A small non-vanishing cosmological constant from the Krein–Gupta–Bleuler vacuum

Pejhan, Hamed; Bamba, Kazuharu; Enayati, Mohammad; Rahbardehghan, Surena

doi:10.1016/j.physletb.2018.09.017

Cited by 8 publications

(8 citation statements)

References 26 publications

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“…In the KGB context, despite the presence of negative norm sates in the theory, the energy operator is positive in all physical states, and vanishes in the vacuum. Recently, a preliminary estimate of the expected order of magnitude of vacuum energy density stored in the cosmological constant today with respect to the KGB vacuum, presented in [39], has been shown that the obtained result demonstrates a remarkable coincidence with the observational data. This coincidence seems to be almost too good to be just an accident.…”

Section: Discussionsupporting

confidence: 54%

‘Hidden’ symmetry of linearized gravity in de Sitter space

et al. 2019

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We demonstrate that the linearized Einstein gravity in de Sitter (dS) spacetime besides the evident symmetries also possesses the additional (local) symmetry hµν → hµν + Eµν χ, where Eµν is a spintwo projector tensor and χ is an arbitrary constant function. We argue that an anomalous symmetry associated with this hitherto 'hidden' property of the existing physics is indeed at the origin of 'dS breaking' in linearized quantum gravity.

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Section: Discussionsupporting

confidence: 54%

‘Hidden’ symmetry of linearized gravity in de Sitter space

et al. 2019

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“…• In the semiclassical description of general relativity (Λ > 0) when matter field is present, a preliminary estimate of the expected order of magnitude of vacuum energy density stored in the cosmological constant today with respect to the KGB vacuum yields a remarkable coincidence with the empirical data [57].…”

Section: Discussionmentioning

confidence: 73%

“…As a direct consequence, the vacuum energy of the free field in this construction automatically vanishes, Ω|T 00 |Ω = 0. This property has an interesting link to the cosmological constant problem (see [57]).…”

Section: B Quantum Observablesmentioning

confidence: 99%

Gupta-Bleuler quantization for linearized gravity in de Sitter spacetime

et al. 2019

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In a recent Letter, we have pointed out that the linearized Einstein gravity in de Sitter (dS) spacetime besides the spacetime symmetries generated by the Killing vectors and the evident gauge symmetry also possesses a hitherto 'hidden' local (gauge-like) symmetry which becomes anomalous on the quantum level. This gauge-like anomaly makes the theory inconsistent and must be canceled at all costs. In this companion paper, we first review our argument and discuss it in more detail. We argue that the cancelation of this anomaly makes it impossible to preserve dS symmetry in linearized quantum gravity through the usual canonical quantization in a consistent manner. Then, demanding that all the classical symmetries to survive in the quantized theory, we set up a coordinate-independent formalismà la Gupta-Bleuler which allows for preserving the (manifest) dS covariance in the presence of the gauge and the gauge-like invariance of the theory. On this basis, considering a new representation of the canonical commutation relations, we present a graviton quantum field on dS space, transforming correctly under isometries, gauge transformations, and gauge-like transformations, which acts on a state space containing a vacuum invariant under all of them. Despite the appearance of negative norm states in this quantization scheme, the energy operator is positive in all physical states, and vanishes in the vacuum. * pejhan@zjut.edu.cn † gazeau@apc.in2p3.fr ‡ Anzhong-Wang@baylor.edu 1 Here, in order to make our discussion explicit, we have used the so-called conformal (global) coordinates,

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“…To see more on this automatic renormalization procedure and its physical consequences, readers are referred to Refs. [123,124].…”

Section: Stress Tensormentioning

confidence: 99%

The de Sitter group and its representations: a window on the notion of de Sitterian elementary systems

Enayati,

Gazeau,

Pejhan

et al. 2022

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We review the construction of ("free") elementary systems in de Sitter (dS) spacetime, in the Wigner sense, as associated with unitary irreducible representations (UIR's) of the dS (relativity) group. This study emphasizes the conceptual issues arising in the formulation of such systems and discusses known results in a mathematically rigorous way. Particular attention is paid to: "smooth" transition from classical to quantum theory; physical content under vanishing curvature, from the point of view of a local ("tangent") Minkowskian observer; and thermal interpretation (on the quantum level), in the sense of the Gibbons-Hawking temperature. We review three decompositions of the dS group physically relevant for the description of dS spacetime and classical phase spaces of elementary systems living on it. We review the construction of (projective) dS UIR's issued from these group decompositions. (Projective) Hilbert spaces carrying the UIR's (in some restricted sense) identify quantum ("one-particle") states spaces of dS elementary systems. Adopting a well-established Fock procedure, based on the Wightman-Gärding axiomatic and on analyticity requirements in the complexified Riemannian manifold, we proceed with a consistent quantum field theory (QFT) formulation of elementary systems in dS spacetime. This dS QFT formulation closely parallels the corresponding Minkowskian one, while the usual spectral condition is replaced by a certain geometric Kubo-Martin-Schwinger (KMS) condition equivalent to a precise thermal manifestation of the associated "vacuum" states. We end our study by reviewing a consistent and univocal definition of mass in dS relativity. This definition, presented in terms of invariant parameters characterizing the dS UIR's, accurately gives sense to terms like "massive" and "massless" fields in dS relativity according to their Minkowskian counterparts, yielded by the group contraction procedures. Contents

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A small non-vanishing cosmological constant from the Krein–Gupta–Bleuler vacuum

Cited by 8 publications

References 26 publications

‘Hidden’ symmetry of linearized gravity in de Sitter space

‘Hidden’ symmetry of linearized gravity in de Sitter space

Gupta-Bleuler quantization for linearized gravity in de Sitter spacetime

The de Sitter group and its representations: a window on the notion of de Sitterian elementary systems

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