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Showing papers by "University of California, Santa Barbara published in 1983"


Book ChapterDOI
01 Jan 1983
TL;DR: Automation of the way the authors pay for goods and services is already underway, as can be seen by the variety and growth of electronic banking services available to consumers.
Abstract: Automation of the way we pay for goods and services is already underway, as can be seen by the variety and growth of electronic banking services available to consumers. The ultimate structure of the new electronic payments system may have a substantial impact on personal privacy as well as on the nature and extent of criminal use of payments. Ideally a new payments system should address both of these seemingly conflicting sets of concerns.

3,308 citations


Journal ArticleDOI
TL;DR: In this article, the authors identify a new cosmological problem for models which solve the strong CP puzzle with an invisible axion, unrelated to the domain wall problem, and identify the energy density stored in the oscillations of the classical axion field does not dissipate rapidly; it exceeds the critical density needed to close the universe unless fa ⩽ 1012GeV wherefa is the axion decay constant.

2,557 citations


Journal ArticleDOI
TL;DR: In this article, the ground state amplitude for a three-manifold is given by a path integral over all compact positive-definite four-geometries which have the three-geometry as a boundary.
Abstract: The quantum state of a spatially closed universe can be described by a wave function which is a functional on the geometries of compact three-manifolds and on the values of the matter fields on these manifolds. The wave function obeys the Wheeler-DeWitt second-order functional differential equation. We put forward a proposal for the wave function of the "ground state" or state of minimum excitation: the ground-state amplitude for a three-geometry is given by a path integral over all compact positive-definite four-geometries which have the three-geometry as a boundary. The requirement that the Hamiltonian be Hermitian then defines the boundary conditions for the Wheeler-DeWitt equation and the spectrum of possible excited states. To illustrate the above, we calculate the ground and excited states in a simple minisuperspace model in which the scale factor is the only gravitational degree of freedom, a conformally invariant scalar field is the only matter degree of freedom and $\ensuremath{\Lambda}g0$. The ground state corresponds to de Sitter space in the classical limit. There are excited states which represent universes which expand from zero volume, reach a maximum size, and then recollapse but which have a finite (though very small) probability of tunneling through a potential barrier to a de Sitter-type state of continual expansion. The path-integral approach allows us to handle situations in which the topology of the three-manifold changes. We estimate the probability that the ground state in our minisuperspace model contains more than one connected component of the spacelike surface.

2,445 citations


Journal ArticleDOI
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


Journal ArticleDOI
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.

1,365 citations


Journal ArticleDOI
TL;DR: In this paper, the authors study both numerically and analytically the time development of a system of particles and antiparticles moving diffusively and annihilating irreversibly.
Abstract: We study both numerically and analytically the time development of a system of particles and antiparticles moving diffusively and annihilating irreversibly The asymptotic behavior is found to depend dramatically on whether the initial fluctuations are localized or entirely random Physical examples of each kind are identified

547 citations


Journal ArticleDOI
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.

545 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that the configuration space of the classical, bosonic Weinberg-Salam theory has a non-contractible loop, which probably implies that there is an unstable, static, finite-energy solution of the field equations.
Abstract: We show that the configuration space of the classical, bosonic Weinberg-Salam theory has a non-contractible loop. This probably implies that there is an unstable, static, finite-energy solution of the field equations. Its energy is the height of the barrier for tunneling between "topologically distinct" vacuums. We establish an upper bound on this energy of order 10 TeV.

534 citations


Journal ArticleDOI
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.

524 citations


Journal ArticleDOI
TL;DR: In this article, the surface energy per surface atom is proportional to the cohesive energy per bulk atom, and a simple relationship between adsorbate-substrate vibrational stretch frequencies and their desorption energies follows from the universal relationship.
Abstract: Binding-energy-distance relations for metallic systems are shown to exhibit a universal behavior under a simple two-parameter scaling. All currently available ab initio calculations for the cohesion and adhesion of metals, as well as the chemisorption of gas atoms on metal surfaces, are shown to be determined by this single relation. Further, the energetics of diatomic molecules are determined by the same relation, despite the existence of strong volume-dependent forces for metals. These findings suggest a commonality of metallic bonding and a close relationship between molecular and metallic bonding. The universal nature of binding-energy-distance relations implies relations between seemingly disparate physical phenomena. As an example we show that the surface-binding-energy relation can be approximately expressed in terms of the bulk quantities. This leads to an explanation of the well-known empirical result that the surface energy per surface atom is proportional to the cohesive energy per bulk atom. Also, a simple relationship between adsorbate-substrate vibrational stretch frequencies and their desorption energies follows from the universal relationship.

483 citations


Journal ArticleDOI
TL;DR: In this article, the authors generalized the coupling of n=1 super-Maxwell theory and n = 1 supergravity in 10-dimensions to the case of a non-abelian gauge group.


Journal ArticleDOI
01 Oct 1983-Icarus
TL;DR: In this paper, the authors used the maximum Liapunov characteristic exponent and its importance for determining the character of a trajectory to trace out the chaotic zone near the 3/1 commensurability, both in the planar-ecliptic problem and in the three-dimensional elliptic problem.

Journal ArticleDOI
TL;DR: A deformed prism and a flanking forearc basin extending from Birjand southeast to Zahedan, Iran, record the destruction of an arm of the Neo-Tethys during Senonian-Paleocene time and consequent collision of the Afghan and Lut eratonic blocks as discussed by the authors.
Abstract: A deformed accretionary prism and a flanking forearc basin extending from Birjand southeast to Zahedan, Iran, record the destruction of an arm of the Neo-Tethys during Senonian-Paleocene time and consequent collision of the Afghan and Lut eratonic blocks. The accretionary prism at 32 °N is subdivided into two northwest-trending en echelon belts termed the “Ratuk” and “Neh” complexes, respectively. On the east, the Ratuk complex is characterized by ophiolitic block-against-block or serpentinite-matrix melange and large fault slivers of epidote blueschist tectonite. The Ratuk complex was built prior to Maastrichtian time. The Neh complex to the southwest is Senonian to Eocene in age and includes, in addition to ophiolitic melange, weakly metamorphosed marine sedimentary rock exposed in extensive belts bounded by steeply dipping faults. The Sefidabeh forearc basin deposits onlap both the Neh and Ratuk complexes and the southwest margin of the Afghan block. They make up as much as 8 km of Cenomanian to Eocene terrigenous elastics and carbonates that display a complex but coherent stratigraphy. Facies relations demonstrate the uplift and subaerial exposure of the Ratuk structural high, followed by its subsidence contemporaneous with construction of the Neh complex and calc-alkalic volcanism on the northeast (inner) side of the basin. The accretionary prism-forearc basin polarity, the structural vergence and general younging of the accretionary prism to the southwest, as well as the position of the (relatively) high P T metamorphic rock on the inner side of the prism are consistent with northeast-dipping subduction. Widespread emergence of the entire belt and the initiation of folding of the Sefidabeh basin deposits during middle Eocene are interpreted to be consequences of the entry of the Lut block into the subduction zone. Continued convergence of the continental blocks is expressed by a regional system of folds and transcurrent faults corresponding to east-northeast compression. These structures are buried by mildly deformed Miocene volcanic rocks. Extensive post-Miocene right-slip faulting is inferred to be an effect of Miocene “terminal” collision of Arabia and Eurasia.

Journal ArticleDOI
01 May 1983-Geology
TL;DR: Sediment gravity flows (subaerial or subaqueous) are those in which movement is driven by gravity and the sediment motion moves the interstitial fluid (gas or liquid) as mentioned in this paper.
Abstract: Sediment gravity flows (subaerial or subaqueous) are those in which movement is driven by gravity and the sediment motion moves the interstitial fluid (gas or liquid). Such flows exhibit flow transformations , a term introduced here, referring to changes between laminar and turbulent flow, in turn related chiefly to particle concentration, thickness of the flow, and flow velocity (slope).

Journal ArticleDOI
TL;DR: In this paper, a simple extension of the model developed by Alonso, Muth, and others is proposed to explain why the rich move to the suburbs and the poor return to the city center.

Journal ArticleDOI
TL;DR: In this paper, the velocity of the propagating front and the wavelength of the pattern formed behind the front are determined by a marginal-stability criterion, where the periodic state which propagates is not the one which minimizes the functional.
Abstract: Pattern selection is discussed in regard to a situation where a stable, nonuniform state of a nonlinear dissipative system propagates into an initially unstable, homogeneous region. The velocity of the propagating front and the wavelength of the pattern formed behind the front are determined by a marginal-stability criterion. The special system studied here has a Lyapunov functional, but the periodic state which propagates is not the one which minimizes the functional.

Journal ArticleDOI
TL;DR: In this paper, four morphotypes of structurally preserved, filamentous fossil bacteria have been discovered in petrographic thin sections of laminated, carbonaceous cherts from the ~3500 Ma-old Warrawoona Group of northwestern Australia.

Journal ArticleDOI
TL;DR: The mathematics of a push-pull model are shown to incorporate many of Ravenstein's laws of migration, to be equivalent to a quadratic transportation problem, and to be related to the mathematics of classical continuous-flow models as mentioned in this paper.
Abstract: The mathematics of a push-pull model are shown to incorporate many of Ravenstein's laws of migration, to be equivalent to a quadratic transportation problem, and to be related to the mathematics of classical continuous-flow models. These results yield an improved class of linear spatial interaction models. Empirical results are presented for one country.

Journal ArticleDOI
13 May 1983-Science
TL;DR: The functional organization of the second cortical visual area was examined with three different anatomical markers: 2-[14C]deoxy-D-glucose, cytochrome oxidase, and various myelin stains, which revealed strips running throughout the area, parallel to the cortical surface.
Abstract: The functional organization of the second cortical visual area was examined with three different anatomical markers: 2-[14C]deoxy-D-glucose, cytochrome oxidase, and various myelin stains. All three markers revealed strips running throughout the area, parallel to the cortical surface. The boundaries of these strips provide an anatomical criterion for defining the borders of this extrastriate region. Further, the demonstration of these strips allows a functional and anatomical analysis of modules in the area, just as the recent demonstration of spots in the primary visual cortex has allowed an analysis of modules there. The strips differ structurally and functionally from interstrip regions and these differences are similar to those seen between the spots and the interspot regions in the primary visual cortex. In the macaque the strips and spots differ with regard to binocular organization.

Journal ArticleDOI
01 Feb 1983-Nature
TL;DR: In this article, the formation of mineral zoning across the walls of these structures throughout two major growth phases, a sulphate-dominated stage and a sulphide replacement stage, is discussed.
Abstract: Hollow mineral spires known as ‘black smoker’ chimneys precipitate around 350 °C jets of hydrothermal fluid spouting from the sea floor on the East Pacific Rise (EPR) at 21° N (refs 1, 2). I describe and discuss here the formation of mineral zoning across the walls of these structures throughout two major growth phases, a sulphate-dominated stage and a sulphide replacement stage. During the sulphide replacement stage, at least four distinct sulphide mineral zonation sequences develop across chimney walls from interior to exterior. The apparently successive formation of these sulphide zonation sequences is attributed to evolution of radial thermal and chemical gradients accompanying the gradual thickening and sealing of black smoker chimney walls.

Journal ArticleDOI
TL;DR: In this article, a class of N = 2 supersymmetric models consisting of n = 2 Yang-Mills coupled to n 2 matter is shown to be finite to all orders of perturbation theory.

Journal ArticleDOI
TL;DR: A methodology for discovering storage and timing channels that can be used through all phases of the software life cycle to increase confidence that all channels have been identified is presented.
Abstract: Recognizing and dealing with storage and timing channels when performing the security analysis of a computer system is an elusive task. Methods for discovering and dealing with these channels have mostly been informal, and formal methods have been restricted to a particular specification language. A methodology for discovering storage and timing channels that can be used through all phases of the software life cycle to increase confidence that all channels have been identified is presented. The methodology is presented and applied to an example system having three different descriptions: English, formal specification, and high-order language implementation.

Journal ArticleDOI
TL;DR: In this paper, the authors compute the enhancement of light by a structure consisting of a sphere and a half-space, and study the dependence of the enhancement factor on the nature of the material, the geometric parameters, the light frequency and polarization, and on the spatial position.

Journal ArticleDOI
TL;DR: The second-order Jahn-Teller effect as mentioned in this paper is an example of reactions proceeding by an interaction between the HOMO and the LUMO within the same molecule.
Abstract: The second-order Jahn-Teller effect is an example of reactions proceeding by an interaction between the HOMO and the LUMO within the same molecule. The consequences can be decomposition of the molecule or a structural change. First the general theory is given, and then a number of examples are presented.

Journal ArticleDOI
TL;DR: In this article, an exact renormalization group transformation is developed for dissipative systems which describes how the transition to chaos may occur in a continuous and universal manner if the frequency ratio in the quasi-periodic regime is held at a fixed irrational value.

Journal ArticleDOI
28 Jan 1983-Science
TL;DR: Daily otolith increments were used to determine the daily pattern of settlement of the bluehead wrasse (Thalassoma bifasciatum), a Caribbean coral reef fish, and the population dynamics of this species may be determined by the supply of recruits and not by the Supply of space or some other resource on the reef.
Abstract: Daily otolith increments were used to determine the daily pattern of settlement of the bluehead wrasse (Thalassoma bifasciatum), a Caribbean coral reef fish. Recruitment occurs in brief and sporadic episodes even though bluehead wrasses spawn every day. Patterns of recruitment do not correspond to patterns of mortality on the reef. The composition of the adult population directly reflects the relative rates of recruitment of juveniles the year before. The population dynamics of this species may therefore be determined by the supply of recruits and not by the supply of space or some other resource on the reef.

Journal ArticleDOI
TL;DR: In this article, the formulation of gauge theories on Euclidean space-time lattices and the application of the Monte Carlo computational technique to the ensuing systems are reviewed and a variety of numerical results obtained for lattice gauge theories are presented and discussed.


Journal ArticleDOI
TL;DR: The authors found that men interpreted the vignettes more positively than did women, especially women, when the touching was combined with a comment on work, and this effect was exacerbated when the behavior was initiated by a male and/or higher status person.