15 citations · 160 across the 29 of their papers we have counts for
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A unified framework for graviton, "partially massless" graviton, and photon fields in de Sitter spacetime under conformal symmetry
Jean-Pierre Gazeau, Hamed Pejhan
We develop a conformally invariant (CI) framework in -dimensional de Sitter (dS) spacetime, that unifies the descriptions of graviton, ``partially massless'' graviton, and p…
Matter-antimatter (a)symmetry in de Sitter Universe
Jean-Pierre Gazeau, Hamed Pejhan
We investigate the matter-antimatter properties of elementary systems, modeled as free quantum fields, within the global structure of de Sitter spacetime. By leveraging the distinc…
A misleading naming convention: de Sitter `tachyonic' scalar fields
Jean-Pierre Gazeau, Hamed Pejhan
We revisit the concept of de Sitter (dS) 'tachyonic' scalar fields, characterized by discrete negative squared mass values, and assess their physical significance through a rigorou…
Covariant Quantization of the Partially Massless Graviton Field in de Sitter Spacetime
Jean-Pierre Gazeau, Hamed Pejhan
We present a covariant quantization scheme for the so-called "partially massless" graviton field in de Sitter spacetime. Our approach is founded on the principles of the de Sitter…
"Massive" Rarita-Schwinger field in de Sitter space
Hamed Pejhan, Mohammad Enayati, Jean-Pierre Gazeau +1
We present a covariant quantization of the "massive" spin- Rarita-Schwinger field in de Sitter (dS) spacetime. The dS group representation theory and its Wigner inte…
Gupta-Bleuler quantization for linearized gravity in de Sitter spacetime
Hamed Pejhan, Mohammad Enayati, Jean-Pierre Gazeau +1
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 e…
`Hidden' symmetry of linearized gravity in de Sitter space
Hamed Pejhan, Surena Rahbardehghan, Mohammad Enayati +2
We demonstrate that the linearized Einstein gravity in de Sitter (dS) spacetime besides the evident symmetries also possesses the additional (local) symmetry $h_{μν}\rightarrow h_{…
A small non-vanishing cosmological constant from the Krein-Gupta-Bleuler vacuum
Hamed Pejhan, Kazuharu Bamba, Mohammad Enayati +1
We point out a potential relevance between the Krein-Gupta-Bleuler (KGB) vacuum leading to a fully covariant quantum field theory for gravity in de Sitter (dS) spacetime and the ob…
"Massless" spin-2 field in de Sitter space
Hamed Pejhan, Kazuharu Bamba, Surena Rahbardehghan +1
In this paper, admitting a de Sitter (dS)-invariant vacuum in an indefinite inner product space, we present a Gupta-Bleuler type setting for causal and full dS-covariant quantizati…
Vacuum states for gravitons field in de Sitter space
Kazuharu Bamba, Surena Rahbardehghan, Hamed Pejhan
In this paper, considering the linearized Einstein equation with a two-parameter family of linear covariant gauges in de Sitter spacetime, we examine possible vacuum states for the…
On the graviton two-point function and its infrared behavior in de Sitter spacetime
Surena Rahbardehghan, Hamed Pejhan
In our previous paper (Phys. Rev. D 94, 104030 (2016)), inspired by the work of Allen and Turyn (Nucl. Phys. B 292, 813 (1987)), we expressed the graviton two-point function in ter…
Covariant and infrared-free graviton two-point function in de Sitter spacetime II
Hamed Pejhan, Surena Rahbardehghan
The solution to the linearized Einstein equation in de Sitter (dS) spacetime and the corresponding two-point function are explicitly written down in a gauge with two parameters `$a…
Casimir energy-momentum tensor for a quantized bulk scalar field in the geometry of two curved branes on Friedmann-Robertson-Walker background
Hamed Pejhan, Surena Rahbardehghan
In a previous work [S. Rahbardehghan et al. in Phys. Lett. B 750, 627 (2015)], we considered a simple brane-world model; a single -dimensional brane embedded in a -dimensiona…
Covariant and infrared-free graviton two-point function in de Sitter spacetime
Hamed Pejhan, Surena Rahbardehghan
In this paper, the two-point function of linearized gravitons on de Sitter (dS) space is presented. Technically, respecting the dS ambient space notation, the field equation is giv…
Examining a covariant and renormalizable quantum field theory in de Sitter space by studying "black hole radiation"
Hamed Pejhan, Surena Rahbardehghan
Respecting that any consistent quantum field theory in curved space-time must include black hole radiation, in this paper, we examine the Krein-Gupta-Bleuler (KGB) formalism as an…
The Krein-Gupta-Bleuler Quantization in de Sitter Space-time; Casimir Energy-Momentum Tensor for a Curved Brane
S. Rahbardehghan, H. Pejhan
In this paper, vacuum expectation value (VEV) of the energy-momentum tensor for a conformally coupled scalar field in de Sitter space-time is investigated through the Krein-Gupta-B…
A Group Theoretical Approach to Graviton Two-Point Function
S. Rahbardehghan, H. Pejhan, M. Elmizadeh
Respecting the group theoretical approach, it is debated that the theory of linear conformal gravity should be formulated through a tensor field of rank-3 and mixed symmetry \cite{…
Conformal linear gravity in de Sitter space II
M. V. Takook, H. Pejhan, M. Reza Tanhayi
From the group theoretical point of view, it is proved that the theory of linear conformal gravity should be written in terms of a tensor field of rank-3 and mixed symmetry [Binega…
Auxiliary "massless" spin-2 field in de Sitter universe
H. Pejhan, M. R. Tanhayi, M. V. Takook
For the tensor field of rank-2 there are two unitary irreducible representation (UIR) in de Sitter (dS) space denoted by and [1]. In the flat limit…