonance fluorescence is measured, and it is shown that the probability distribution of this number is sub-Poissonian.