θ–PHYSICS: 0–vacuum versus π–vacuum

2003 ◽  
Vol 18 (33n35) ◽  
pp. 2303-2310 ◽  
Author(s):  
M. Aguado ◽  
M. Asorey ◽  
D. García-Alvarez
Keyword(s):  
Symmetry Breaking ◽  
Vacuum Energy ◽  
Vacuum Energy Density ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Nodal Structure ◽  
First Order ◽  
Schrödinger Representation ◽  
Low Energies ◽  
Cp Symmetry

The behaviour of 0–vacuum and π–vacuum under CP symmetry is analyzed in two different families of quantum field theories: gauge theories in 4D and [Formula: see text] sigma models in 2D. In particular, the possibility of spontaneous CP symmetry breaking is analyzed by new continuum non-perturbative techniques. In the case of θ = 0–vacuum we find that the dependence of the vacuum energy density on θ around θ = 0 has not a first order cusp singularity, a missing requirement of the proof of the Vafa-Witten theorem. The result is based on the absence of Lee-Yang singularities for pure imaginary values of the θ–parameter. In the case of θ = π the result follows from the analysis of the nodal structure of the vacuum functional in the Schrödinger representation. The dynamics of both theories favors the localization of vacuum nodes at sphalerons instead of classical vacua as corresponds to parity even states. The existence of a dynamical level repulsion between parity even and parity odd states at low energies is the mechanism behind the absence of CP symmetry breaking in π–vacuum.

scholarly journals ISSUES WITH VACUUM ENERGY AS THE ORIGIN OF DARK ENERGY

2012 ◽  
Vol 27 (27) ◽  
pp. 1250154 ◽  
Author(s):  
HOURI ZIAEEPOUR
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Dark Energy ◽  
Particle Physics ◽  
Vacuum Energy ◽  
A Priori ◽  
Higgs Field ◽  
Scalar Fields ◽  
Vacuum Energy Density ◽  
Quantum Field

In this paper, we address some of the issues raised in the literature about the conflict between a large vacuum energy density, a priori predicted by quantum field theory, and the observed dark energy which must be the energy of vacuum or include it. We present a number of arguments against this claim and in favor of a null vacuum energy. They are based on the following arguments: A new definition for the vacuum in quantum field theory as a frame-independent coherent state; results from a detailed study of condensation of scalar fields in Friedmann–Lemaître–Robertson–Walker (FLRW) background performed in a previous work; and our present knowledge about the Standard Model of particle physics. One of the predictions of these arguments is the confinement of nonzero expectation value of Higgs field to scales roughly comparable with the width of electroweak gauge bosons or shorter. If the observation of Higgs by the LHC is confirmed, accumulation of relevant events and their energy dependence in near future should allow us to measure the spatial extend of the Higgs condensate.

scholarly journals The classical geometrization of the electromagnetism

2015 ◽  
Vol 12 (09) ◽  
pp. 1560022 ◽  
Author(s):  
Celso de Araujo Duarte
Keyword(s):  
General Relativity ◽  
Magnetic Monopoles ◽  
Electromagnetic Theory ◽  
Field Theories ◽  
Quantum Field Theories ◽  
Unified Theory ◽  
Quantum Field ◽  
Order Of Approximation ◽  
First Order ◽  
The 19Th Century

Following the line of the history, if by one side the electromagnetic theory was consolidated on the 19th century, the emergence of the special and the general relativity theories on the 20th century opened possibilities of further developments, with the search for the unification of the gravitation and the electromagnetism on a single unified theory. Some attempts to the geometrization of the electromagnetism emerged in this context, where these first models resided strictly on a classical basis. Posteriorly, they were followed by more complete and embracing quantum field theories. The present work reconsiders the classical viewpoint, with the purpose of showing that at first-order of approximation the electromagnetism constitutes a geometric structure aside other phenomena as gravitation, and that magnetic monopoles do not exist at least up to this order of approximation. Even though being limited, the model is consistent and offers the possibility of an experimental test of validity.

scholarly journals BAGS AND CONFINEMENT GOVERNED BY SPONTANEOUS SYMMETRY BREAKING OF SCALE INVARIANCE

2010 ◽  
Vol 25 (22) ◽  
pp. 4195-4220 ◽  
Author(s):  
E. I. GUENDELMAN
Keyword(s):  
Energy Density ◽  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Gauge Field ◽  
Scale Invariance ◽  
Vacuum Energy ◽  
Equations Of Motion ◽  
Flat Space ◽  
Vacuum Energy Density ◽  
Conformally Invariant

A general coordinate invariant theory is constructed where confinement of gauge fields and gauge dynamics in general is governed by the spontaneous symmetry breaking (s.s.b.) of scale invariance. The model uses two measures of integration in the action, the standard [Formula: see text] where g is the determinant of the metric and another measure Φ independent of the metric. To implement scale invariance, a dilaton field is introduced. Using the first-order formalism, curvature (ΦR and [Formula: see text]) terms, gauge field term ([Formula: see text] and [Formula: see text]) and dilaton kinetic terms are introduced in a conformally invariant way. Exponential potentials for the dilaton break down (softly) the conformal invariance down to global scale invariance, which also suffers s.s.b. after integrating the equations of motion. The model has a well-defined flat space limit. As a result of the s.s.b. of scale invariance phases with different vacuum energy density appear. Inside the bags, that is in the regions of larger vacuum energy density, the gauge dynamics is normal, that is nonconfining, while for the region of smaller vacuum energy density, the gauge field dynamics is confining. Likewise, the dynamics of scalars, like would be Goldstone bosons, is suppressed inside the bags.

scholarly journals ERG AND SCHWINGER-DYSON EQUATIONS – COMPARISON IN FORMULATIONS AND APPLICATIONS –

2001 ◽  
Vol 16 (11) ◽  
pp. 1913-1925 ◽  
Author(s):  
HARUHIKO TERAO
Keyword(s):  
Symmetry Breaking ◽  
Phase Structure ◽  
Three Dimensional ◽  
Dynamical Symmetry ◽  
Field Theories ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Practical Application ◽  
Dynamical Symmetry Breaking ◽  
Large N

The advantageous points of ERG in applications to non-perturbative analyses of quantum field theories are discussed in comparison with the Schwinger-Dyson equations. First we consider the relation between these two formulations specially by examining the large N field theories. In the second part we study the phase structure of dynamical symmetry breaking in three dimensional QED as a typical example of the practical application.

scholarly journals EXACT SOLUTIONS TO QUANTUM FIELD THEORIES AND INTEGRABLE EQUATIONS

1996 ◽  
Vol 11 (14) ◽  
pp. 1169-1183 ◽  
Author(s):  
A. MARSHAKOV
Keyword(s):  
Exact Solutions ◽  
Gauge Field ◽  
Integrable Systems ◽  
Gauge Field Theories ◽  
Field Theories ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Integrable Equations ◽  
First Order

The exact solutions to quantum string and gauge field theories are discussed and their formulation in the framework of integrable systems is presented. In particular we consider in detail several examples of the appearance of solutions to the first-order integrable equations of hydrodynamical type and stress that all known examples can be treated as partial solutions to the same problem in the theory of integrable systems.

scholarly journals On the Evaluation of Vacuum Energy Density in Quantum Field Theory

2021 ◽  
Author(s):  
Ervin Goldfain
Keyword(s):  
Energy Density ◽  
Vacuum Energy ◽  
Textbook Analysis ◽  
Harmonic Oscillators ◽  
Vacuum Energy Density ◽  
Model Parameters ◽  
Quantum Field ◽  
Quantum Vacuum ◽  
Flat Spacetime ◽  
The Standard Model

The textbook analysis of vacuum energy density (VED) in flat spacetime follows from Pauli’s lectures of 1951, in which quantum vacuum is modeled as a reservoir of free harmonic oscillators. In his lectures, Pauli shows that deriving a nearly vanishing VED is contingent upon fulfilling three corollary conditions called polynomial-in-mass-constraints. The goal of this work is to evaluate Pauli’s constraints against the Standard Model parameters and the Higgs mechanism of spontaneous symmetry breaking.

scholarly journals Deformations of supergravity and supersymmetry anomalies

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Markus B. Fröb ◽  
Camillo Imbimbo ◽  
Nicolò Risso
Keyword(s):  
A Priori ◽  
Functional Space ◽  
Full Detail ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
First Order ◽  
Brst Operator ◽  
Minimal Supergravity ◽  
Matter Theory

Abstract We present a BRST analysis of supersymmetry anomalies of $$ \mathcal{N} $$ N = 1 supersymmetric quantum field theories with anomalous R symmetry. To this end, we consider the coupling of the matter theory to classical $$ \mathcal{N} $$ N = 1 new minimal supergravity. We point out that a supersymmetry anomaly cocycle associated to the U(1)R field does exist for this theory. It is non-trivial in the space of supergravity fields (and ghosts), but it becomes BRST-exact in the functional space that includes antifields. Equivalently, the U(1)R supersymmetry anomaly cocycle vanishes “on-shell”. It is therefore removable. However, to remove it — precisely because it is not trivial in the smaller space of fields — one needs to deform the supergravity BRST operator. This deformation is triggered, at first order in the anomaly coefficient, by a local operator S1 of ghost number 1. We give a cohomological characterization of S1 and compute it in full detail. At higher orders in the anomaly coefficient, we expect a priori that further deformations of the BRST rules are necessary.

scholarly journals NONSINGULAR ORIGIN OF THE UNIVERSE AND THE COSMOLOGICAL CONSTANT PROBLEM

2011 ◽  
Vol 20 (14) ◽  
pp. 2767-2771 ◽  
Author(s):  
E. I. GUENDELMAN
Keyword(s):  
Vacuum Energy ◽  
Zero Point ◽  
Vacuum Energy Density ◽  
Cosmological Constant Problem ◽  
Static Universe ◽  
First Order ◽  
Present Universe ◽  
Einstein Static Universe ◽  
The Universe ◽  
Origin Of The Universe

We consider a nonsingular origin for the universe starting from an Einstein static universe in the framework of a theory which uses two volume elements [Formula: see text] and Φd4x, where Φ is a metric independent density, also curvature, curvature square terms, first order formalism and for scale invariance a dilaton field ϕ are considered in the action. In the Einstein frame we also add a cosmological term that parametrizes the zero point fluctuations. The resulting effective potential for the dilaton contains two flat regions, for ϕ → ∞ relevant for the nonsingular origin of the universe and ϕ → -∞, describing our present universe. Surprisingly, avoidance of singularities and stability as ϕ → ∞ imply a positive but small vacuum energy as ϕ → -∞. Zero vacuum energy density for the present universe is the "threshold" for universe creation.

scholarly journals Cosmology from a running vacuum model driven by a scalar field

2020 ◽  
Vol 17 (01) ◽  
pp. 2050016
Author(s):  
J. R. L. Santos ◽  
P. H. R. S. Moraes
Keyword(s):  
Scalar Field ◽  
Vacuum Energy ◽  
Equations Of Motion ◽  
Cosmological Parameters ◽  
Vacuum Energy Density ◽  
Vacuum Model ◽  
First Order ◽  
Model Driven ◽  
Energy Formula ◽  
Physical Consequences

The possibility that the vacuum energy density [Formula: see text] is, indeed, varying in time, has been investigated lately from the running vacuum models perspective. Motivated by such models, in this work, we relate the decaying vacuum energy [Formula: see text] with a scalar field [Formula: see text]. We derive the equations of motion from such a premise and implement the first-order formalism in order to obtain analytical solutions to the cosmological parameters. We show that these are in agreement with recent Planck observational data. We discuss the physical consequences of having [Formula: see text] related to [Formula: see text].

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