scholarly journals Comment on “Hadamard states for a scalar field in anti–de Sitter spacetime with arbitrary boundary conditions”

2019 ◽  
Vol 99 (10) ◽  
Author(s):  
J. P. M. Pitelli
Keyword(s):  
Scalar Field ◽  
Boundary Conditions ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Arbitrary Boundary ◽  
Arbitrary Boundary Conditions ◽  
Sitter Spacetime ◽  
Hadamard States

scholarly journals On the algebraic quantization of a massive scalar field in anti-de Sitter spacetime

2018 ◽  
Vol 30 (02) ◽  
pp. 1850004 ◽  
Author(s):  
Claudio Dappiaggi ◽  
Hugo R. C. Ferreira
Keyword(s):  
Scalar Field ◽  
De Sitter Spacetime ◽  
Massive Scalar ◽  
De Sitter ◽  
Functional Formalism ◽  
Arbitrary Boundary ◽  
Massive Scalar Field ◽  
Sitter Spacetime ◽  
Hadamard States ◽  
Definition Of

We discuss the algebraic quantization of a real, massive scalar field in the Poincaré patch of the [Formula: see text]-dimensional anti-de Sitter spacetime, with arbitrary boundary conditions. By using the functional formalism, we show that it is always possible to associate to such system an algebra of observables enjoying the standard properties of causality, time-slice axiom and F-locality. In addition, we characterize the wavefront set of the ground state associated to the system under investigation. As a consequence, we are able to generalize the definition of Hadamard states and construct a global algebra of Wick polynomials.

scholarly journals Light in dielectric media and scalar fields in a de Sitter spacetime

2021 ◽  
Vol 81 (8) ◽  
Author(s):  
I. A. Pedrosa ◽  
B. F. Ramos ◽  
K. Bakke
Keyword(s):  
Scalar Field ◽  
Coherent States ◽  
Scalar Fields ◽  
Dielectric Medium ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Expectation Values ◽  
Dielectric Media ◽  
Sitter Spacetime ◽  
Constant Rate

AbstractIn the present work we discuss the behavior of light in a linear dielectric medium with a time-varying electric permittivity that increases exponentially at a constant rate and of a scalar field in a de Sitter spacetime, in both the classical and quantum contexts. Notably, we find that the behavior of these two systems are identical and can be described by similar Hamiltonians. By using the Lewis–Riesenfeld invariant method together with Fock states we solve the time-dependent Schrödinger equation for this problem and use its solutions to construct coherent states for the scalar field. Finally, we employ both the Fock and coherent states to evaluate some important properties of the quantized scalar field, such as expectation values of the amplitude and momentum of each mode their variances and the respective uncertainty principle.

scholarly journals AMPLITUDE OF COULOMB SCATTERING FOR CHARGED SCALAR FIELD IN DE SITTER SPACETIME

2010 ◽  
Vol 25 (20) ◽  
pp. 1679-1687 ◽  
Author(s):  
COSMIN CRUCEAN
Keyword(s):  
Scalar Field ◽  
Gordon Equation ◽  
Coulomb Scattering ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Scattering Process ◽  
Charged Scalar ◽  
Sitter Spacetime ◽  
Klein Gordon ◽  
Charged Scalar Field

The scattering of a charged scalar field on Coulomb potential is studied using solutions of the Klein–Gordon equation which have a definite momentum. One obtains that the modulus of momentum is not conserved in the scattering process on de Sitter space.

scholarly journals Unruh-DeWitt detector responses for complex scalar fields in de Sitter spacetime

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Md Sabir Ali ◽  
Sourav Bhattacharya ◽  
Kinjalk Lochan
Keyword(s):  
Scalar Field ◽  
Response Function ◽  
Scalar Fields ◽  
Detector Response ◽  
Massless Scalar Field ◽  
De Sitter Spacetime ◽  
De Sitter ◽  
Complex Scalar ◽  
Sitter Spacetime ◽  
Complex Scalar Field

Abstract We derive the response function for a comoving, pointlike Unruh-DeWitt particle detector coupled to a complex scalar field ϕ, in the (3 + 1)-dimensional cosmological de Sitter spacetime. The field-detector coupling is taken to be proportional to ϕ†ϕ. We address both conformally invariant and massless minimally coupled scalar field theories, respectively in the conformal and the Bunch-Davies vacuum. The response function integral for the massless minimal complex scalar, not surprisingly, shows divergences and accordingly we use suitable regularisation scheme to find out well behaved results. The regularised result also contains a de Sitter symmetry breaking logarithm, growing with the cosmological time. Possibility of extension of these results with the so called de Sitter α-vacua is discussed. While we find no apparent problem in computing the response function for a real scalar in these vacua, a complex scalar field is shown to contain some possible ambiguities in the detector response. The case of the minimal and nearly massless scalar field theory is also briefly discussed.

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