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Author Sanchis-Lozano, M.A.
Title Stringy Signals from Large-Angle Correlations in the Cosmic Microwave Background? Type Journal Article
Year 2022 Publication Universe Abbreviated Journal Universe
Volume 8 Issue 8 Pages 396 - 13pp
Keywords cosmic microwave background; angular correlations; inflation; string theory
Abstract We interpret the lack of large-angle temperature correlations and the even-odd parity imbalance observed in the cosmic microwave background (CMB) by COBE, WMAP and Planck satellite missions as a possible stringy signal ultimately stemming from a composite inflaton field (e.g., a fermionic condensate). Based on causality arguments and a Fourier analysis of the angular two-point correlation function, two infrared cutoffs k(min)(even,odd) (satisfying k(min)(even) similar or equal to 2k(min)(odd)) are introduced to the CMB power spectrum associated, respectively, with periodic and antiperiodic boundary conditions of the fermionic constituents (echoing the Neveu-Schwarz-Ramond model in superstring theory), without resorting to any particular model.
Address [Sanchis-Lozano, Miguel-Angel] Univ Valencia, Dept Theoret Phys, Doctor Moliner 50, Burjassot 46011, Spain, Email: miguel.angel.sanchis@ific.uv.es
Corporate Author Thesis
Publisher Mdpi Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) ISBN Medium
Area Expedition Conference
Notes WOS:000845107300001 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 5344
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Author Sanchis-Lozano, M.A.; Melia, F.; Lopez-Corredoira, M.; Sanchis-Gual, N.
Title Missing large-angle correlations versus even-odd point-parity imbalance in the cosmic microwave background Type Journal Article
Year 2022 Publication Astronomy & Astrophysics Abbreviated Journal Astron. Astrophys.
Volume 660 Issue Pages A121 - 10pp
Keywords cosmological parameters; cosmic background radiation; cosmology: observations; cosmology: theory; inflation; large-scale structure of Universe
Abstract Context. The existence of a maximum correlation angle (theta(max) & 60 greater than or similar to degrees) in the two-point angular temperature correlations of cosmic microwave background (CMB) radiation, measured by WMAP and Planck, stands in sharp contrast to the prediction of standard inflationary cosmology, in which the correlations should extend across the full sky (i.e., 180 degrees). The introduction of a hard lower cuto ff (k(min)) in the primordial power spectrum, however, leads naturally to the existence of theta(max). Among other cosmological anomalies detected in these data, an apparent dominance of odd-over-even parity multipoles has been seen in the angular power spectrum of the CMB. This feature, however, may simply be due to observational contamination in certain regions of the sky. Aims. In attempting to provide a more detailed assessment of whether this odd-over-even asymmetry is intrinsic to the CMB, we therefore proceed in this paper, first, to examine whether this odd-even parity imbalance also manifests itself in the angular correlation function and, second, to examine in detail the interplay between the presence of theta(max) and this observed anomaly. Methods. We employed several parity statistics and recalculated the angular correlation function for di fferent values of the cuto ff kmin in order to optimize the fit to the di fferent Planck 2018 data. Results. We find a phenomenological connection between these features in the data, concluding that both must be considered together in order to optimize the theoretical fit to the Planck 2018 data. Conclusions. This outcome is independent of whether the parity imbalance is intrinsic to the CMB, but if it is, the odd-over-even asymmetry would clearly point to the emergence of new physics.
Address [Sanchis-Lozano, M-A] Ctr Mixto Univ Valencia, Inst Fis Corpuscular IFIC, CSIC, Dr Moliner 50, Burjassot, Spain, Email: Miguel.Angel.Sanchis@ific.uv.es;
Corporate Author Thesis
Publisher Edp Sciences S A Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0004-6361 ISBN Medium
Area Expedition Conference
Notes WOS:000786712000002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5211
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Author Giare, W.; Renzi, F.; Mena, O.; Di Valentino, E.; Melchiorri, A.
Title Is the Harrison-Zel'dovich spectrum coming back? ACT preference for n(s) similar to 1 and its discordance with Planck Type Journal Article
Year 2023 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal Mon. Not. Roy. Astron. Soc.
Volume 521 Issue 2 Pages 2911-2918
Keywords cosmological parameters; inflation; cosmology: observations; cosmology: theory
Abstract The Data Release 4 of the Atacama Cosmology Telescope (ACT) shows an agreement with an Harrison-Zel'dovich primordial spectrum (n(s) = 1.009 +/- 0.015), introducing a tension with a significance of 99.3 per cent Confidence Level (CL) with the results from the Planck satellite. The discrepancy on the value of the scalar spectral index is neither alleviated with the addition of large scale structure information nor with the low multipole polarization data. We discuss possible avenues to alleviate the tension relying on either neglecting polarization measurements from ACT or in extending different sectors of the theory.
Address [Giare, William] Ctr Nazl INFN Studi Avanzati, Galileo Galileo Inst Theoret Phys, Largo Enr Fermi 2, I-50125 Florence, Italy, Email: william.giare@gmail.com
Corporate Author Thesis
Publisher Oxford Univ Press Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0035-8711 ISBN Medium
Area Expedition Conference
Notes WOS:000957248500013 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5510
Permanent link to this record
 
 
Author Valle, J.W.F.
Title Status and implications of neutrino masses: a brief panorama Type Journal Article
Year 2015 Publication International Journal of Modern Physics A Abbreviated Journal Int. J. Mod. Phys. A
Volume 30 Issue 13 Pages 1530034 - 13pp
Keywords Neutrino mixing and oscillations; seesaw mechanism; quark-lepton unification; flavor symmetry; electroweak symmetry breaking; neutrinoless double beta decay; dark matter; inflation
Abstract With the historic discovery of the Higgs boson our picutre of particle physics would have been complete were it nor for the neutrino sector and cosmology. I briefly discuss the role of neutrino masses and mixing upon gauge coupling unification, electroweak breaking and the flavor sector. Time is ripe for new discoveries such as leptonic CP violation, charged lepton flavor violation and neutrinoless double beta decay. Neutrinos could also play a role is elucidating the nature of dark matter and cosmic inflation.
Address Univ Valencia, CSIC, Inst Fis Corpuscular, E-46980 Valencia, Spain
Corporate Author Thesis
Publisher World Scientific Publ Co Pte Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0217-751x ISBN Medium
Area Expedition Conference
Notes WOS:000353955400002 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 2211
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Author Agullo, I.; Navarro-Salas, J.; Parker, L.
Title Enhanced local-type inflationary trispectrum from a non-vacuum initial state Type Journal Article
Year 2012 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 05 Issue 5 Pages 019 - 13pp
Keywords inflation; non-gaussianity; quantum field theory on curved space; cosmological perturbation theory
Abstract We compute the primordial trispectrum for curvature perturbations produced during cosmic inflation in models with standard kinetic terms, when the initial quantum state is not necessarily the vacuum state. The presence of initial perturbations enhances the trispectrum amplitude for configuration in which one of the momenta, say k(3), is much smaller than the others, k(3) << k(1,2,4). For those squeezed con figurations the trispectrum acquires the so-called local form, with a scale dependent amplitude that can get values of order epsilon(k(1)/k(3))(2). This amplitude could be larger than the prediction of the so-called Maldacena consistency relation by a factor as large as 10(6), and could reach the sensitivity of forthcoming observations, even for single-field inflationary models.
Address [Agullo, Ivan] Penn State Univ, Inst Gravitat & Cosmos, University Pk, PA 16802 USA, Email: agullo@gravity.psu.edu;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000305415200020 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1083
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Author Norena, J.; Verde, L.; Barenboim, G.; Bosch, C.
Title Prospects for constraining the shape of non-Gaussianity with the scale-dependent bias Type Journal Article
Year 2012 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 08 Issue 8 Pages 019 - 16pp
Keywords redshift surveys; cosmological parameters from LSS; inflation
Abstract We consider whether the non-Gaussian scale-dependent halo bias can be used not only to constrain the local form of non-Gaussianity but also to distinguish among different shapes. In particular, we ask whether it can constrain the behavior of the primordial three-point function in the squeezed limit where one of the momenta is much smaller than the other two. This is potentially interesting since the observation of a three-point function with a squeezed limit that does not go like the local nor equilateral templates would be a signal of non-trivial dynamics during inflation. To this end we use the quasi-single field inflation model of Chen & Wang [1, 2] as a representative two-parameter model, where one parameter governs the amplitude of non-Gaussianity and the other the shape. We also perform a model-independent analysis by parametrizing the scale-dependent bias as a power-law on large scales, where the power is to be constrained from observations. We find that proposed large-scale structure surveys (with characteristics similar to the dark energy task force stage IV surveys) have the potential to distinguish among the squeezed limit behavior of different bispectrum shapes for a wide range of fiducial model parameters. Thus the halo bias can help discriminate between different models of inflation.
Address [Norena, Jorge; Verde, Licia] Univ Barcelona ICC UB IEEC, Inst Ciencias Cosmos, Barcelona 08028, Spain, Email: jorge.norena@icc.ub.edu;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000308800700020 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 1189
Permanent link to this record
 
 
Author Creminelli, P.; Norena, J.; Pena, M.; Simonovic, M.
Title Khronon inflation Type Journal Article
Year 2012 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 11 Issue 11 Pages 032 - 16pp
Keywords inflation; modified gravity; non-gaussianity
Abstract We study the possibility that the approximate time shift symmetry during inflation is promoted to the full invariance under time reparametrization t -> (t) over tilde (t), or equivalently under field redefinition of the inflaton phi -> (phi) over tilde(phi). The symmetry allows only two operators at leading order in derivatives, so that all n-point functions of scalar perturbations are fixed in terms of the power spectrum normalization and the speed of sound. During inflation the decaying mode only decays as 1/a and this opens up the possibility to violate some of the consistency relations in the squeezed limit, although this violation is suppressed by the (small) breaking of the field reparametrization symmetry. In particular one can get terms in the 3-point function that are only suppressed by 1/k(L) in the squeezed limit k(L) -> 0 compared to the local shape.
Address [Creminelli, Paolo] Abdus Salam Int Ctr Theoret Phys, I-34151 Trieste, Italy, Email: creminel@ictp.it;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000312263500015 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1274
Permanent link to this record
 
 
Author Easther, R.; Price, L.C.; Rasero, J.
Title Inflating an inhomogeneous universe Type Journal Article
Year 2014 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 08 Issue 8 Pages 041 - 16pp
Keywords inflation; initial conditions and eternal universe; physics of the early universe
Abstract While cosmological inflation can erase primordial inhomogeneities, it is possible that inflation may not begin in a significantly inhomogeneous universe. This issue is particularly pressing in multifield scenarios, where even the homogeneous dynamics may depend sensitively on the initial configuration. This paper presents an initial survey of the onset of inflation in multifield models, via qualitative lattice-based simulations that do not include local gravitational backreaction. Using hybrid inflation as a test model, our results suggest that small subhorizon inhomogeneities do play a key role in determining whether inflation begins in multifield scenarios. Interestingly, some configurations which do not inflate in the homogeneous limit “succeed” after inhomogeneity is included, while other initial configurations which inflate in the homogeneous limit “fail” when inhomogeneity is added.
Address [Easther, Richard; Price, Layne C.] Univ Auckland, Dept Phys, Auckland, New Zealand, Email: r.easther@auckland.ac.nz;
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000341848800041 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1943
Permanent link to this record
 
 
Author Pallis, C.
Title Induced-gravity in inflation no-scale supergravity and beyond Type Journal Article
Year 2014 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 08 Issue 8 Pages 057 - 20pp
Keywords inflation; supersymmetry and cosmology
Abstract Supersymmetric versions of induced-gravity inflation are formulated within Supergravity (SUGRA) employing two gauge singlet chiral super fields. The proposed super-potential is uniquely determined by applying a continuous R and a discrete Z(n) symmetry. We select two types of logarithmic Kahler potentials, one associated with a no-scale-type SU(2, 1)/SU(2) x U(1)(R) x Z(n) Kahler manifold and one more generic. In both cases, imposing a lower bound on the parameter c R involved in the coupling between the inflaton and the Ricci scalar curvature – e.g. c(R) greater than or similar to 76, 105, 310 for n – 2, 3 and 6 respectively -, inflation can be attained even for subplanckian values of the inflaton while the corresponding effective theory respects the perturbative unitarity. In the case of no-scale SUGRA we show that, for every n, the inflationary observables remain unchanged and in agreement with the current data while the inflaton mass is predicted to be 3 . 10(13) GeV. Beyond no-scale SUGRA the inflationary observables depend mildly on n and crucially on the coefficient involved in the fourth order term of the Kahler potential which mixes the inflaton with the accompanying non-inflaton field.
Address [Pallis, C.] Univ Valencia, CSIC, Dept Fis Teor, E-46100 Burjassot, Spain, Email: kpallis@gen.auth.gr
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000341848800057 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 1944
Permanent link to this record
 
 
Author Pallis, C.
Title Linking Starobinsky-type inflation in no-scale supergravity to MSSM Type Journal Article
Year 2014 Publication Journal of Cosmology and Astroparticle Physics Abbreviated Journal J. Cosmol. Astropart. Phys.
Volume 04 Issue 4 Pages 024 - 31pp
Keywords particle physics – cosmology connection; supersymmetry and cosmology; cosmology of theories beyond the SM; inflation
Abstract A novel realization of the Starobinsky inflationary model within a moderate extension of the Minimal Supersymmetric Standard Model (MSSM) is presented. The proposed superpotential is uniquely determined by applying a continuous R and a Z2 discrete symmetry, whereas the Kahler potential is associated with a no-scale-type SU(54, 1)/ SU(54) x U(1) R X Z2 Kahler manifold. The inflaton is identified with a Higgs-like modulus whose the vacuum expectation value controls the gravitational strength. Thanks to a strong enough coupling (with a parameter CT involved) between the inflaton and the Ricci scalar curvature, inflation can be attained even for subplanckian values of the inflaton with CT >= 76 and the corresponding effective theory being valid up to the Planck scale. The inflationary observables turn out to be in agreement with the current data and the inflaton mass is predicted to be 3 10(3) GeV. At the cost of a relatively small superpotential coupling constant, the model offers also a resolution of the f,t problem of MSSM for CT <= 4500 and gravitino heavier than about 10(4) GeV. Supplementing MSSM by three right-handed neutrinos we show that spontaneously arising couplings between the inflaton and the particle content of MSSM not only ensure a sufficiently low reheating temperature but also support a scenario of non-thermal leptogenesis consistently with the neutrino oscillation parameters.
Address [Pallis, C.] Univ Valencia, CSIC, Dept Fis Teor, E-46100 Burjassot, Spain, Email: kpallis@auth.gr
Corporate Author Thesis
Publisher Iop Publishing Ltd Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 1475-7516 ISBN Medium
Area Expedition Conference
Notes WOS:000343042800006 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 1961
Permanent link to this record