scholarly journals Dirac procedure and the Hamiltonian formalism for cosmological perturbations in a Bianchi I universe

2021 ◽  
Author(s):  
Alice Boldrin ◽  
Przemyslaw Malkiewicz
Keyword(s):  
Gravitational Wave ◽  
Hamiltonian Formalism ◽  
Canonical Formalism ◽  
Constrained Systems ◽  
Anisotropic Universe ◽  
Cosmological Perturbations ◽  
Bianchi I ◽  
Starting Point ◽  
Gauge Fixing ◽  
Metric Perturbation

Abstract We apply the Dirac procedure for constrained systems to the Arnowitt-Deser-Misner formalism linearized around the Bianchi I universe. We discuss and employ basic concepts such as Dirac observables, Dirac brackets, gauge-fixing conditions, reduced phase space, physical Hamiltonian, canonical isomorphism between different gauge-fixing surfaces and spacetime reconstruction. We relate this approach to the gauge-fixing procedure for non-perturbative canonical relativity. We discuss the issue of propagating a basis for the scalar-vector-tensor decomposition as, in an anisotropic universe, the wavefronts of plane waves undergo a non-trivial evolution. We show that the definition of a gravitational wave as a traceless-transverse mode of the metric perturbation needs to be revised. Moreover there exist coordinate systems in which a polarization mode of the gravitational wave is given entirely in terms of a scalar metric perturbation. We first develop the formalism for the universe with a single minimally coupled scalar field and then extend it to the multi-field case. The obtained fully canonical formalism will serve as a starting point for a complete quantization of the cosmological perturbations and the cosmological background.

scholarly journals Finite BRST–anti-BRST transformations in generalized Hamiltonian formalism

2014 ◽  
Vol 29 (27) ◽  
pp. 1450159 ◽  
Author(s):  
Pavel Yu. Moshin ◽  
Alexander A. Reshetnyak
Keyword(s):  
Dynamical Systems ◽  
Path Integral ◽  
Hamiltonian Path ◽  
Hamiltonian Formalism ◽  
Lagrangian Formalism ◽  
Yang Mills ◽  
Gauge Dependence ◽  
Field Dependent ◽  
Gauge Fixing ◽  
Constrained Dynamical Systems

We introduce the notion of finite BRST–anti-BRST transformations for constrained dynamical systems in the generalized Hamiltonian formalism, both global and field-dependent, with a doublet λa, a = 1, 2, of anticommuting Grassmann parameters and find explicit Jacobians corresponding to these changes of variables in the path integral. It turns out that the finite transformations are quadratic in their parameters. Exactly as in the case of finite field-dependent BRST–anti-BRST transformations for the Yang–Mills vacuum functional in the Lagrangian formalism examined in our previous paper [arXiv:1405.0790 [hep-th]], special field-dependent BRST–anti-BRST transformations with functionally-dependent parameters λa= ∫ dt(saΛ), generated by a finite even-valued function Λ(t) and by the anticommuting generators saof BRST–anti-BRST transformations, amount to a precise change of the gauge-fixing function for arbitrary constrained dynamical systems. This proves the independence of the vacuum functional under such transformations. We derive a new form of the Ward identities, depending on the parameters λaand study the problem of gauge dependence. We present the form of transformation parameters which generates a change of the gauge in the Hamiltonian path integral, evaluate it explicitly for connecting two arbitrary Rξ-like gauges in the Yang–Mills theory and establish, after integration over momenta, a coincidence with the Lagrangian path integral [arXiv:1405.0790 [hep-th]], which justifies the unitarity of the S-matrix in the Lagrangian approach.

scholarly journals Chiral perturbation theory for GR

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Kirill Krasnov ◽  
Yuri Shtanov
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation ◽  
Perturbative Calculation ◽  
New Formalism ◽  
Yang Mills ◽  
First Order ◽  
Starting Point ◽  
Gauge Fixing ◽  
New Perturbation ◽  
Effective Description

Abstract We describe a new perturbation theory for General Relativity, with the chiral first-order Einstein-Cartan action as the starting point. Our main result is a new gauge-fixing procedure that eliminates the connection-to-connection propagator. All other known first-order formalisms have this propagator non-zero, which significantly increases the combinatorial complexity of any perturbative calculation. In contrast, in the absence of the connection-to-connection propagator, our formalism leads to an effective description in which only the metric (or tetrad) propagates, there are only cubic and quartic vertices, but some vertex legs are special in that they cannot be connected by the propagator. The new formalism is the gravity analog of the well-known and powerful chiral description of Yang-Mills theory.

GENERAL COVARIANCE, TOPOLOGICAL QUANTUM FIELD THEORIES AND FRACTIONAL STATISTICS

1992 ◽  
Vol 07 (02) ◽  
pp. 209-234 ◽  
Author(s):  
J. GAMBOA
Keyword(s):  
Hamiltonian Formalism ◽  
Field Theories ◽  
General Covariance ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Fractional Statistics ◽  
Multiply Connected ◽  
Topological Quantum ◽  
Gauge Fixing ◽  
Topological Quantum Field Theories

Topological quantum field theories and fractional statistics are both defined in multiply connected manifolds. We study the relationship between both theories in 2 + 1 dimensions and we show that, due to the multiply-connected character of the manifold, the propagator for any quantum (field) theory always contains a first order pole that can be identified with a physical excitation with fractional spin. The article starts by reviewing the definition of general covariance in the Hamiltonian formalism, the gauge-fixing problem and the quantization following the lines of Batalin, Fradkin and Vilkovisky. The BRST–BFV quantization is reviewed in order to understand the topological approach proposed here.

scholarly journals Noether identities and gauge fixing the action for cosmological perturbations

2014 ◽  
Vol 89 (2) ◽  
Author(s):  
Macarena Lagos ◽  
Máximo Bañados ◽  
Pedro G. Ferreira ◽  
Sebastián García-Sáenz
Keyword(s):  
Cosmological Perturbations ◽  
Gauge Fixing

Bianchi-I cosmology within f(T): Reconstruction method and dynamical study

2020 ◽  
Vol 18 (01) ◽  
pp. 2150012
Author(s):  
C. Ainamon ◽  
M. G. Ganiou ◽  
H. F. Abadji ◽  
M. J. S. Houndjo
Keyword(s):  
Space Time ◽  
Anisotropic Fluid ◽  
Anisotropic Universe ◽  
Reconstruction Method ◽  
Dynamical Study ◽  
Bianchi I ◽  
Dynamical Behaviors ◽  
Modified Gravity Theories ◽  
Universe Evolution ◽  
Autonomous Dynamical System

This paper is fundamentally devoted to the cosmological reconstruction and dynamic studying in homogeneous BIANCHI-I space-time under the [Formula: see text] background. Its content is supported by the fact that in the General Relativity description of the standard cosmological paradigm, the evolution from an anisotropic universe into an Friedmann–Lemaitre–Robertson–Walker (FLRW) one can be achieved by a period of inflationary expansion. Nowadays, modified gravity theories like [Formula: see text] are widely accepted to provide a real description of some universe evolution phases like inflation era, matter-dominated era, etc. So, we aim to examine here what [Formula: see text] gravity model can accommodate with an anisotropic universe, an expanding universe and even the transition between both evolutions. To reach this goal, we use a reconstruction method based on dynamic equations in Bianchi-I space-time by assuming a particular form for the metric anisotropy and by specifying some time functions describing average scale factor. Most of the obtained models are consistent with certain known results in the literature but other add new results in this work. In the second part of this work, the dynamical behaviors of the Bianchi-I space-time are addressed through the reconstruction of an autonomous dynamical system. For an aleatory choice of anisotropic fluid, the numerical analysis of the system shows that the metric anisotropy decreases with expansion. Then, an attractor point is reached and becomes unstable by the end of inflation. Such interesting properties found in this work on Bianchi-I space-time are often interpreted as graceful exit from inflation which doesn’t occur in ordinary FLRW space-time.

scholarly journals HAMILTONIAN FORMALISM FOR BLACK HOLES AND QUANTIZATION II

1996 ◽  
Vol 05 (03) ◽  
pp. 227-250 ◽  
Author(s):  
MARCO CAVAGLIÀ ◽  
VITTORIO DE ALFARO ◽  
ALEXANDRE T. FILIPPOV
Keyword(s):  
Hilbert Space ◽  
Black Holes ◽  
Black Hole ◽  
Invariant Measure ◽  
Hamiltonian Formalism ◽  
Quantization Method ◽  
Schwarzschild Black Hole ◽  
Canonical Formulation ◽  
Gauge Fixing ◽  
Rigid Transformations

We quantize by the Dirac-Wheeler-DeWitt method the canonical formulation of the Schwarzschild black hole developed in a previous paper. We investigate the properties of the operators that generate rigid symmetries of the Hamiltonian, establish the form of the invariant measure under the rigid transformations, and determine the gauge fixed Hilbert space of states. We also prove that the reduced quantization method leads to the same Hilbert space for a suitable gauge fixing.

scholarly journals A systematic study of finite BRST-BFV transformations in Sp(2)-extended generalized Hamiltonian formalism

2014 ◽  
Vol 29 (23) ◽  
pp. 1450128 ◽  
Author(s):  
Igor A. Batalin ◽  
Peter M. Lavrov ◽  
Igor V. Tyutin
Keyword(s):  
Field Dependence ◽  
Path Integral ◽  
Systematic Study ◽  
Hamiltonian Formalism ◽  
Gauge Fixing ◽  
Compensation Equation

We study systematically finite BRST-BFV transformations in Sp(2)-extended generalized Hamiltonian formalism. We present explicitly their Jacobians and the form of a solution to the compensation equation determining the functional field dependence of finite Fermionic parameters, necessary to generate arbitrary finite change of gauge-fixing functions in the path integral.

HAMILTONIAN BRST QUANTIZATION OF CHERN-SIMONS GAUGE THEORY

1990 ◽  
Vol 05 (21) ◽  
pp. 1663-1670 ◽  
Author(s):  
Y. IGARASHI ◽  
H. IMAI ◽  
S. KITAKADO ◽  
J. KUBO ◽  
H. SO
Keyword(s):  
Gauge Theory ◽  
Brst Quantization ◽  
Hamiltonian Formalism ◽  
Constrained Systems ◽  
Three Dimensions ◽  
Brst Transformation ◽  
Abelian Gauge ◽  
Abelian Gauge Theory ◽  
Covariant Action ◽  
Chern Simons

We quantize non-abelian gauge theory with only a Chern-Simons term in three dimensions by using the generalized Hamiltonian formalism of Batalin and Fradkin for irreducible first-and second-class constrained systems, and derive a covariant action for the theory which is invariant under the off-shell nilpotent BRST transformation. Some aspects of the theory, finiteness and supersymmetry are discussed.

THE sp(3) BRST HAMILTONIAN FORMALISM FOR THE YANG–MILLS FIELDS

2008 ◽  
Vol 23 (10) ◽  
pp. 737-750 ◽  
Author(s):  
CARMEN IONESCU
Keyword(s):  
Brst Symmetry ◽  
Hamiltonian Formalism ◽  
General Rule ◽  
Extended Phase Space ◽  
Extended Phase ◽  
Yang Mills ◽  
First Approximation ◽  
Gauge Term ◽  
Generalized Symmetry ◽  
Gauge Fixing

The paper presents in all its nontrivial details the sp(3) BRST Hamiltonian formalism. It is based on structuring the extended phase space on many levels. In this picture, the standard BRST symmetry appears as being only the first approximation of a generalized symmetry, acting as a horizontal (same level) operator. The gauge-fixing problem is completely solved by formulating a theorem and a general rule which allow the choice of a simple gauge term. As an example, the Hamiltonian sp(3) quantization of the Yang–Mills model is exhaustively presented.

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