Showing papers in "Annalen der Physik in 2000"
TL;DR: In this article, a simple model of conditional quantum dynamics is introduced and investigated, which allows for a discussion of the information-theoretic aspects of quantum measurements, decoherence, and environment-induced superselection.
Abstract: We introduce and investigate a simple model of conditional quantum dynamics. It allows for a discussion of the information-theoretic aspects of quantum measurements, decoherence, and environment-induced superselection (einselection).
247 citations
TL;DR: In this article, the authors study extended theories of gravity where nonminimal derivative couplings of the form Rφ, kφ and l are present in the Lagrangian and derive the field equations and related cosmological models.
Abstract: We study extended theories of gravity where nonminimal derivative couplings of the form Rφ, kφ, l are present in the Lagrangian. We show how and why the other couplings of similar structure may be ruled out and then deduce the field equations and the related cosmological models. Finally, we get inflationary solutions which do follow neither from any effective scalar field potential nor from a cosmological constant introduced “by hand”, and we show the de Sitter space–time to be an attractor solution. PACS number(s): 04.50.+h, 98.80.Cq Keyword(s): Cosmology, Alternative Theories of Gravity, Nonminimal Coupling. E-mail: capozziello@vaxsa.csied.unisa.it E-mail: lambiase@physics.unisa.it E-mail: hjschmi@rz.uni-potsdam.de
174 citations
TL;DR: In this paper, the physics underlying the operation of SETs is explained, a brief history of its invention is presented, and issues of current interest are discussed, as well as a review of the SET and its application in various applications.
Abstract: Modern techniques of lithography make it possible to confine electrons to sufficiently small dimensions that the quantization of both their charge and their energy are easily observable. When such confined electrons are allowed to tunnel to metallic leads a single electron transistor (SET) is created. This transistor turns on and off again every time one electron is added to the isolated region. Whereas we can understand conventional transistors using classical concepts, the SET is quantum mechanical in an essential way. In fact, there is a close analogy between the confined electrons inside an SET and an atom. In this review, the physics underlying the operation of SETs is explained, a brief history of its invention is presented, and issues of current interest are discussed.
108 citations
TL;DR: In this paper, the static elastoplastic theory of dislocations in an elastic material was considered and a Yang-Mills type Lagrangian and some Lagrangians with anisotropic constitutive laws were used to express the balance of force and moment.
Abstract: We consider the static elastoplastic theory of dislocations in an elastoplastic material We use a Yang-Mills type Lagrangian (the teleparallel equivalent of Hilbert-Einstein Lagrangian) and some Lagrangians with anisotropic constitutive laws The translational part of the generalized affine connection is utilized to describe the theory of elastoplasticity in the framework of a translation gauge theory We obtain a system of Yang-Mills field equations which express the balance of force and moment
60 citations
54 citations
TL;DR: In this article, a pedagogical introduction to quantum phase transitions and quantum critical behavior emphasizing similarities with and differences to classical thermal phase transitions is given, and a few examples of quantum phase transition occurring in electronic systems are discussed.
Abstract: Quantum phase transitions occur at zero temperature when some non-thermal control-parameter like pressure or chemical composition is changed. They are driven by quantum rather than thermal fluctuations. In this review we first give a pedagogical introduction to quantum phase transitions and quantum critical behavior emphasizing similarities with and differences to classical thermal phase transitions. We then illustrate the general concepts by discussing a few examples of quantum phase transitions occurring in electronic systems. The ferromagnetic transition of itinerant electrons shows a very rich behavior since the magnetization couples to additional electronic soft modes which generates an effective long-range interaction between the spin fluctuations. We then consider the influence of rare regions on quantum phase transitions in systems with quenched disorder, taking the antiferromagnetic transitions of itinerant electrons as a primary example. Finally we discuss some aspects of the metal-insulator transition in the presence of quenched disorder and interactions.
53 citations
45 citations
TL;DR: In this article, the wave front set of the free Klein-Gordon field in a Hadamard state is reviewed, and the polarization set of a hadamard two point function of free Dirac field on a curved spacetime is calculated.
Abstract: We give an introduction to the techniques from microlocal analysis that have successfully been applied in the investigation of Hadamard states of free quantum field theories on curved spacetimes. The calculation of the wave front set of the two point function of the free Klein-Gordon field in a Hadamard state is reviewed, and the polarization set of a Hadamard two point function of the free Dirac field on a curved spacetime is calculated.
37 citations
TL;DR: In this paper, the strong friction limit of the Caldeira-Leggett model for quantum Brownian motion is analyzed and the density operator of the Brownian particle is essentially diagonal in coordinate, and the diagonal element satisfies the classical Smoluchowski equation.
Abstract: The strong friction limit of the Caldeira-Leggett model for quantum Brownian motion is analyzed. In this Smoluchowski limit the density operator of the Brownian particle is essentially diagonal in coordinate, and the diagonal element satisfies the classical Smoluchowski equation. This result cannot be obtained from the master equations that have been proposed for quantum Brownian motion, whether or not these equations are of Lindblad form.
32 citations
TL;DR: In this article, a general analytic expression has been obtained and confirmed by a computer simulation which links the surface roughness of an object under study in an emission electron microscope and it's resolution.
Abstract: In the present paper a general analytic expression has been obtained and confirmed by a computer simulation which links the surface roughness of an object under study in an emission electron microscope and it's resolution A quantitative derivation was made for the model case when there is a step on the object surface It was shown that the resolution is deteriorated asymmetrically relative to the step The effect sets a practical limit to the ultimate lateral resolution obtainable in an emission electron microscope
30 citations
TL;DR: In this paper, past, present and future experimental tests of quantum nonlocality are discussed and the consequences of assuming that the state-vector collapse is a real physical phenomenon in space-time are developed.
Abstract: Past, present and future experimental tests of quantum nonlocality are discussed. Consequences of assuming that the state-vector collapse is a real physical phenomenon in space-time are developed. These lead to experiments feasible with today's technology.
TL;DR: In this article, the authors studied directed transport in classical and quantum area-preserving maps, periodic in space and momentum, and showed that a sum rule excludes directed transport of the entire phase space, leaving only the possibility of transport in (dynamically defined) subsets, such as regular islands or chaotic areas.
Abstract: We study directed transport in classical and quantum area-preserving maps, periodic in space and momentum. On the classical level, we show that a sum rule excludes directed transport of the entire phase space, leaving only the possibility of transport in (dynamically defined) subsets, such as regular islands or chaotic areas. As a working example, we construct a mapping with a mixed phase space where both the regular and the chaotic components support directed currents, but with opposite sign. The corresponding quantum system shows transport of similar strength, associated to the same subsets of phase space as in the classical map.
TL;DR: In this paper, the falloff behavior of the fields at null infinity, put in after a judicious choice "by hand", is specified in terms of suitable parameters along the generators of the null hypersurfaces.
Abstract: Following (12), we discuss how asymptotic quantities, originally introduced on null infinity in terms of Bondi-type gauge conditions, can be calculated near space-like infinity to any desired precision. Null infinity is the most interesting asymptotic domain of asymptotically flat space- times, since it is here where information on dynamical processes which take place in the interior of space-times is registered by the ideal observer at infinity. The early investigations of asymptotical flatness in null directions ((5), (15), (20)) are based on the notion of "Bondi-type" coordinates and associated gauge conditions, which involve as a basic ingredient families of outgoing null hypersurfaces of the form {u = const.} with a smooth function u. Such coordinates play a distinguished role in these studies, because the fall-off behavior of the fields at null infinity, put in after a judicious choice "by hand", is specified in terms of suitable parameters along the generators of the null hypersurfaces. In the following we shall mainly be concerned with the idea of asymptotic sim- plicity ((18), (19)). This proposal to characterize the fall-off behavior of gravitational fields in terms of the light cone structure does not require the use of preferred classes of coordinates. Nevertheless, because null hypersurfaces are conformally invariant structures and are closely related to certain features of gravitational field propagation, Bondi-type gauge conditions have been used so extensively also in this context that they may appear to be naturally associated with the analysis of asymptotic properties of gravitational fields. We shall see in the following that there are good reasons to consider also other coordinates and gauge conditions in the study of asymptotics.
TL;DR: In this paper, a review of the ultraviolet difficulties faced by local quantum gravity theories in both the usual Einstein versions and in their supergravity extensions, at least perturbatively, is presented.
Abstract: We first present a review, intended for classical relativists, of the ultraviolet difficulties faced by local quantum gravity theories in both the usual Einstein versions and in their supergravity extensions, at least perturbatively. These problems, present in arbitrary dimensions, are traceable to the dimensionality of the Einstein constant.We then summarize very recent results about supergravity at the highest allowed dimension, D = 11, showing that also this unique model suffers from infinities already at 2 loops, despite its high degree of supersymmetry. The conclusion is that there is no viable nonghost quantum field model that includes general relativity.
TL;DR: The discovery of the Compton effect at the end of 1922 was a decisive event in the transition to the new quantum mechanics of 1925-1926 because it stimulated physicists to examine anew the fundamental problem of the interaction between radiation and matter as discussed by the authors.
Abstract: The discovery of the Compton effect at the end of 1922 was a decisive event in the transition to the new quantum mechanics of 1925-1926 because it stimulated physicists to examine anew the fundamental problem of the interaction between radiation and matter. I first discuss Albert Einstein's light-quantum hypothesis of 1905 and why physicists greeted it with extreme skepticism, despite Robert A. Millikan's confirmation of Einstein's equation of the photoelectric effect in 1915. I then follow in some detail the experimental and theoretical research program that Arthur Holly Compton pursued between 1916 and 1922 at the University of Minnesota, the Westinghouse Lamp Company, the Cavendish Laboratory, and Washington University that culminated in his discovery of the Compton effect. Surprisingly, Compton was not influenced directly by Einstein's light-quantum hypothesis, in contrast to Peter Debye and H.A. Kramers, who discovered the quantum theory of scattering independently. I close by discussing the most significant response to that discovery, the Bohr-Kramers-Slater theory of 1924, its experimental refutation, and its influence on the emerging new quantum mechanics.
TL;DR: In this article, the origins, peculiarities, and evolution of Planck's approach to derive the correct black-body law are explained and the status of the energy-elements which Planck thereby introduced is examined.
Abstract: Planck's famous communication of December 1900 cannot be understood without taking into account an essential difference between his and Boltzmann's conceptions of the relation between micro- and macro-world For Boltzmann, macroscopic laws were in principle completely determined by the underlying microscopic dynamics For Planck, the microscopic dynamics were partly undetermined and had to be supplemented by additional assumptions in order to reach macroscopic lawsThanks to this leeway, Planck could introduce finite energy-elements and derive his famous black-body law without giving up the continuity and determinism of former dynamical theories The purpose of this paper is to explain the origins, peculiarities, and evolution of Planck's approach; to show how it ultimately yielded the correct black-body law; and to examine the status of the energy-elements which Planck thereby introduced
TL;DR: In this paper, the authors consider globally coupled particles, each of them governed by a deterministic relaxation dynamics in a critically tilted washboard potential, but without a preferential spatial direction for the coupled system as a whole.
Abstract: We consider globally coupled particles, each of them governed by a deterministic relaxation dynamics in a critically tilted washboard potential, but without a preferential spatial direction for the coupled system as a whole. For weak-to-moderate coupling we observe a spontaneous breaking of the system intrinsic symmetry which entails a spontaneous collective transport via a ratchet effect, possibly with a superimposed oscillatory long time behavior. For strong coupling, spontaneous symmetry breaking and spontaneous directed current are ruled out, whereas a negative mobility in response to an externally applied force is recovered.
TL;DR: In this paper, exact solutions of Einstein's equations in 2+1-dimensional anti-de Sitter space containing any number of black holes are described and the time development and horizon structure of some of these spacetimes are sketched.
Abstract: Exact solutions of Einstein’s equations in 2+1-dimensional anti-de Sitter space containing any number of black holes are described. In addition to the black holes these spacetimes can possess “internal” structure. Accordingly the generic spacetime of this type depends on a large number of parameters. Half of these can be taken as mass parameters, and the rest as the conjugate (angular) momenta. The time development and horizon structure of some of these spacetimes are sketched.
TL;DR: In this article, the orbital dynamics of the binary point-mass systems is ambiguous at the third post-Newtonian order of approximation, which violates the standard relation between the center-of-mass velocity and the total linear momentum as demanded by global Lorentz invariance.
Abstract: The orbital dynamics of the binary point-mass systems is ambiguous at the third post-Newtonian order of approximation. The static ambiguity is known to be related to the difference between the Brill-Lindquist solution and the Misner-Lindquist solution of the time-symmetric conformally flat initial value problem for binary black holes.The kinetic ambiguity is noticed to violate in general the standard relation between the center-of-mass velocity and the total linear momentum as demanded by global Lorentz invariance.
TL;DR: In this paper, the authors studied the statistics of pronounced arcs caused by lensing of galaxies by foreground galaxy clusters, and the dependence of the expected statistics on the cosmological parameters, M, �, was investigated.
Abstract: We study with semi-analytical methods the statistics of pronounced arcs caused by lensing of galaxies by foreground galaxy clusters. For the number density and redshift distribution of rich clusters we use Press-Schechter theory, normalized on the basis of empirical data. For the background sources we make use of observational results in the Hubble Deep Field. We present results for three different lens models, in particular for the universal profile suggested by Navarro, Frenk and White. Our primary concern is the dependence of the expected statistics on the cosmological parameters, M, �. The theoretical estimates are compared with the cluster arcs survey EMSS, and the resulting constraints in the -plane are presented. In spite of considerable theoretical an observational uncertainties a low-density universe is favored. Degeneracy curves for the optical depth and likelihood regions for the arc statistics in the -plane depend only weakly on the cosmological constant.
TL;DR: In this article, the gravitomagnetic clock effect for rotating cylindrical systems is investigated for the exterior vacuum field of an infinite rotating cylinder and the dependence of the clock effect on the Weyl parameters of the stationary Lewis metric is determined.
Abstract: We discuss gravitomagnetism in connection with rotating cylindrical systems. In particular, the gravitomagnetic clock effect is investigated for the exterior vacuum field of an infinite rotating cylinder. The dependence of the clock effect on the Weyl parameters of the stationary Lewis metric is determined. We illustrate our results by means of the van Stockum spacetime.
TL;DR: In this paper, three topics of current interest are briefly reviewed: binary black hole mergers, the evolution of strong gravitational waves, and shift conditions for neutron star binaries, and a general introduction is given.
Abstract: Numerical relativity is finally approaching a state where the evolution of rather general (3+1)-dimensional data sets can be computed in order to solve the Einstein equations. After a general introduction, three topics of current interest are briefly reviewed: binary black hole mergers, the evolution of strong gravitational waves, and shift conditions for neutron star binaries.
TL;DR: In this article, the sequence of phase transitions during the hot history of the universe is followed within a phenomenological framework, with particular emphasis on the QCD confinement transition, which is at reach under earth laboratory conditions.
Abstract: The sequence of phase transitions during the hot history of the universe is followed within a phenomenological framework. Particular emphasis is put on the QCD confinement transition, which is at reach under earth laboratory conditions. A tepid inflationary scenario on the GUT scale with bubble growth at moderate supercooling is discussed.
TL;DR: In this article, the inelastic neutron scattering spectra of heavy fermion semiconductors were examined in the context of the indirect hybridization gap model and the in-gap features were identified as excitations of magnetic bound states, which are induced by residual anti-ferromagnetic interactions between the renormalized quasi-particles.
Abstract: The heavy fermion semiconductors such as Ce3Bi4Pt3, YbB12, and SmB6 may be modeled as indirect hybridization gap semiconductors. The magnitudes of the gap are smaller than the gaps predicted by local density functional electronic structure calculations, suggesting strong renormalizations due to electronic correlations. The inelastic neutron scattering spectra Im[χ(q,ω)] are examined within the context of this model. Anomalously sharp and temperature dependent peaks are seen at energies within the indirect gap in the inelastic neutron scattering experiments on SmB6 and YbB12 The in-gap features are identified as excitations of magnetic bound states, which are induced by residual anti-ferromagnetic interactions between the renormalized quasi-particles.
TL;DR: In this paper, the authors apply the antifield quantization method of Batalin and Vilkovisky to the calculation of the path integral for the Poisson-Sigma model in a general gauge.
Abstract: We apply the antifield quantization method of Batalin and Vilkovisky to the calculation of the path integral for the Poisson-Sigma model in a general gauge. For a linear Poisson structure the model reduces to a nonabelian gauge theory, and we obtain the formula for the partition function of two-dimensional Yang-Mills theory for closed oriented two-dimensional manifolds.
TL;DR: In this article, isolated horizons can be located in a space-time quasi-locally, and the zeroth and first laws of black hole mechanics extend to isolated horizon.
Abstract: The arena normally used in black holes thermodynamics was recently generalized to incorporate a broad class of physically interesting situations. The key idea is to replace the notion of stationary event horizons by that of `isolated horizons.' Unlike event horizons, isolated horizons can be located in a space-time quasi-locally. Furthermore, they need not be Killing horizons. In particular, a space-time representing a black hole which is itself in equilibrium, but whose exterior contains radiation, admits an isolated horizon. In spite of this generality, the zeroth and first laws of black hole mechanics extend to isolated horizons. Furthermore, by carrying out a systematic, non-perturbative quantization, one can explore the quantum geometry of isolated horizons and account for their entropy from statistical mechanical considerations. After a general introduction to black hole thermodynamics as a whole, these recent developments are briefly summarized.
TL;DR: In this article, the authors proposed a quantum canonical partition function for 1st-order phase transitions in D-2 spatial dimensions, which is based on the Ising droplet nucleation model.
Abstract: Generalizing previous quantum gravity results for Schwarzschild black holes from 4 to D > 3 space-time dimensions yields an energy spectrum E_n = alpha n^{(D-3)/(D-2)} E_P, n=1,2,..., alpha = O(1), where E_P is the Planck energy in that space-time. This spectrum means that the quantized area A_{D-2}(n) of the D-2 dimensional horizon has universally the form A_{D-2} = n a_{D-2}, where a_{D-2} is essentially the (D-2)th power of the D-dimensional Planck length. Assuming that the basic area quantum has a Z(2)-degeneracy according to its two possible orientation degrees of freedom implies a degeneracy d_n = 2^n for the n-th level. The energy spectrum with such a degeneracy leads to a quantum canonical partition function which is the same as the classical grand canonical partition function of a primitive Ising droplet nucleation model for 1st-order phase transitions in D-2 spatial dimensions. The analogy to this model suggests that E_n represents the surface energy of a "droplet" of n horizon quanta. Exploiting the well-known properties of the so-called critical droplets of that model immediately leads to the Hawking temperature and the Bekenstein-Hawking entropy of Schwarzschild black holes. The values of temperature and entropy appear closely related to the imaginary part of the partition function which describes metastable states
TL;DR: In this article, the properties of low-dimensional quantum antiferromagnets in applied magnetic fields were analyzed using a spin stiffness analysis, a 1/N expansion, and a renormalization group approach.
Abstract: We present a theoretical analysis of the properties of low-dimensional quantum antiferromagnets in applied magnetic fields. In a nonlinear a model description, we use a spin stiffness analysis, a 1/N expansion, and a renormalization group approach to describe the broken-symmetry regimes of finite magnetization, and, in cases of most interest, a low-field regime where symmetry is restored by quantum fluctuations. We compute the magnetization, critical fields, spin correlation functions, and decay exponents accessible by nuclear magnetic resonance experiments. The model is relevant to many systems exhibiting Haldane physics, and provides good agreement with data for the two-chain spin ladder compound CuHpCl.