scholarly journals On the vacuum state in quantum field theory. II

1965 ◽  
Vol 1 (1) ◽  
pp. 57-79 ◽  
Author(s):  
H. J. Borchers
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Vacuum State ◽  
Quantum Field

scholarly journals Beyond Combination: How Cosmic Consciousness Grounds Ordinary Experience

2018 ◽  
Vol 4 (3) ◽  
pp. 390-410 ◽  
Author(s):  
ITAY SHANI ◽  
JOACHIM KEPPLER
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Vacuum State ◽  
Present Approach ◽  
Quantum Field ◽  
Eastern Philosophy ◽  
Stochastic Electrodynamics ◽  
Ordinary Experience ◽  
Wisdom Traditions ◽  
Ordinary Consciousness

AbstractThe aim of this paper is twofold. First, our purpose is to propose and motivate a novel and scientifically informed variant of cosmopsychism, namely, the view that the experiences of ordinary subjects are ultimately grounded in an all-pervading cosmic consciousness. Second, we will demonstrate that this approach generates promising avenues for addressing familiar problems of phenomenal constitution. We use stochastic electrodynamics (SED) as the physical bedrock of our approach, supplementing it with key insights about the nature of consciousness long emphasized in eastern philosophy and other wisdom traditions. We proceed to show that our approach substantiates an intriguing way of thinking about the dynamical emergence of ordinary consciousness from cosmic consciousness, identifying the latter with the vacuum state of quantum field theory. Finally, we argue that the present approach is well suited to address problems of phenomenal constitution, in particular as they pertain to the qualities and structure of experience and to the generation of subjects.

scholarly journals Locality and General Vacua in Quantum Field Theory

2021 ◽  
Author(s):  
Daniele Colosi ◽  
◽  
Robert Oeckl ◽  
◽  
◽  
...  
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Hilbert Space ◽  
Vacuum State ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Algebraic Quantum ◽  
Particle Pairs ◽  
The One ◽  
Gns Construction

We extend the framework of general boundary quantum field theory (GBQFT) to achieve a fully local description of realistic quantum field theories. This requires the quantization of non-Kähler polarizations which occur generically on timelike hypersurfaces in Lorentzian spacetimes as has been shown recently. We achieve this in two ways: On the one hand we replace Hilbert space states by observables localized on hypersurfaces, in the spirit of algebraic quantum field theory. On the other hand we apply the GNS construction to twisted star-structures to obtain Hilbert spaces, motivated by the notion of reflection positivity of the Euclidean approach to quantum field theory. As one consequence, the well-known representation of a vacuum state in terms of a sea of particle pairs in the Hilbert space of another vacuum admits a vast generalization to non-Kähler vacua, particularly relevant on timelike hypersurfaces.

POINCARÉ INVARIANCE AND QUANTUM PARASUPERFIELDS

1993 ◽  
Vol 08 (28) ◽  
pp. 5041-5061 ◽  
Author(s):  
J. BECKERS ◽  
N. DEBERGH
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Arbitrary Order ◽  
Vacuum State ◽  
Unitary Representations ◽  
Quantum Field ◽  
Irreducible Unitary Representations ◽  
Casimir Operators ◽  
Zumino Model

Parasupersymmetries of arbitrary order p of paraquantization are seen in quantum field theory by requiring Poincaré invariance in the N=1, D=4 Context. We construct the corresponding minimal Lie parasuperalgebra as well as its (two) Casimir operators. Through its little parasuperalgebra in the timelike case, we characterize the irreducible (unitary) representations by constructing a generalized vacuum state with its partners. In the first nontrivial case, p=2, we realize the operators in terms of para-Grassmannian variables and deduce parasupersymmetric equations leading to relativistic descriptions of spin 0, 1/2 and 1 (para)particles by considering parasuperfields and their para-Grassmannian components. In fact, we consider two nonequivalent realizations leading respectively to free and interacting relativistic descriptions, the latter corresponding to the extension of the Wess-Zumino model in this parasupercontext. The inclusion of symmetries and supersymmetries in the parasupersymmetries is enhanced.

scholarly journals ON THE EXISTENCE OF KINK (SOLITON) STATES

1996 ◽  
Vol 08 (08) ◽  
pp. 1187-1203 ◽  
Author(s):  
DIRK SCHLINGEMANN
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Vacuum State ◽  
Quantum Field ◽  
Algebraic Quantum Field Theory ◽  
Algebraic Quantum ◽  
Vacuum States ◽  
Text Model ◽  
Kink Soliton ◽  
Natural Way

Several two-dimensional quantum field theory models have more than one vacuum state. Familiar examples are the Sine-Gordon and the [Formula: see text]-model. It is known that in these models there are also states, called soliton or kink states, which interpolate different vacua. We investigate the following question: Which are the properties a pair of vacuum states must have, such that an interpolating kink state can be constructed? We discuss the problem in the framework of algebraic quantum field theory which includes, for example, the P(ϕ)2-models. We identify a large class of vacuum states, including the vacua of the P(ϕ)2-models, for which there is a natural way to construct an interpolating kink state.

Article

1998 ◽  
Vol 76 (2) ◽  
pp. 111-127
Author(s):  
D Solomon
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Gauge Invariance ◽  
Vacuum State ◽  
Dirac Field ◽  
Quantum Field ◽  
Gauge Invariant ◽  
Definition Of ◽  
The Way

Quantum field theory is assumed to be gauge invariant. We show that for a Dirac field the assumption of gauge invariance impacts on the way the vacuum state is defined, and also that the conventional definition of the vacuum state must be modified to take into account the requirements of gauge invariance.PACS No. 1100

scholarly journals QUANTUM FIELD THEORY IN CURVED SPACE–TIME, THE OPERATOR PRODUCT EXPANSION, AND DARK ENERGY

2008 ◽  
Vol 17 (13n14) ◽  
pp. 2607-2615 ◽  
Author(s):  
STEFAN HOLLANDS ◽  
ROBERT M. WALD
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Operator Product Expansion ◽  
Vacuum Expectation ◽  
Vacuum State ◽  
Space Time ◽  
Operator Product ◽  
Energy Tensor ◽  
Quantum Field ◽  
Curved Space

To make sense of quantum field theory in an arbitrary (globally hyperbolic) curved space–time, the theory must be formulated in a local and covariant manner in terms of locally measureable field observables. Since a generic curved space–time does not possess symmetries or a unique notion of a vacuum state, the theory also must be formulated in a manner that does not require symmetries or a preferred notion of a "vacuum state" and "particles". We propose such a formulation of quantum field theory, wherein the operator product expansion (OPE) of the quantum fields is elevated to a fundamental status, and the quantum field theory is viewed as being defined by its OPE. Since the OPE coefficients may be better behaved than any quantities having to do with states, we suggest that it may be possible to perturbatively construct the OPE coefficients — and, thus, the quantum field theory. By contrast, ground/vacuum states — in space–times, such as Minkowski space–time, where they may be defined — cannot vary analytically with the parameters of the theory. We argue that this implies that composite fields may acquire nonvanishing vacuum state expectation values due to nonperturbative effects. We speculate that this could account for the existence of a nonvanishing vacuum expectation value of the stress-energy tensor of a quantum field occurring at a scale much smaller than the natural scales of the theory.

scholarly journals Listening to the quantum vacuum: a perspective on the dynamical Casimir effect

2020 ◽  
Vol 51 (4) ◽  
pp. 18-20
Author(s):  
Gheorghe Sorin Paraoanu ◽  
Göran Johansson
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Experimental Verification ◽  
Casimir Effect ◽  
Empty Space ◽  
Vacuum State ◽  
Quantum Field ◽  
Quantum Vacuum ◽  
Dynamical Casimir Effect ◽  
Virtual Particles

Modern quantum field theory has offered us a very intriguing picture of empty space. The vacuum state is no longer an inert, motionless state. We are instead dealing with an entity teeming with fluctuations that continuously produce virtual particles popping in and out of existence. The dynamical Casimir effect is a paradigmatic phenomenon, whereby these particles are converted into real particles (photons) by changing the boundary conditions of the field. It was predicted 50 years ago by Gerald T. Moore and it took more than 40 years until the first experimental verification.

scholarly journals Quantum unitary dynamics of a charged fermionic field and Schwinger effect

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Álvaro Álvarez-Domínguez ◽  
Luis J. Garay ◽  
David García-Heredia ◽  
Mercedes Martín-Benito
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Particle Creation ◽  
Vacuum State ◽  
Time Dependent ◽  
Quantum Field ◽  
Homogeneous Electric Field ◽  
Fermionic Field ◽  
Translational Invariance ◽  
Definition Of

Abstract In quantum field theory, particle creation occurs, in general, when an intense external field, such as an electromagnetic field, breaks time translational invariance. This leads to an ambiguity in the definition of the vacuum state. In cosmological backgrounds this ambiguity has been reduced by imposing that the quantization preserves the symmetries of the system and that the dynamics is unitarily implemented. In this work, we apply these requirements to the quantization of a massive charged fermionic field coupled to a classical time-dependent homogeneous electric field, extending previous studies done for a scalar field. We characterize the quantizations fulfilling the criteria above and we show that they form a unique equivalence class of unitarily related quantizations, which provide a well-defined number of created particles at all finite times.

scholarly journals Construction of Kink Sectors for Two-Dimensional Quantum Field Theory Models – An Algebraic Approach

1998 ◽  
Vol 10 (06) ◽  
pp. 851-891 ◽  
Author(s):  
Dirk Schlingemann
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Algebraic Approach ◽  
Vacuum State ◽  
Quantum Field ◽  
Two Dimensional ◽  
Algebraic Quantum ◽  
Free Scalar ◽  
Split Property ◽  
Text Model

Several two-dimensional quantum field theory models have more than one vacuum state. Familiar examples are the Sine-Gordon and the [Formula: see text]-model. It is known that in these models there are also states, called kink states, which interpolate different vacua. A general construction scheme for kink states in the framework of algebraic quantum field theory is developed in a previous paper. However, for the application of this method, the crucial condition is the split property for wedge algebras in the vacuum representations of the considered models. It is believed that the vacuum representations of P(ϕ)2-models fulfill this condition, but a rigorous proof is only known for the massive free scalar field. Therefore, we investigate in a construction of kink states which can directly be applied to a large class of quantum field theory models, by making use of the properties of the dynamics of a P(ϕ)2 and Yukawa2 models.

scholarly journals GEOMETRIC MODULAR ACTION FOR DISJOINT INTERVALS AND BOUNDARY CONFORMAL FIELD THEORY

2010 ◽  
Vol 22 (03) ◽  
pp. 331-354 ◽  
Author(s):  
ROBERTO LONGO ◽  
PIERRE MARTINETTI ◽  
KARL-HENNING REHREN
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Conformal Field Theory ◽  
Modular Group ◽  
Vacuum State ◽  
Quantum Field ◽  
Conformal Field ◽  
Local Algebras

In suitable states, the modular group of local algebras associated with unions of disjoint intervals in chiral conformal quantum field theory acts geometrically. We translate this result into the setting of boundary conformal QFT and interpret it as a relation between temperature and acceleration. We also discuss novel aspects ("mixing" and "charge splitting") of geometric modular action for unions of disjoint intervals in the vacuum state.

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