scholarly journals Strict deformations of quantum field theory in de Sitter spacetime

2021 ◽  
Vol 62 (6) ◽  
pp. 062302
Author(s):  
M. B. Fröb ◽  
A. Much
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
De Sitter Spacetime ◽  
Quantum Field ◽  
De Sitter ◽  
Sitter Spacetime

scholarly journals Finite lifespan of solutions of the semilinear wave equation in the Einstein–de Sitter spacetime

2019 ◽  
Vol 32 (07) ◽  
pp. 2050018 ◽  
Author(s):  
Anahit Galstian ◽  
Karen Yagdjian
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Wave Equation ◽  
De Sitter Spacetime ◽  
Quantum Field ◽  
De Sitter ◽  
Semilinear Wave Equation ◽  
Sitter Spacetime ◽  
Text Model ◽  
De Sitter Universe

We examine the solutions of the semilinear wave equation, and, in particular, of the [Formula: see text] model of quantum field theory in the curved spacetime. More exactly, for [Formula: see text] we prove that the solution of the massless self-interacting scalar field equation in the Einstein–de Sitter universe has finite lifespan.

scholarly journals Topological surprises in de Sitter QFT in two-dimensions

2018 ◽  
Vol 33 (34) ◽  
pp. 1845009 ◽  
Author(s):  
Henri Epstein ◽  
Ugo Moschella
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Thermal State ◽  
Two Dimensions ◽  
Quantum Field ◽  
De Sitter ◽  
Sitter Spacetime ◽  
Klein Gordon ◽  
New Type ◽  
Two Universes

Motivated by the study of soluble models of quantum field theory, we illustrate a new type of topological effect by comparing the constructions of canonical Klein–Gordon quantum fields on the two-dimensional de Sitter spacetime as opposed to its double covering. We show that while the commutators of the two fields coincide locally, the global topological differences make the theories drastically different. Many of the well-known features of de Sitter quantum field theory disappear. In particular, there is nothing like a Bunch–Davies vacuum. Correspondingly, even though the local horizon structure is the same for the two universes, there is no Hawking–Gibbons thermal state. Finally, there is no complementary series of fields.

scholarly journals Classical Simulations of Quantum Field Theory in Curved Spacetime I: Fermionic Hawking-Hartle Vacua from a Staggered Lattice Scheme

Quantum ◽  
2020 ◽  
Vol 4 ◽  
pp. 351
Author(s):  
Adam G. M. Lewis ◽  
Guifré Vidal
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Unruh Effect ◽  
Dirac Fermions ◽  
Quantum Field ◽  
De Sitter ◽  
Curved Spacetime ◽  
Expectation Values ◽  
Sitter Spacetime ◽  
The Continuum

We numerically compute renormalized expectation values of quadratic operators in a quantum field theory (QFT) of free Dirac fermions in curved two-dimensional (Lorentzian) spacetime. First, we use a staggered-fermion discretization to generate a sequence of lattice theories yielding the desired QFT in the continuum limit. Numerically-computed lattice correlators are then used to approximate, through extrapolation, those in the continuum. Finally, we use so-called point-splitting regularization and Hadamard renormalization to remove divergences, and thus obtain finite, renormalized expectation values of quadratic operators in the continuum. As illustrative applications, we show how to recover the Unruh effect in flat spacetime and how to compute renormalized expectation values in the Hawking-Hartle vacuum of a Schwarzschild black hole and in the Bunch-Davies vacuum of an expanding universe described by de Sitter spacetime. Although here we address a non-interacting QFT using free fermion techniques, the framework described in this paper lays the groundwork for a series of subsequent studies involving simulation of interacting QFTs in curved spacetime by tensor network techniques.

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
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