Singular Functions in Quantum Field Theory with De Sitter Momentum Space

1997 ◽  
Vol 12 (01) ◽  
pp. 255-258
Author(s):  
R. M. Mir-Kasimov
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Scalar Field ◽  
Explicit Form ◽  
Momentum Space ◽  
Legendre Functions ◽  
Quantum Field ◽  
De Sitter ◽  
Singular Functions ◽  
Positive Frequency

The positive frequency part of commutation Pauli-Jordan function in the Quantum Field Theory with curved momentum space or Quantum configurational space is calculated in explicit form for scalar field. The expressions for other siigular functions are also written in terms of Legendre functions

scholarly journals Revisiting Coleman-de Luccia transitions in the AdS regime using holography

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Jewel K. Ghosh ◽  
Elias Kiritsis ◽  
Francesco Nitti ◽  
Lukas T. Witkowski
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Scalar Field ◽  
Flat Space ◽  
Field Theories ◽  
Quantum Field ◽  
De Sitter ◽  
Thin Walled ◽  
Scalar Theories ◽  
Scalar Potentials

Abstract Coleman-de Luccia processes for AdS to AdS decays in Einstein-scalar theories are studied. Such tunnelling processes are interpreted as vev-driven holographic RG flows of a quantum field theory on de Sitter space-time. These flows do not exist for generic scalar potentials, which is the holographic formulation of the fact that gravity can act to stabilise false AdS vacua. The existence of Coleman-de Luccia tunnelling solutions in a potential with a false AdS vacuum is found to be tied to the existence of exotic RG flows in the same potential. Such flows are solutions where the flow skips possible fixed points or reverses direction in the coupling. This connection is employed to construct explicit potentials that admit Coleman-de Luccia instantons in AdS and to study the associated tunnelling solutions. Thin-walled instantons are observed to correspond to dual field theories with a parametrically large value of the dimension ∆ for the operator dual to the scalar field, casting doubt on the attainability of this regime in holography. From the boundary perspective, maximally symmetric instantons describe the probability of symmetry breaking of the dual QFT in de Sitter. It is argued that, even when such instantons exist, they do not imply an instability of the same theory on flat space or on R × S3.

Quantum field theory in de Sitter space: renormalization by point-splitting

1978 ◽  
Vol 360 (1700) ◽  
pp. 117-134 ◽  
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Scalar Field ◽  
Stress Tensor ◽  
Dimensional Regularization ◽  
De Sitter Space ◽  
Quantum Field ◽  
De Sitter ◽  
Point Splitting

We examine the modes of a scalar field in de Sitter space and construct quantum two-point functions. These are then used to compute a finite stress tensor by the technique of covariant point-splitting. We propose a renormalization ansatz based on the DeWitt-Schwinger expansion, and show that this removes all am biguities previously present in pointsplitting regularization. The results agree in detail with previous work by dimensional regularization, and give rise to an anomalous trace with the conventional coefficient. We describe how’ our treatment may be extended to more general situations.

scholarly journals The Dirac Sea, T and C Symmetry Breaking, and the Spinor Vacuum of the Universe

Universe ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 124
Author(s):  
Vadim Monakhov
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Symmetry Breaking ◽  
Momentum Space ◽  
Quantum Field ◽  
Conjugation Operator ◽  
Dirac Sea ◽  
Canonical Anticommutation Relations ◽  
The Universe ◽  
Dirac Conjugation

We have developed a quantum field theory of spinors based on the algebra of canonical anticommutation relations (CAR algebra) of Grassmann densities in the momentum space. We have proven the existence of two spinor vacua. Operators C and T transform the normal vacuum into an alternative one, which leads to the breaking of the C and T symmetries. The CPT is the real structure operator; it preserves the normal vacuum. We have proven that, in the theory of the Dirac Sea, the formula for the charge conjugation operator must contain an additional generalized Dirac conjugation operator.

Quantum field theory in anti-de Sitter space-time

1978 ◽  
Vol 18 (10) ◽  
pp. 3565-3576 ◽  
Author(s):  
S. J. Avis ◽  
C. J. Isham ◽  
D. Storey
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
De Sitter Space ◽  
Space Time ◽  
Quantum Field ◽  
De Sitter

Momentum space techniques for curved space–time quantum field theory

1979 ◽  
Vol 367 (1728) ◽  
pp. 123-141 ◽  
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Momentum Space ◽  
Nuclear Physics ◽  
Space Time ◽  
Coordinate Space ◽  
Quantum Field ◽  
Curved Space ◽  
Time Quantum ◽  
Space Formulation

A momentum space formulation of curved space–time quantum field theory is presented. Such a formulation allows the riches of momentum space calculational techniques already existing in nuclear physics to be exploited in the application of quantum field theory to cosmology and astrophysics. It is demonstrated that one such technique can allow exact, or very accu­rate approximate, results to be obtained in cases which are intractable in coordinate space. An efficient method of numerical solution is also described.

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