Showing papers in "Modern Physics Letters A in 1990"
TL;DR: In this paper, a field theoretic formulation for one-dimensional string theory is given by the collective field representation of the matrix model and leads to a physical interpretation of the theory as that of a massless scalar field in two dimensions.
Abstract: We describe a field theoretic formulation for one-dimensional string theory. It is given by the collective field representation of the matrix model and leads to a physical interpretation of the theory as that of a massless scalar field in two dimensions. The additional dimension, coming from the large-N color of the matrix model, has an extent which goes to infinity in the continuum limit. The interactions of the field theory are non-zero only at the boundaries of this additional dimension.
339 citations
TL;DR: In this article, it was shown that non-orientability of the manifold is equivalent to its non-compactness, and the physical quantities are directly expressed through geometrical characteristics of a manifold and gauge group parameters (Casimir eigenvalues and dimensions of the irreducible representations).
Abstract: Loop averages and partition functions in the U(N) gauge theory are calculated for loops without intersections on arbitrary two-dimensional manifolds including nonorientable ones. The physical quantities are directly expressed through geometrical characteristics of a manifold (areas enclosed by loops and the genus) and gauge group parameters (Casimir eigenvalues and dimensions of the irreducible representations). It is shown that, from the physical quantities’ point of view, non-orientability of the manifold is equivalent to its non-compactness.
252 citations
TL;DR: In this article, it was shown that under a suitable redefinition of the energy-momentum tensor, the central charge of N = 2 superconformal field theory vanishes and the theory is transformed into a topological quantum field theory.
Abstract: We present simple observations on the topological nature of N=2 superconformal field theories. We point out that under a suitable redefinition of the energy-momentum tensor the central charge of N=2 theory vanishes and the theory is transformed into a topological quantum field theory. BRST invariant observables are given by chiral primary fields. We also discuss the relevant perturbations of N=2 and SU(2) coset models.
237 citations
TL;DR: In this paper, the authors present the loop equations of motion which define the correlation functions for loop operators in two-dimensional quantum gravity and show that non-perturbative correlation functions constructed from real solutions of the Painleve equation of the first kind violate these equations by nonperturbation terms.
Abstract: We present the loop equations of motion which define the correlation functions for loop operators in two-dimensional quantum gravity. We show that non-perturbative correlation functions constructed from real solutions of the Painleve equation of the first kind violate these equations by non-perturbative terms.
222 citations
TL;DR: In this paper, the authors consider strings with an N = 2 local superconformal symmetry on the worldsheet and show that a Kahler function giving rise to self-dual gravity is the only physical degree of freedom of this theory.
Abstract: We consider strings with an N=2 local superconformal symmetry on the worldsheet. The critical dimension for this theory is four (two complex dimensions) with the signature (2, 2). A Kahler function giving rise to self-dual gravity is the only physical degree of freedom of this theory. Some miraculous symmetries are observed corresponding to the exchange of worldsheet and target moduli. The open and heterotic versions of this string theory correspond to self-dual Yang-Mills fields coupled to self-dual gravity in four dimensions.
204 citations
TL;DR: In this article, the antifield-antibracket formalism for quantization of gauge theories is discussed and the geometrical meaning of the antields, the geometric meaning of antibracket, and the operator Δ that appears in the quantum correction to the master equation are clarified.
Abstract: Certain aspects of the antifield-antibracket formalism for quantization of gauge theories are clarified. In particular, we discuss the geometrical meaning of the antifields, the geometric meaning of the antibracket, and the geometric meaning of the operator Δ that appears in the quantum correction to the master equation. Finally, we point out that the antibracket formalism contains most of the ingredients that would be needed to formulate an abstract Chern-Simons Lagrangian, as in open string field theory.
194 citations
TL;DR: In this article, a re-evaluation of the massless three-loop next-to-leading QCD correction to the correlator of the quark scalar currents and Γtot(H0 → hadrons) is presented.
Abstract: Analytical results of a re-evaluation of the massless three-loop next-to-leading QCD correction to the correlator of the quark scalar currents and Γtot(H0 → hadrons) are presented. The states of some other QCD perturbative results is discussed.
186 citations
TL;DR: In this article, the Schrodinger equation for the one-dimensional harmonic oscillator was considered, with the normal derivative replaced by a q-derivative, and normalizable solutions were found and the q-generalization of the Hermite polynomials was given.
Abstract: We consider the Schrodinger equation for the one-dimensional harmonic oscillator, but with the normal derivative replaced by a q-derivative. The normalizable solutions are found and the q-generalization of the Hermite polynomials is given. The free equation is also considered, but no normalizable eigenstates exist even if the system is in a box.
159 citations
TL;DR: In this paper, the properties of the loop equations for the N × N Hermitian matrix model with arbitrary (even) interaction as well as of their continuum limit associated with the two-dimensional quantum gravity were studied.
Abstract: We study the properties of the loop equations for the N × N Hermitian matrix model with arbitrary (even) interaction as well as of their continuum limit, associated with the two-dimensional quantum gravity. We apply the general procedure of iterative solution proposed recently by David. We relate the specific heat to the singular behavior of the connected correlator of two loops. We solve the continuum equation to a few lower orders in the string coupling constant, obtaining results for macroscopic loops including the case of a multicritical fixed point.
121 citations
TL;DR: In this paper, a nonperturbative formulation of 2D quantum gravity in terms of the large-N limit of matrix models is studied to include the effects of higher order curvature terms.
Abstract: The non-perturbative formulation of 2-dimensional quantum gravity in terms of the large-N limit of matrix models is studied to include the effects of higher order curvature terms. This leads to matrix models whose potential contains a symmetry breaking term of the form Tr ϕAϕA, where A is a given fixed matrix. This is studied in d = 0 dimensions and effectively induces additional terms of the form (Tr ϕk)2 in the one matrix potential. An exact solution to leading order of the potential V(ϕ) = 1/2 Tr ϕ2 + g/N Tr ϕ4 + g′/N2 (Tr ϕ2)2 is presented leading to 3 phases: γ = −1/2 (smooth surfaces), γ = 1/2 (branched polymer) and γ = 1/3 (intermediate phase). Including a Tr ϕ6 term in the potential gives rise to an additional phase with γ = 1/4. It is conjectured that for the general polynomial potential there are phases with γ = 1/n, n = 2, 3, …. The γ > 0 phases may correspond to c > 1 matter coupled to 2-dimensional gravity.
113 citations
TL;DR: In this article, the authors construct a realization of a deformation of the Lie algebra of a group in terms of the generators of the classical Lie algebra for arbitrary (odd) deforming functions.
Abstract: We construct a realization of a deformation of the Lie algebra of a group in terms of the generators of the classical Lie algebra of the group. The construction works for arbitrary (odd) deforming functions and, as a special case, it reproduces the standard quantum deformation of the algebra. For all these functions it gives a co-multiplication, that is, a group homomorphism, and provides an antipode and a co-unit. It therefore promotes any arbitrary deformation into a Hopf algebra.
TL;DR: In this paper, a method was developed for systematically constructing trigonometric and rational solutions of the Yang-Baxter equation using the representation theory of quantum supergroups, and new quantum R-matrices were obtained by applying the method to the vector representations of quantum osp(1/2) and gl(m/n).
Abstract: A method is developed for systematically constructing trigonometric and rational solutions of the Yang-Baxter equation using the representation theory of quantum supergroups. New quantum R-matrices are obtained by applying the method to the vector representations of quantum osp(1/2) and gl(m/n).
TL;DR: In this paper, the search for double beta-decay of 76Ge with half-life of T1/2(2v)=(9±1) · 1020 y was carried out with a detector fabricated of enriched material.
Abstract: The search for double beta-decay of 76Ge was carried out with a detector fabricated of enriched material (85% abundance of 76Ge compared with 7.8% natural abundance). Measurements have been performed by the ITEP/YePI team in the Avan salt mine, 245 meters underground, situated in Yerevan, Armenia. Evidence for two-neutrino double beta-decay of 76Ge with half-life of T1/2(2v)=(9±1) · 1020 y was obtained. New limits for neutrinoless double beta-decay, T1/2(0v)>1.3×1024 y, and double beta-decay with majoron emission T1/2(0v, B)>1×1022 y were obtained at 68% CL from mean background fluctuations. Limit for 0v-decay derived by the maximum likelihood method was T1/2>2.0×1024 y.
Journal Article•
TL;DR: In this paper, the authors quantized the Liouville theory and quantum supergravity in the conformal gauge, and explicitly calculated the Jacobian accompanying the change from the Weyl invariant measure to the translation invariant one.
Abstract: We quantize the Liouville theory, or 2-D quantum gravity, and quantum supergravity in the conformal gauge. We explicitly calculate the Jacobian accompanying the change from the Weyl invariant measure to the translation invariant one. We show that it is of the same form as the original Liouville action, thus establishing a conjecture of David and Distler and Kawai. This calculation yields dressed gravitational central charges and anomalous dimensions from first principles.
TL;DR: In this article, the evolution of a scalar field interacting with an environment in the de Sitter phase of an inflationary universe is studied, and it is shown that the coherence length of the quantum fluctuations rapidly decreases after the wavelength of the perturbation crosses the Hubble radius.
Abstract: The evolution of a scalar field interacting with an environment in the de Sitter phase of an inflationary Universe is studied. The environment is taken to be a second scalar field. It is shown that the coherence length of the quantum fluctuations rapidly decreases after the wavelength of the perturbation crosses the Hubble radius. Hence, the fluctuations can be interpreted as classical. This lends support to the usual derivation of the spectrum of density perturbations in inflationary Universe models.
TL;DR: In this article, the authors review recent advances in the theoretical understanding of electric charge quantization in the Standard Model and some of its extensions and discuss the roles played by classical constraints, gauge and mixed gauge-gravitational anomaly cancellation and the demand of vector-like electromagnetic interactions.
Abstract: We review recent advances in the theoretical understanding of electric charge quantization in the Standard Model and some of its extensions. We discuss the roles played by classical constraints, gauge and mixed gauge-gravitational anomaly-cancellation and the demand of vector-like electromagnetic interactions. An attempt is made to clearly explain and contrast the points of view of various authors.
TL;DR: In this paper, it was pointed out that if we assume U(3)-family nonet Higgs scalars which couple to charged leptons bilinearly, a simple Higgs potential with a term which breaks the U( 3)-family into SU( 3]-family will lead to a mass sum rule.
Abstract: It is pointed out that if we assume U(3)-family nonet Higgs scalars which couple to charged leptons bilinearly, a simple Higgs potential with a term which breaks the U(3)-family into SU(3)-family will lead to a mass sum rule, $m_e +m_\mu +m_\tau =(2/3) (\sqrt{m_e} +\sqrt{m_\mu} +\sqrt{m_\tau})^2$. This sum rule is in excellent agreement with experiment. The sum rule is also in good agreement with experiment when applied to the masses of down-quarks, d, s, and b.
TL;DR: In this article, the Batalin-Vilkovisky procedure for the BRST invariant path-integral quantization of general gauge theories is discussed and an extension of this is given in which a path integral is constructed that is invariant under an anti-BRST symmetry as well as the BRst symmetry.
Abstract: The Batalin-Vilkovisky procedure for the BRST invariant path-integral quantization of general gauge theories is discussed. An extension of this is given in which a path integral is constructed that is invariant under an anti-BRST symmetry as well as the BRST symmetry. It is also manifestly invariant under an Sp(2) symmetry which rotates the BRST and anti-BRST charges into one another.
TL;DR: In this article, it was shown that the 3-flavor strange-quark-matter (3-FLM) is as likely a ground state as the confined hadronic phase of nucleons and nuclei.
Abstract: The world's data on radio pulsars are not expected to represent the underlying pulsar population because of a search bias against detection of short periods, especially below 1 ms. Yet pulsars in increasing numbers with periods right down to this limit have been discovered, suggesting that there may be even shorter ones. If pulsars with periods below 1/2 ms were found, the conclusion that the confined hadronic phase of nucleons and nuclei is only metastable would be almost inescapable. The plausible ground state in that event is the deconfined phase of (3-flavor) strange-quark-matter. From the QCD energy scale this is as likely a ground state as the confined phase. We show that strange matter as the ground state is not ruled out by any known fact, and most especially not by the fact that the universe is in the confined phase.
TL;DR: In this paper, it was shown that the 2-d coset models SU(p + 1)N/SU(p)N ⊗ U(1) provide unitary representations of the chiral operator algebra W∞ in the large level (N → ∞) limit, with central charge c = 2p.
Abstract: It is shown that the 2 – d coset models SU(p + 1)N/SU(p)N ⊗ U(1) provide unitary representations of the chiral operator algebra W∞ in the large level (N → ∞) limit, with central charge c = 2p. For p ≥ 2, the corresponding field theories possess additional symmetries which given rise to a U(p) matrix generalization of W∞, denoted by $W_\infty^p$. Its commutation relations are obtained in closed form for all values of p and W∞ is identified with the U(1) trace part of $W_\infty^p$. It is also shown that $W_\infty^p$ at large p is associated with the algebra of symplectic diffeomorphisms in four dimensions.
TL;DR: In this paper, the argument that the decay νi→νj+ϕ is suppressed in triplet majoron models by lepton number conservation is re-examined.
Abstract: The argument that the decay νi→νj+ϕ is suppressed in triplet majoron models by lepton number conservation is re-examined. It is found that in general the decay rates for νi→νj+ϕ and for $
u _i \to \bar
u _j + \phi $ should be of comparable magnitudes.
TL;DR: In this article, it was shown that all higher genus minimal area string diagrams can be built using vertices and propagators, implying that the off-shell amplitudes arise from the Feynman rules of a full quantum theory of closed strings.
Abstract: Canonical and factorizable off-shell amplitudes for covariant closed string theory can be obtained from string diagrams of minimal area. Evidence is given that all higher genus minimal area string diagrams can be built using vertices and propagators, implying that the off-shell amplitudes arise from the Feynman rules of a full quantum theory of closed strings. The quantum action gives an exact solution of the full master equation of Batalin and Vilkoviski.
TL;DR: In this article, the authors investigate unitary one-matrix models described by polynomial potentials and find many different phases of these models at strong, weak and intermediate couplings characterized by multiple gaps in the spectral density.
Abstract: We investigate unitary one-matrix models described by polynomial potentials. We find many different phases of these models at strong, weak and intermediate couplings characterized by multiple gaps in the spectral density. The one-gap phase is studied in detail and it shows multi-critical behavior with γ = −1/m. The multiple-phase structure may have implications for the phases of string theory.
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TL;DR: In this paper, consistent quantization determines the renormalization of couplings in a quantum field theory coupled to gravity in two dimensions, where the dynamical degree of freedom of the two-dimensional metric plays the role of time in target space.
Abstract: We show how consistent quantization determines the renormalization of couplings in a quantum field theory coupled to gravity in two dimensions. The special status of couplings corresponding to conformally invariant matter is discussed. In string theory, where the dynamical degree of freedom of the two-dimensional metric plays the role of time in target space, these renormalization group equations are themselves the classical equations of motion. Time independent solutions, like classical vacuua, correspond to the situation in which matter is conformally invariant. Time dependent solutions, like tunnelling configurations between vacuua, correspond to special trajectories in theory space. We discuss an example of such a trajectory in the space containing the c < 1 minimal models. We also discuss the connection between this work and the recent attempts to construct non-perturbative string theories based on matrix models.
TL;DR: In this paper, the authors evaluate the rates and present the dynamical distributions for mH ≲ 1/2 MZ at high luminosity e+e− colliders at TeV energies.
Abstract: The production of two standard model Higgs bosons via the WW fusion process e+e− → would test the predicted HHH, HWW and HHWW couplings. At TeV energies this fusion cross section dominates over that from e+e− →ZHH and would give significant event rates for mH ≲ 1/2 MZ at high luminosity e+e− colliders. We evaluate the rates and present the dynamical distributions.
TL;DR: In this article, the Parisi-Marinari suggestion to treat 2D quantum gravity as ground state of the 1d supersymmetric string is elaborated in some detail, and the third order linear ordinary differential equation describing in the double scaling limit the distribution of eigenvalues of the random matrix (i.e., the Liouville field) is derived and studied numerically.
Abstract: The Parisi-Marinari suggestion to treat 2d quantum gravity as ground state of the 1d supersymmetric string is elaborated in some detail. The third order linear ordinary differential equation describing in the double scaling limit the distribution of eigenvalues of the random matrix (i.e., the Liouville field) is derived and studied numerically. Unlike the Painleve equation, our equation leads to continuous spectrum; however, the nonperturbative effects display themselves as quantum oscillations on top of smooth WKB distribution. Nonperturbative solution is free of any ambiguities.
TL;DR: In this paper, a defining set of commutation relations to a q-analogue of boson operator was proposed, and the explicit form of the number operator was given in terms of aq and its positive definiteness was proved.
Abstract: We propose a defining set of commutation relations to a q-analogue of boson operator; , and [N, aq]=−aq, which contracts to the Heisenberg algebra of boson operators in the limit of q=1. Here, N is the number operator, [N]q being its q-analogue operator. By making use of this set, we construct a new realization of the “noncompact” quantum group SUq(1, 1) in addition to that of the SUq(2) recently proposed by Biedenharn. The explicit form of the number operator is given in terms of aq and and its positive definiteness is proved. A uniqueness of our commutators is also discussed. It is shown that the quantum group SUq(2) appears as a true symmetry group of a q-analogue of the two-dimensional harmonic oscillator and the SUq(1, 1) as its dynamical group.