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Author (up) del Rio, A.; Navarro-Salas, J.
Title Spacetime correlators of perturbations in slow-roll de Sitter inflation Type Journal Article
Year 2014 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 89 Issue 8 Pages 084037 - 7pp
Keywords
Abstract Two-point correlators and self-correlators of primordial perturbations in quasi-de Sitter spacetime backgrounds are considered. For large separations two-point correlators exhibit nearly scale invariance, while for short distances self-correlators need standard renormalization. We study the deformation of two-point correlators to smoothly match the self-correlators at coincidence. The corresponding angular power spectrum is evaluated in the Sachs-Wolfe regime of low multipoles. Scale invariance is maintained, but the amplitude of C(l)could change in a nontrivial way.
Address [del Rio, Adrian] Univ Valencia, Fac Fis, Ctr Mixto Univ Valencia CSIC, Dept Fis Teor, E-46100 Valencia, Spain
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1550-7998 ISBN Medium
Area Expedition Conference
Notes WOS:000334335200008 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 1768
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Author (up) del Rio, A.; Navarro-Salas, J.; Torrenti, F.
Title Renormalized stress-energy tensor for spin-1/2 fields in expanding universes Type Journal Article
Year 2014 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 90 Issue 8 Pages 084017 - 15pp
Keywords
Abstract We provide an explicit expression for the renormalized expectation value of the stress-energy tensor of a spin-1/2 field in a spatially flat Friedmann-Lemaitre-Robertson-Walker universe. Its computation is based on the extension of the adiabatic regularization method to fermion fields introduced recently in the literature. The tensor is given in terms of UV-finite integrals in momentum space, which involve the mode functions that define the quantum state. As illustrative examples of the method efficiency, we see how to compute the renormalized energy density and pressure in two interesting cosmological scenarios: a de Sitter spacetime and a radiation-dominated universe. In the second case, we explicitly show that the late-time renormalized stress-energy tensor behaves as that of classical cold matter. We also check that, if we obtain the adiabatic expansion of the scalar field mode functions with a similar procedure to the one used for fermions, we recover the well-known WKB-type expansion.
Address [del Rio, Adrian; Navarro-Salas, Jose] Univ Valencia, Dept Fis Teor, E-46100 Burjassot, Valencia, Spain, Email: adrian.rio@uv.es;
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1550-7998 ISBN Medium
Area Expedition Conference
Notes WOS:000343773100003 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 1985
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Author (up) del Rio, A.; Sanchis-Gual, N.; Mewes, V.; Agullo, I.; Font, J.A.; Navarro-Salas, J.
Title Spontaneous Creation of Circularly Polarized Photons in Chiral Astrophysical Systems Type Journal Article
Year 2020 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 124 Issue 21 Pages 211301 - 6pp
Keywords
Abstract This work establishes a relation between chiral anomalies in curved spacetimes and the radiative content of the gravitational field. In particular, we show that a flux of circularly polarized gravitational waves triggers the spontaneous creation of photons with net circular polarization from the quantum vacuum. Using waveform catalogs, we identify precessing binary black holes as astrophysical configurations that emit such gravitational radiation and then solve the fully nonlinear Einstein's equations with numerical relativity to evaluate the net effect. The quantum amplitude for a merger is comparable to the Hawking emission rate of the final black hole and small to be directly observed. However, the implications for the inspiral of binary neutron stars could be more prominent, as argued on symmetry grounds.
Address [del Rio, Adrian; Sanchis-Gual, Nicolas] Univ Lisbon, Inst Super Tecn, Ctr Astrofis & Gravitacao CENTRA, Ave Rovisco Pais 1, P-1049001 Lisbon, Portugal
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007 ISBN Medium
Area Expedition Conference
Notes WOS:000535679100012 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4407
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Author (up) Sanchis-Gual, N.; del Rio, A.
Title Precessing binary black holes as engines of electromagnetic helicity Type Journal Article
Year 2023 Publication Physical Review D Abbreviated Journal Phys. Rev. D
Volume 108 Issue Pages 044052 - 11pp
Keywords
Abstract We show that binary black hole mergers with precessing evolution can potentially excite photons from the quantum vacuum in such a way that total helicity is not preserved in the process. Helicity violation is allowed by quantum fluctuations that spoil the electric-magnetic duality symmetry of the classical Maxwell theory without charges. We show here that precessing binary black hole systems in astrophysics generate a flux of circularly polarized gravitational waves which, in turn, provides the required helical background that triggers this quantum effect. Solving the fully nonlinear Einstein’s equations with numerical relativity we explore the parameter space of binary systems and extract the detailed dependence of the quantum effect with the spins of the two black holes. We also introduce a set of diagrammatic techniques that allows us to predict when a binary black hole merger can or cannot emit circularly polarized gravitational radiation, based on mirror-symmetry considerations. This framework allows to understand and to interpret correctly the numerical results, and to predict the outcomes in potentially interesting astrophysical systems.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 6092
Permanent link to this record