Showing papers on "Anomaly (physics) published in 2001"
CERN1
TL;DR: In this paper, the authors studied RR charge cancellation consistency conditions in string compactifications with open string sectors, by introducing D-brane probes in the configuration, and showed that uncancelled charges manifest as chiral gauge anomalies in the world-volume of suitable probes.
232 citations
TL;DR: In this paper, the authors investigated Starobinsky's model of inflation driven by the trace anomaly of conformally coupled matter fields and derived the correlation function for scalar and tensor metric perturbations during the ensuing de Sitter phase.
Abstract: This paper investigates Starobinsky's model of inflation driven by the trace anomaly of conformally coupled matter fields. This model does not suffer from the problem of contrived initial conditions that occurs in most models of inflation driven by a scalar field. The universe can be nucleated semiclassically by a cosmological instanton that is much larger than the Planck scale provided there are sufficiently many matter fields. There are two cosmological instantons: the four sphere and a new ``double bubble'' solution. This paper considers a universe nucleated by the four sphere. The AdS/CFT correspondence is used to calculate the correlation function for scalar and tensor metric perturbations during the ensuing de Sitter phase. The analytic structure of the scalar and tensor propagators is discussed in detail. Observational constraints on the model are discussed. Quantum loops of matter fields are shown to strongly suppress short scale metric perturbations, which implies that short distance modifications of gravity would probably not be observable in the cosmic microwave background. This is probably true for any model of inflation provided there are sufficiently many matter fields. This point is illustrated by a comparison of anomaly driven inflation in four dimensions and in a Randall-Sundrum brane-world model.
188 citations
TL;DR: It is proved that global anomaly cancellation requires more than one generation of quarks and leptons, provided that the standard model fields propagate in two universal extra dimensions.
Abstract: We prove that global anomaly cancellation requires more than one generation of quarks and leptons, provided that the standard model fields propagate in two universal extra dimensions. Furthermore, if the fermions of different generations have the same gauge charges and chiralities, then global anomaly cancellation implies that there must be three generations.
167 citations
TL;DR: The merger of density-functional theory in the local density approximation and many-body dynamical mean-field theory allows for an ab initio calculation of Ce including the inherent 4f electronic correlations and shows that the physical origin of the energy anomaly and the volume collapse is the appearance of a quasiparticle resonance in the 4f-spectrum which is accompanied by a rapid growth in the double occupancy.
Abstract: The merger of density-functional theory in the local density approximation and many-body dynamical mean-field theory allows for an ab initio calculation of Ce including the inherent 4f electronic correlations. We solve the equations by the quantum Monte Carlo technique and calculate the Ce energy, spectrum, and double occupancy as a function of volume. At low temperatures, the correlation energy exhibits an anomalous region of negative curvature which drives the system towards a thermodynamic instability, i.e., the gamma-to- alpha volume collapse, consistent with experiment. The connection of the energetic with the spectral evolution shows that the physical origin of the energy anomaly and, thus, the volume collapse is the appearance of a quasiparticle resonance in the 4f-spectrum which is accompanied by a rapid growth in the double occupancy.
145 citations
TL;DR: In this article, the authors studied the one-loop dynamics of QFT on the fuzzy sphere and calculated the planar and nonplanar contributions to the two point function at one loop.
Abstract: We study the one loop dynamics of QFT on the fuzzy sphere and calculate the planar and nonplanar contributions to the two point function at one loop. We show that there is no UV/IR mixing on the fuzzy sphere. The fuzzy sphere is characterized by two moduli: a dimensionless parameter N and a dimensionful radius R. Different geometrical phases can obtained at different corners of the moduli space. In the limit of the commutative sphere, we find that the two point function is regular without UV/IR mixing; however quantization does not commute with the commutative limit, and a finite ``noncommutative anomaly'' survives in the commutative limit. In a different limit, the noncommutative plane 2θ is obtained, and the UV/IR mixing reappears. This provides an explanation of the UV/IR mixing as an infinite variant of the ``noncommutative anomaly''.
143 citations
TL;DR: In this article, the form of the chiral anomaly on an S1/Z2 orbifold with chiral boundary conditions was discussed and it was shown that the 4-divergence of the higher-dimensional current evaluated at a given point in the extra dimension is proportional to the probability of finding the Chiral zero mode there.
135 citations
11 Jun 2001
TL;DR: A statistical anomaly detection algorithm based on Markov chains that can be directly applied for intrusion detection by discovering anomalous activities and performance metrics for evaluating the effectiveness of anomaly detectors are presented.
Abstract: This paper presents a statistical anomaly detection algorithm based on Markov chains. Our algorithm can be directly applied for intrusion detection by discovering anomalous activities. Our framework for constructing anomaly detectors is very general and can be used by other researchers for constructing Markov-chain-based anomaly detectors. We also present performance metrics for evaluating the effectiveness of anomaly detectors. Extensive experimental results clearly demonstrate the effectiveness of our algorithm. We discuss several future directions for research based on the framework presented in this paper.
127 citations
TL;DR: The interaction of an electron with a polar molecule is shown to be the simplest realization of a quantum anomaly in a physical system and the existence of a critical dipole moment for electron capture and formation of anions is derived.
Abstract: The interaction of an electron with a polar molecule is shown to be the simplest realization of a quantum anomaly in a physical system. The existence of a critical dipole moment for electron capture and formation of anions, which has been confirmed experimentally and numerically, is derived. This phenomenon is a manifestation of the anomaly associated with quantum symmetry breaking of the classical scale invariance exhibited by the point-dipole interaction. Finally, analysis of symmetry breaking for this system is implemented within two different models: point dipole subject to an anomaly and finite dipole subject to explicit symmetry breaking.
117 citations
TL;DR: In this paper, the nonlinear supersymmetry of one-dimensional systems is investigated in the context of the quantum anomaly problem, and the most general one-parametric Calogero-like solution with the second order supercharges is found.
113 citations
TL;DR: In this paper, the authors studied the one-loop dynamics of QFT on the fuzzy sphere and calculated the planar and nonplanar contributions to the two point function at one loop.
Abstract: We study the one loop dynamics of QFT on the fuzzy sphere and calculate the planar and nonplanar contributions to the two point function at one loop. We show that there is no UV/IR mixing on the fuzzy sphere. The fuzzy sphere is characterized by two moduli: a dimensionless parameter N and a dimensionful radius R. Different geometrical phases can obtained at different corners of the moduli space. In the limit of the commutative sphere, we find that the two point function is regular without UV/IR mixing; however quantization does not commute with the commutative limit, and a finite ``noncommutative anomaly'' survives in the commutative limit. In a different limit, the noncommutative plane R^2_theta is obtained, and the UV/IR mixing reappears. This provides an explanation of the UV/IR mixing as an infinite variant of the ``noncommutative anomaly''.
112 citations
TL;DR: In this article, it was shown that for certain spin topologies, including recently synthesised icosidodecahedral structures, the minimal energies are a linear function of total spin.
Abstract: For many spin systems with constant isotropic antiferromagnetic next-neighbour Heisenberg coupling the minimal energies E
min(S) form a rotational band, i.e. depend approximately quadratically on the total spin quantum number S, a property which is also known as Lande interval rule. However, we find that for certain coupling topologies, including recently synthesised icosidodecahedral structures this rule is violated for high total spins. Instead the minimal energies are a linear function of total spin. This anomaly results in a corresponding jump of the magnetisation curve which otherwise would be a regular staircase.
01 Dec 2001
TL;DR: It is verified that Anomaly Dictionaries for the UNM's sendmail Program have very little overlap, and can be effectively used for Anomaly Classification, and it is shown that a hybrid scheme, combining the proposed classification strategy with the original Anomaly Counts can lead to a substantial improvement in the overall detection rates for the sendmail dataset.
Abstract: This paper investigates the use of sequences of system calls for classifying intrusions and faults induced by privileged processes in Unix. Classification is an essential capability for responding to an anomaly (attack or fault), since it gives the ability to associate appropriate responses to each anomaly type. Previous work using the well known dataset from the University of New Mexico (UNM) has demonstrated the usefulness of monitoring sequences of system calls for detecting anomalies induced by processes corresponding to several Unix Programs, such as sendmail, lpr, ftp, etc. Specifically, previous work has shown that the Anomaly Count of a running process, i.e., the number of sequences spawned by the process which are not found in the corresponding dictionary of normal activity for the Program, is a valuable feature for anomaly detection. To achieve Classification, in this paper we introduce the concept of Anomaly Dictionaries, which are the sets of anomalous sequences for each type of anomaly. It is verified that Anomaly Dictionaries for the UNM's sendmail Program have very little overlap, and can be effectively used for Anomaly Classification. The sequences in the Anomalous Dictionary enable a description of Self for the Anomalies, analogous to the definition of Self for Privileged Programs given by the Normal Dictionaries. The dependence of Classification Accuracy with sequence length is also discussed. As a side result, it is also shown that a hybrid scheme, combining the proposed classification strategy with the original Anomaly Counts can lead to a substantial improvement in the overall detection rates for the sendmail dataset. The methodology proposed is rather general, and can be applied to any situation where sequences of symbols provide an effective characterization of a phenomenon.
TL;DR: In this paper, the authors studied the performance of the transport of a quantum dot when an additional quantum dot lying in the Kondo regime is side-connected to it and showed that the conductance is suppressed at low temperatures and at low source-drain bias voltages.
Abstract: We report our study of $I\ensuremath{-}V$ curves in the transport through the quantum dot when an additional quantum dot lying in the Kondo regime is side-connected to it. Due to the Kondo scattering of the effective spin on a side-connected quantum dot, the conductance is suppressed at low temperatures and at low source-drain bias voltages. This zero-bias anomaly is understood as enhanced Kondo scattering with decreasing temperature.
TL;DR: In this paper, the authors derived the anomaly polynomial for D-type theories realized on N pairs of coincident M5-branes at R^5/Z_2 orbifold fixed point.
Abstract: We compute gravitational and axial anomaly for D-type (2,0) theories realized on N pairs of coincident M5-branes at R^5/Z_2 orbifold fixed point. We first summarize work by Harvey, Minasian, and Moore on A-type (2,0) theories, and then extend it to include the effect of orbifold fixed point. The net anomaly inflow follows when we further take into account the consistency of T^5/Z_2 M-theory orbifold. We deduce that the world-volume anomaly is given by N{\cal J}_8 + N(2N-1)(2N-2) p_2/24 where {\cal J}_8 is the anomaly polynomial of a free tensor multiplet and p_2 is the second Pontryagin class associated with the normal bundle. This result is in accord with Intriligator's conjecture.
TL;DR: In this article, the authors describe the complete coupling of (1, 0) six-dimensional supergravity to tensor, vector and hypermultiplets, and apply the Pasti-Sorokin-Tonin prescription to this model.
TL;DR: In this paper, the mass of tachyon fluctuation mode and the energy density associated with a classical solution of vacuum string field theory constructed previously were shown to vanish identically due to twist even-odd degeneracy of eigenvalues of a Neumann coefficient matrix defining the three-string interactions.
Abstract: We reveal a novel mathematical structure in physical observables, the mass of tachyon fluctuation mode and the energy density, associated with a classical solution of vacuum string field theory constructed previously [hep-th/0108150]. We find that they are expressed in terms of quantities which apparently vanish identically due to twist even-odd degeneracy of eigenvalues of a Neumann coefficient matrix defining the three-string interactions. However, they can give non-vanishing values because of the breakdown of the degeneracy at the edge of the eigenvalue distribution. We also present a general prescription of correctly simplifying the expressions of these observables. Numerical calculation of the energy density following our prescription indicates that the present classical solution represents the configuration of two D25-branes.
TL;DR: The tunneling density of states of doped multiwall nanotubes including disorder and electron-electron interactions is computed, finding a nonconventional Coulomb blockade reflecting nonperturbative Altshuler-Aronov-Lee power-law zero-bias anomalies is found.
Abstract: We compute the tunneling density of states of doped multiwall nanotubes including disorder and electron-electron interactions. A nonconventional Coulomb blockade reflecting nonperturbative Altshuler-Aronov-Lee power-law zero-bias anomalies is found, in accordance with recent experimental results. The presence of a boundary implies a universal doubling of the boundary exponent in the diffusive limit.
TL;DR: The axial anomaly of the noncommutative U(1) gauge theory is calculated by a number of methods and compared with the commutative one as mentioned in this paper, and it is found to be given by the corresponding Chern class.
Abstract: The axial anomaly of the noncommutative U(1) gauge theory is calculated by a number of methods and compared with the commutative one. It is found to be given by the corresponding Chern class.
TL;DR: In this article, the authors show that the dependence of the island density on the growth rate is modified by interactions, which could be used to identify adsorbate interactions in growth experiments.
Abstract: Highly anomalous values for the preexponential factor in atomic diffusion rates at surfaces have recently been inferred from scanning-tunneling microscopy growth experiments. In an extensive first-principles kinetic Monte Carlo study, we show how long-range adsorbate interactions invalidate the standard nucleation-theory approach to analyzing experimental island-density data. When adatom-adatom interactions are properly accounted for in the analysis of experimental data, the anomaly is lifted, and deduced prefactors are consistent with direct theoretical calculations. We show that the dependence of the island density on the growth rate is modified by interactions, which could be used to identify adsorbate interactions in growth experiments.
Posted Content•
TL;DR: In this paper, the authors describe the mechanism of anomaly cancellation in smooth manifolds of G_2 holonomy, which depends upon anomaly inflow from the bulk, and compare the anomaly predictions to what has been learned by more explicit arguments in some special cases.
Abstract: Smooth manifolds of G_2 holonomy, used to compactify M-theory to four dimensions, give only abelian gauge groups without charged matter multiplets. But singular G_2-manifolds can give abelian or nonabelian gauge groups with chiral fermions. We describe the mechanism of anomaly cancellation in these models, which depends upon anomaly inflow from the bulk. We also compare the anomaly predictions to what has been learned by more explicit arguments in some special cases.
TL;DR: In this article, the authors describe the complete coupling of $(1,0)$ six-dimensional supergravity to tensor, vector and hypermultiplets, and apply the Pasti-Sorokin-Tonin prescription to this model.
Abstract: We describe the complete coupling of $(1,0)$ six-dimensional supergravity to tensor, vector and hypermultiplets. The generalized Green-Schwarz mechanism implies that the resulting theory embodies factorized gauge and supersymmetry anomalies, to be disposed of by fermion loops. Consequently, the low-energy theory is determined by the Wess-Zumino consistency conditions, rather than by the requirement of supersymmetry. As already shown for the case without hypermultiplets, this procedure does not fix a quartic coupling for the gauginos. With respect to these previous results, the inclusion of charged hypermultiplets gives additional terms in the supersymmetry anomaly. We also consider the case in which abelian vectors are present. As in the absence of hypermultiplets, abelian vectors allow additional couplings. Finally, we apply the Pasti-Sorokin-Tonin prescription to this model.
TL;DR: In this article, the authors consider the possibility that some supersymmetric gauge theories which are not asymptotically free can be governed by ultraviolet-stable fixed points and show that these fixed points exhibit power-law running with scale.
Abstract: We consider the possibility that some supersymmetric gauge theories which are not asymptotically free can be governed by ultraviolet-stable fixed points. If this scenario can be realized, gaugino masses will exhibit power-law running with scale, providing a possible solution to the supersymmetric flavor problem. While naive perturbative calculations hint at the appearance of ultraviolet-stable fixed points in certain theories, there are strong constraints following from limits on the scaling dimensions of gauge-invariant operators, positivity of central charges, and Cardy's conjectured constraint on the flow of the Euler coefficient in the stress tensor trace anomaly. Also, we prove that if ultraviolet-stable fixed points do exist, they cannot occur in the perturbative regime of a renormalizable model, and that all-orders results in the limit of large numbers of chiral superfields are necessarily inconclusive. However, we argue that the general idea of ultraviolet-stable fixed points in supersymmetric gauge theories is viable, and exhibit models that can satisfy all known constraints.
TL;DR: In this article, a quantum-field theoretical interpretation is given to the holographic RG equation by relating it to a field-theoretical local RG equation which determines how Weyl invariance is broken in a quantized field theory.
Abstract: A quantum-field theoretical interpretation is given to the holographic RG equation by relating it to a field-theoretical local RG equation which determines how Weyl invariance is broken in a quantized field theory. Using this approach we determine the relation between the holographic C theorem and the C theorem in two-dimensional quantum field theory which relies on the Zamolodchikov metric. Similarly we discuss how in four dimensions the holographic C function is related to a conjectured field-theoretical C function. The scheme dependence of the holographic RG due to the possible presence of finite local counterterms is discussed in detail, as well as its implications for the holographic C function. We also discuss issues special to the situation when mass deformations are present. Furthermore we suggest that the holographic RG equation may also be obtained from a bulk diffeomorphism which reduces to a Weyl transformation on the boundary.
TL;DR: In this article, the authors examined the equilibrium properties of hot, non-relativistic plasmas and obtained explicit results for density-density correlation functions through two-loop order and thermodynamic quantities through threeloop order.
TL;DR: In this article, the Chern-Simons formulation of (2+1) -gravity is used to derive the emergence of the Liouville mode associated to the boundary degrees of freedom of 3-dimensional anti-de-Sitter geometries.
TL;DR: In this paper, the authors considered a BRST doublet where the background field entered with a non-zero BRST transformation and showed that the resulting functional W bg has the same physical amplitudes as the original one.
TL;DR: In this paper, the restrictions imposed by anomaly cancellation on the chiral fermion content of nonsupersymmetric gauge theories based on various groups are studied in spacetime dimension $D=6,$ 8, and 10.
Abstract: The restrictions imposed by anomaly cancellation on the chiral fermion content of nonsupersymmetric gauge theories based on various groups are studied in spacetime dimension $D=6,$ 8, and 10. In particular, we show that the only mathematically consistent chiral $\mathrm{SU}(5)$ theory in $D=6$ contains three nonidentical generations.
TL;DR: A family with Klippel-Feil anomaly, Sprengel anomaly, omovertebral bone, thumb abnormalities, and flexion-crease abnormalities is reported, concluding that this set of anomalies is a novel combination, probably representing pleiotropy of a single Mendelian gene.
Abstract: We report on a family with Klippel-Feil anomaly (KF), Sprengel anomaly, omovertebral bone, thumb abnormalities, and flexion-crease abnormalities. This combination of abnormalities does not fit into Holt-Oram syndrome, Wildervanck syndrome, oculo-auriculo-vertebral (Goldenhar) anomaly, or the VATER complex. Clinical aspects of a KF classification are discussed. The state of molecular research on KF is briefly reported. We conclude that this set of anomalies is a novel combination, probably representing pleiotropy of a single Mendelian gene.