David Nolde
(University of Basel)

24/09/2014, 14:00

With the indications for r > 0.1 by BICEP2, there have been discussions about whether all small-field models of inflation could be ruled out due to the Lyth bound, or if the Lyth bound can be evaded by specific choices of the inflaton potential. We show that in single-field slow-roll inflation, it is impossible to reconcile r > 0.1 with field excursions \Delta \phi << M_pl, independently of...

Mr
Marco Scalisi
(University of Groningen)

24/09/2014, 14:20

We investigate the nature of inflationary parameters at large values of the number of e-foldings N. We analyze the behaviour of the inflationary field range in such a limit and provide strong evidence for universality features of it. Finally, we use these results in order to derive a model-independent field range bound as a function even of the spectral index. We show that Planck's measurement...

Dr
Jan Heisig
(RWTH Aachen University)

24/09/2014, 14:40

The measurement of primordial tensor modes in the CMB allows for a determination of the energy scale at the beginning of the `observable' part of inflation. We show in how far such a measurement provides implications for the subsequent phase of inflation and the post-inflationary phase of reheating. Further, we will revise the gravitino problem and show the implications for a supersymmetric...

Dr
Stefano Orani
(Basel University)

24/09/2014, 15:00

We investigate to which extent and under which circumstances false vacuum energy (V0) dominated slow-roll inflation is compatible with a large tensor-to-scalar ratio r=O(0.1), as indicated by the recent BICEP2 measurement. With V0 we refer to a constant contribution to the inflaton potential, present before a phase transition takes place and absent in the true vacuum of the theory, like e.g....

Valerie Domcke
(SISSA/INFN)

24/09/2014, 15:20

In this talk, I discuss how a period of `chaotic inflation' with a sizeable tensor-to-scalar ratio naturally arises from the decay of a false vacuum of GUT-scale energy. We consider D-term inflation for small couplings of the inflaton to matter fields. Standard hybrid inflation then ends at a critical value of the inflaton field that exceeds the Planck mass. During the subsequent waterfall...

Dr
Gabriella Piccinelli
(Universidad Nacional Autónoma de México)

24/09/2014, 16:10

Magnetic fields are ubiquitous in the Universe and their generation mechanism is an open problem in cosmology. Their presence on all scales strengthens the idea of a primordial origin. If this is the case, a magnetic cosmological model has to be built. Here, we discuss the possible effects that primordial magnetic fields can have on a warm inflation scenario, in particular on the inflaton...

Dr
Encieh Erfani
(IPM, Iran)

24/09/2014, 16:25

Primordial Black Holes (PBHs) are gravitationally collapsed objects that may have been created by density fluctuations caused by Inflation in the early universe. A broad range of single field models of inflation are analyzed in light of all relevant recent cosmological data, checking whether they can lead to the formation of longlived PBHs as candidate for dark matter. To that end we calculate...

Dr
Shinta Kasuya
(Kanagawa University)

24/09/2014, 16:40

We investigate the variant of the Affleck-Dine mechanism in high-scale inflation. The scenario utilizes multiple flat directions, which is generally present in the MSSM. One flat direction creates baryon asymmetry of the universe, while Q balls from another direction can be the dark matter in the gauge-mediated supersymmetry breaking. Isocurvature fluctuations are suppressed by the fact that...

Dr
Yuko Urakawa
(Institute for Advanced Research, Nagoya University)

24/09/2014, 17:10

A naive perturbation theory predicts that loop corrections generated during inflation suffer from various infrared (IR) divergences. We discuss the origin of the IR divergences and explore the regularity conditions, which will restrict the possible initial states of inflationary universe. This talk is based on our recent works, summarized in the review article, Class.Quant.Grav. 30 (2013)...

Mr
Sreenath Vijayakumar
(Indian Institute of Technology Madras)

24/09/2014, 17:25

The detection of the imprints of the primordial tensor perturbations by BICEP2 and its indication of a rather high tensor-to-scalar ratio, if confirmed, can open up a new window for understanding the tensor perturbations, not only at the level of the power spectrum, but also in the realm of non-Gaussianities. In this work, we consider the consistency relations associated with the three-point...

Mr
Benedict Broy
(Deutsches Elektron Synchrotron DESY)

25/09/2014, 14:00

Inflationary attractors predict the spectral index and tensor-to-scalar ratio to take specific values that are consistent with Planck. Moreover, in this letter we demonstrate that they also give rise to a specific relation between the amplitude of the power spectrum and the number of e-folds. We investigate this relation in the context of the universal attractor for models with a...

Dr
Sabir Ramazanov
(Universite Libre de Bruxelles)

25/09/2014, 14:40

We constrain several models of the early Universe that predict statistical anisotropy of the cosmic microwave background (CMB) sky. We make use of WMAP9 and Planck maps deconvolved with beam asymmetries. As compared to previous releases of CMB data, they do not exhibit the anomalously large quadrupole of statistical anisotropy. This allows to strengthen the limits on the parameters of models...

Laura Sagunski
(DESY Hamburg)

25/09/2014, 15:00

We discuss how the time-flow approach of cosmological perturbation theory can be used as a tool for large-scale structure. In particular, we show that the flow equations allow to derive straightforwardly consistency relations for equal-time correlators involving both density and velocity fields and underlying different background cosmologies. Furthermore, we use the time-flow approach to proof...

Isabel Mira Oldengott
(Universität Bielefeld)

25/09/2014, 15:20

Starting from the collisional Boltzmann equation, we derive for the first time and from first principles a Boltzmann hierarchy for neutrinos including neutrino-neutrino interactions mediated by a scalar particle. Such interactions appear, for example, in majoron-like models of neutrino mass generation. In contrast to, e.g., the first-order Boltzmann hierarchy for Thomson-scattering photons,...

Dr
Rajeev Kumar Jain
(CP3-Origins, University of Southern Denmark)

25/09/2014, 16:10

If cosmic magnetic fields are produced during inflation, they are likely to be correlated with the primordial curvature perturbations that are responsible for the Cosmic Microwave Background anisotropies and Large Scale Structure. We compute the three-point cross-correlation function of the curvature perturbation with two powers of the electromagnetic field in a typical model of inflationary...

Dr
Masato Minamitsuji
(CENTRA, Instituto Superior Tecnico)

25/09/2014, 16:55

We investigate the gauge-invariant cosmological perturbations in the gravity and matter frames in the general scalar-tensor theory where two frames are related by the disformal transformation. The gravity and matter frames are the extensions of the Einstein and Jordan frames in the scalar-tensor theory where two frames are related by the conformal transformation, respectively. First, it is...

Koushik Dutta
(Associate Professor)

25/09/2014, 17:10

Even though f(R) modifications of late time cosmology is very successful in explaining the cosmic acceleration, it is very difficult to simultaneously satisfy the fifth-force constraint. Even in this case, the effective scalar degree of freedom may move to a point (close to its minima) in the field space where the Ricci scalar diverges. We elucidate this point further with a specific example...