Date 
Room 
Speaker 
Title 
Dec 16 2016
11:00 
Euler Lecture Hall, ICTP

Matteo Viel
()

Using the Lymanalpha forest to address the nature of dark matter 
ABSTRACT: I will discuss recent results in the field of intergalactic medium cosmology and how small scale properties of the transmitted flux can constrain the dark matter properties. 
Dec 02 2016
11:00 
SISSA, Big meeting room

Jin U Kang
()

TBA 
ABSTRACT: TBA 
Nov 25 2016
11:00 
SISSA, Big meeting room

Matt Visser
(Victoria University of Wellington)

Twisted black holes are unphysical 
ABSTRACT: Twisted black holes were proposed by Zhang (1609.09721 [grqc]), and studied by Chen and Jing (1610.00886 [grqc]), and by Ong (1610.05757 [grqc]). These spacetimes are certainly Ricciflat, but are merely minor variants on TaubNUT spacetime. They exhibit several unphysical features that make them quite unreasonable as realistic astrophysical objects. Twisted black holes are not (globally) asymptotically flat. They contain closed timelike curves that are not hidden behind any event horizon  the most obvious of these closed timelike curves are small azimuthal circles around the rotation axis, but the effect is more general. The entire region outside the horizon is infested with closed timelike curves.
(I will discuss how it is easy to see that there is something very unusual about these twisted black holes; and then give elementary arguments for the pathology. I will also discuss how fast things can now change due to existence of the arXiv — see arXiv:1610.06135 [grqc].) 
Nov 18 2016
11:00 
Euler Lecture Hall ICTP

Francesca Lepori
(SISSA)

A model independent method for the AlcockPaczynski test 
ABSTRACT: The AlcockPaczynski (AP) test is a purely geometric test of the cosmic expansion. It consists of measuring the ratio between the radial and transverse size of an intrinsically isotropic object. A suitable target for the AP test is the Baryon Acoustic Oscillations (BAO) feature in the galaxy 2point correlation function. After giving a brief introduction to the implication of BAO measurements for cosmology, I will discuss a method for the AP test applied to the BAO peak, which does not require any prior assumption on the cosmological parameters. I will show how this method is affected by redshift space distortions, gravitational lensing, galaxy bias and the projection effect introduced by a radial window function. (Based on https://arxiv.org/abs/1606.03114) 
Nov 04 2016
11:00 
SISSA, Big meeting room

Dionigi Benincasa
(SISSA)

Computing Entanglement Entropy from Correlation Functions 
ABSTRACT: After giving a brief introduction to the notion of entanglement entropy, I will discuss a recent result due to R. Sorkin that allows one to compute entanglement entropy of a quantum field directly from correlation functions. Unlike the von Neumann formula where an entropy is assigned to density matrices living on a Cauchy surface, C, this formula assigns an entropy to spacetime regions, R. The two entropies coincide when R is globally hyperbolic with Cauchy surface C. If time permits I will then discuss a peculiar property of Sorkin’s entropy applied to quantum fields living on discrete Lorentz invariant spacetimes, where the notion of state at a moment of time does not exist. 
Oct 21 2016
11:00 
ICTP, Euler Lecture Hall

Leonardo Trombetta
()

DE from non local effective actions of gravity 
ABSTRACT: In this journal club I will talk about some attempts to describe dark energy with non local effective actions for the (classical) metric. These kind of modifications generically arise when integrating out quantum fields in curved spaces. Loosely based on [arXiv:1606.08784], I will first give a brief introduction and motivation, and then discuss some models in FRW spacetimes, some of which have an interesting phenomenology. 
Sep 23 2016
10:00 
Euler Lecture Hall ICTP

Andrei Khmelnitsky
()

Relaxing the cosmological constant 
ABSTRACT: We propose a technically natural scenario whereby an initially large cosmological constant (c.c.) is relaxed down to the observed value due to the dynamics of a scalar evolving on a very shallow potential. The model crucially relies on a sector that violates the null energy condition (NEC) and gets activated only when the Hubble rate becomes sufficiently small  of the order of the present one. As a result of NEC violation, this lowenergy universe evolves into inflation, followed by reheating and the standard Big Bang cosmology. The symmetries of the theory force the c.c. to be the same before and after the NECviolating phase, so that a latetime observer sees an effective c.c. of the correct magnitude. Importantly, our model allows neither for eternal inflation nor for a set of possible values of dark energy, the latter fixed by the parameters of the theory. 
Jul 22 2016
11:00 
ICTP  Euler Lecture hall

Paolo Creminelli
(ICTP)

joint SISSA/ICTP APPcosm JC 
ABSTRACT: paper to be discussed: https://arxiv.org/abs/1602.03520 
Jul 08 2016
11:00 
Big meeting room  SISSA

Thomas Jacques
(SISSA)

Simplified models vs EFTs for DM searches at the LHC (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: EFTs and, more recently, simplified models have become a popular way to constrain dark matter at the LHC in a way designed to be as modelagnostic as possible. I will discuss the construction and usage of these models, the theoretical problems with these techniques, and some ways to fix them. 
Jun 24 2016
11:00 
ICTP  Euler Lecture hall

Pietro Baratella
(SISSA)

TBA (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: TBA 
Jun 10 2016
11:00 
Big meeting room  SISSA

Costantino Pacilio, Vedran Skrinjar
(SISSA)

TBA (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: TBA 
May 27 2016
11:00 
ICTP  Euler Lecture hall

Andr Benevides, Lorenzo Bordin
()

TBA (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: TBA 
May 20 2016
11:00 
Big meeting room  SISSA

Mauro Valli
(SISSA)

TBA (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: TBA 
Apr 29 2016
11:00 
ICTP  Euler Lecture hall

Paolo Creminelli
(ICTP)

TBA (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: TBA 
Apr 15 2016
11:00 
Big meeting room  SISSA

Ernesto Lopez Fune
(SISSA)

TBA (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: TBA 
Apr 08 2016
11:00 
Big meeting room  SISSA

Mauro Valli
(SISSA)

TBA (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: TBA 
Apr 01 2016
11:00 
ICTP  Euler Lecture hall

André Benevides, Lorenzo Bordin
(SISSA)

TBA (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: TBA 
Mar 04 2016
11:00 
ICTP  Euler Lecture hall

Emiliano Sefusatti
()

TBA (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: TBA 
Feb 19 2016
11:00 
Big meeting room  SISSA

Alejandro Castedo
(SISSA)

TBA (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: TBA 
Feb 05 2016
11:00 
ICTP  Euler Lecture hall

Vid Irsic
(ICTP)

Lyman alpha forest: from small to large scales (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: The last decade has witnessed an enormous progress in the cosmological\r\ninvestigation of the intergalactic medium (IGM) as probed by the\r\nLymanalpha forest. In my talk I will review the current status of the\r\nfield and give a brief historical overview of how the cosmological focus\r\nof the field has evolved form studying small scales to large scales. I\r\nwill conclude by presenting calculations of the Lymanalpha flux\r\nfluctuations with full relativistic corrections (to first order), and its\r\napplication to the crosscorrelation functions. 
Jan 22 2016
11:00 
Big meeting room  SISSA

Marco Letizia
(SISSA)

Lorentz violation in gravity: the case of EinsteinAether theory (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: After introducing EinsteinAether theory as a framework to incorporate Lorentz violation in gravity, I will discuss its relation to HoravaLifshitz gravity and some of the consequences of introducing a preferred frame in the context of single field inflation. 
Jan 15 2016
11:00 
ICTP  Euler Lecture hall

Jin U Kang
()

Effective dynamics of cosmological fields in a thermal background (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: 
Dec 11 2015
11:00 
Big meeting room

Teresa Bautista Solans
(ICTP)

Weyl Anomalies and Quantum Cosmology (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: I will talk about the cosmological consequences of Weyl anomalies arising from the renormalization of composite operators in a theory of gravity with a cosmological constant. Near two dimensions, the relevant anomaly can be computed explicitly using results from Liouville theory and leads to a nonlocal quantum effective action. The resulting quantum energy momentum tensor is nonlocal and leads to a decaying vacuum energy in a homogeneous and isotropic expanding universe.
I will discuss a generalization of these results to four dimensions and possible implications for inflation, the cosmological constant problem, and de Sitter spacetime. 
Nov 27 2015
11:00 
ICTP  Euler Lecture hall

Takeshi Kobayashi
(SISSA)

Constraints on Primordial Magnetic Fields from Inflation (joint SISSA/ICTP APPcosm JC) 
ABSTRACT: After introducing observational hints for the existence of cosmologicalscale magnetic fields, I will discuss how the inflationary epoch can magnetize our universe, and also discuss general constraints on primordial magnetic fields from inflation. 
Feb 04 2015
14:00 
Room 005

Alessio Belenchia
(SISSA)

Analogue gravity: kinematical and dynamical analogues 
ABSTRACT: I will do a short review of some analogue gravity model, from classical to quantum systems. The focus will be both on systems that present kinematical features analogue to quantum field theory in curved spacetime, and systems that share dynamical features analogous to gravity theories. The former being relevant for understanding key features of effects such as Hawking radiation and the latter as toy models for the emergent spacetime paradigm.http://www.sissa.it/app/images/okicon.png 
Sep 11 2014
14:00 
room 005

Kirill Krasnov
(University of Nottingham)

Gravity as a Gauge Theory 
ABSTRACT: I will describe how geometry and its dynamics can be described using an SU(2) gauge field instead of the metric. This works in 4 spacetime dimensions and is based on the selfduality. One of the advantages of this new gaugetheoretic formalism is that the (linearised) description of gravitons is much simpler than in the metric language. This simplicity relies on a certain complex of differential operators. 
Jul 02 2014
12:00 
room 128

Alessandro Lovato
(Physics Division, Argonne National Laboratory)

Electroweak response functions: from Carbon12 to Neutron Matter 
ABSTRACT: I will report on an ab initio calculation of the Carbon12 chargernform factor and sum rules of electromagnetic and neutralcurrent responsernfunctions. The longitudinal elastic form factor and the electromagnetic sumrnrules are found to be in satisfactory agreement with available experimentalrndata. The transverse electromagnetic and neutral current sum rules receivernlarge contributions from the twobody currents. In the Electromagnetic casernthey are needed for a better agreement with experimental data; this factrnmay have implications for the anomaly observed in recent neutrinornquasielastic chargechanging scattering data off Carbon12.rnThe role played by nuclear correlations is discussed in both Carbon12 andrnneutron matter case. In particular, I will show how the neutrino mean freernpath in cold neutron matter turns out to be strongly affected by both shortrnand long range correlations, leading to a sizable increase with respect tornthe prediction of the Fermi gas model.rnPreliminary results on the neutral current euclidean response function ofrnCarbon12 will also be shown. 
May 07 2014
14:00 

Jacobo López Pavón
(SISSA)

Lowscale minimal seesaw models vs Neff 
ABSTRACT: I will start discussing why and how the Standard Model (SM) has to be extended in\r\norder to accommodate neutrino masses, introducing at the same time the most popular models regarding this issue. After that I will focus on the TypeI seesaw models, which are the most simple extensions of the SM that can explain neutrino masses. In this models, the SM field content is minimally extended with fermion singlets (sterile neutrinos) and a New Physics scale, M, associated to their physical masses is introduced. This scale is introduced to account for neutrino masses and usually assumed to be much larger than the electroweak scale. However, these models can explain neutrino masses for any value of M above $O(eV)$ up to $O(10^{15} GeV)$. The seesaw scale is presently unconstrained and its determination is one of the most important questions in neutrino physics. Paying special attention to the contribution of the sterile states to $N_{eff}$ as a function of M, I will show that a large part\r\n(8 orders of magnitude) can be excluded thanks to cosmological measurements. 
Apr 16 2014
14:00 

Eolo Di Casola
(SISSA)

The Enchanting Carousel: A bird's eye view of Gödel's universe 
ABSTRACT: We shall give a glance at few key aspects of Gödel's solution of Einstein's equations (structure of the spacetime, relations with other relevant cosmological models, interpretation, pitfalls), possibly discussing its emergence in the context of extended theories of gravity. 
Apr 09 2014
14:00 

Maria Archidiacono
(Aarhus University)

Neutrinos and the interplay between cosmology and particle physics 
ABSTRACT: In the last few years the imprint of light sterile neutrinos on cosmological data sets has been deeply investigated within the framework of different theoretical scenarios. Nevertheless the question whether cosmology can accommodate the existence of additional neutrinos is still open. The strong dependence of the results on the underlined cosmological model and on the included data sets contributes to a puzzling scenario. Recently the discovery of Bmodes in the polarization of the Cosmic Microwave Background has reopened the debate, providing new life to light sterile neutrinos and their unique imprinting on CMB as a dark radiation component. I will review the status of the cosmological constraints on light sterile neutrinos, focussing the discussion on the consistency with neutrino oscillation experiments. 
Feb 12 2014
14:00 
SISSA, Room 005

Marko Simonović
(SISSA)

Consistency Relations for Cosmological Perturbations  from Inflation to Galaxies 
ABSTRACT: 
Jan 28 2014
14:00 
SISSA, Room 005

Matteo Martinelli
(SISSA)

Dark Energy: an overview 
ABSTRACT: 
Dec 17 2013
14:00 
SISSA, Room 005

Dionigi Benincasa
(SISSA)

Causal Set Quantum Gravity: an overview 
ABSTRACT: 
Nov 27 2013
13:30 
TBA

Piero Ullio
(SISSA)

Recent developments in direct Dark Matter search 
ABSTRACT: 
Jun 07 2013
9:30 
Euler Room, ICTP

Dario Bettoni
(SISSA)

Probing Dark Energy through Scale Dependence, Observables and unobservables in dark energy cosmologies 
ABSTRACT: 
May 08 2013
13:30 
Room 005

Michele Lucente
(SISSA)

Sterile Neutrino Oscillations: The Global Picture 
ABSTRACT: Neutrino oscillations involving eVscale neutrino mass states are investigated in the context of global neutrino oscillation data including short and longbaseline accelerator, reactor, and radioactive source experiments, as well as atmospheric and solar neutrinos. We consider sterile neutrino mass schemes involving one or two masssquared differences at the eV^2 scale denoted by 3+1, 3+2, and 1+3+1. We discuss the hints for eVscale neutrinos from nu_e disappearance (reactor and Gallium anomalies) and nu_mu>nu_e appearance (LSND and MiniBooNE) searches, and we present constraints on sterile neutrino mixing from nu_mu and neutralcurrent disappearance data. An explanation of all hints in terms of oscillations suffers from severe tension between appearance and disappearance data. The best compatibility is obtained in the 1+3+1 scheme with a pvalue of 0.2% and exceedingly worse compatibilities in the 3+1 and 3+2 schemes. 
Apr 12 2013
9:00 
ICTP

Paolo Creminelli
(ICTP)

Entanglement entropy in de Sitter space 
ABSTRACT: We compute the entanglement entropy for some quantum field theories on de Sitter space. We consider a superhorizon size spherical surface that divides the spatial slice into two regions, with the field theory in the standard vacuum state. First, we study a free massive scalar field. Then, we consider a strongly coupled field theory with a gravity dual, computing the entanglement using the gravity solution. In even dimensions, the interesting piece of the entanglement entropy is proportional to the number of efoldings that elapsed since the spherical region was inside the horizon. In odd dimensions it is contained in a certain finite piece. In both cases the entanglement captures the long range correlations produced by the expansion. 
Apr 12 2013
10:30 
ICTP

Emiliano Sefusatti
(ICTP)

Planck 2013 Results. XXIV. Constraints on primordial nonGaussianity 
ABSTRACT: The Planck nominal mission cosmic microwave background (CMB) maps yield\r\nunprecedented constraints on primordial nonGaussianity (NG). Using three\r\noptimal bispectrum estimators, separable templatefitting (KSW), binned, and\r\nmodal, we obtain consistent values for the primordial local, equilateral, and\r\northogonal bispectrum amplitudes, quoting as our final result f_NL^local=2.7\r\n+/ 5.8, f_NL^equil= 42 +/ 75, and f_NL^ortho= 25 +/ 39 (68% CL\r\nstatistical); and we find the IntegratedSachsWolfelensing bispectrum\r\nexpected in the LambdaCDM scenario. The results are based on comprehensive\r\ncrossvalidation of these estimators on Gaussian and nonGaussian simulations,\r\nare stable across component separation techniques, pass an extensive suite of\r\ntests, and are confirmed by skewC_l, wavelet bispectrum and Minkowski\r\nfunctional estimators. Beyond estimates of individual shape amplitudes, we\r\npresent modelindependent, threedimensional reconstructions of the Planck CMB\r\nbispectrum and thus derive constraints on earlyUniverse scenarios that\r\ngenerate primordial NG, including general singlefield models of inflation,\r\nexcited initial states (nonBunchDavies vacua), and directionallydependent\r\nvector models. We provide an initial survey of scaledependent feature and\r\nresonance models. These results bound both general singlefield and multifield\r\nmodel parameter ranges, such as the speed of sound, c_s geq 0.02 (95% CL), in\r\nan effective field theory parametrization, and the curvaton decay fraction r_D\r\ngeq 0.15 (95% CL). The Planck data put severe pressure on ekpyrotic/cyclic\r\nscenarios. The amplitude of the fourpoint function in the local model tau_NL<\r\n2800 (95% CL). Taken together, these constraints represent the highest\r\nprecision tests to date of physical mechanisms for the origin of cosmic\r\nstructure. 
Mar 20 2013
13:30 
7th floor big meeting room  SISSA

Bethan Cropp
(SISSA)

From configuration to dynamics  Emergence of Lorentz signature in classical field theory 
ABSTRACT: The Lorentzian metric structure used in any field theory allows one to implement the relativistic notion of causality and to define a notion of time dimension. This article investigates the possibility that at the microscopic level the metric is Riemannian, i.e. locally Euclidean, and that the Lorentzian structure, that we usually consider as fundamental, is in fact an effective property that emerges in some regions of a 4dimensional space with a positive definite metric. In such a model, there is no dynamics nor signature flip across some hypersurface; instead, all the fields develop a Lorentzian dynamics in these regions because they propagate in an effective metric. It is shown that one can construct a decent classical field theory for scalars, vectors and (Dirac) spinors in flat spacetime. It is then shown that gravity can be included but that the theory for the effective Lorentzian metric is not general relativity but of the covariant Galileon type. The constraints arising from stability, the equivalence principle and the constancy of fundamental constants are detailed and a phenomenological picture of the emergence of the Lorentzian metric is also given. The construction, while restricted to classical fields in this article, offers a new view on the notion of time. 
Feb 27 2013
13:30 
SISSA  Room 137

Giulio D'Odorico
(SISSA)

Black holes and entanglement entropy 
ABSTRACT: I will give an overview of some recent papers (1302.1878, 1212.6824) discussing the renormalization of entanglement entropy, the relation with its thermodynamical counterpart for black hole spacetimes, and the possible insights given by the renormalization group. If I have time, I will also briefly review what has been found recently (1212.1821) in the context of asymptotically safe gravity. 
Feb 15 2013
9:30 
Euler Room, ICTP

Emanuele Castorina
(SISSA)

Statistical ensembles of virialized halo matter density profiles 
ABSTRACT: We define and study statistical ensembles of matter density profiles describing spherically symmetric, virialized dark matter haloes of finite extent with a given mass and total gravitational potential energy. We provide an exact solution for the grand canonical partition functional, and show its equivalence to that of the microcanonical ensemble. We obtain analytically the mean profiles that correspond to an overwhelming majority of microstates. All such profiles have an infinitely deep potential well, with the singular isothermal sphere arising in the infinite temperature limit. Systems with virial radius larger than gravitational radius exhibit a localization of a finite fraction of the energy in the very center. The universal logarithmic inner slope of unity of the NFW haloes is predicted at any mass and energy if an upper bound is set to the maximal depth of the potential well. In this case, the statistically favored mean profiles compare well to the NFW profiles. For very massive haloes the agreement becomes exact. 
Feb 08 2013
10:00 
Room 005

Federico Urban
(Universite' Libre de Bruxelles)

Cosmic Rays with Telescope Array 
ABSTRACT: I will review the current state of art in the cosmic rays business and the latest results from Telescope Array from a newcomer point of view. 
Jan 30 2013
13:30 
VII floor meeting room (SISSA)

Gabriele Trevisan
(SISSA)

Anomalous Dimensions and NonGaussianity 
ABSTRACT: We analyze the signatures of inflationary models that are coupled to strongly interacting field theories, a basic class of multifield models also motivated by their role in providing dynamically small scales. Near the squeezed limit of the bispectrum, we find a simple scaling behavior determined by operator dimensions, which are constrained by the appropriate unitarity bounds. Specifically, we analyze two simple and calculable classes of examples: conformal field theories (CFTs), and largeN CFTs deformed by relevant timedependent doubletrace operators. Together these two classes of examples exhibit a wide range of scalings and shapes of the bispectrum, including nearly equilateral, orthogonal and local nonGaussianity in different regimes. Along the way, we compare and contrast the shape and amplitude with previous results on weakly coupled fields coupled to inflation. This signature provides a precision test for strongly coupled sectors coupled to inflation via irrelevant operators suppressed by a high mass scale up to 1000 times the inflationary Hubble scale. [Ref. 
Jan 18 2013
9:30 
ICTP

Neil Barnaby
(University of Cambridge, DAMTP)

New Sources of Cosmological Fluctuations from Inflation 
ABSTRACT: Primordialrngravitational waves are key observable relics of the early universe,rnand might be detected in the near future via the Bmode polarization ofrnthe CMB. Gravitational waves are inevitably generated during inflationrnas quantum fluctuations of the metric; their detection would constitute arnmeasurement of the fundamental energy scale of inflation. In this talk Irnwill discuss the possibility that additional modeldependent sources ofrngravitational waves could provide a competative signal, weakening thernlink between the Bmode polarization and the scale of inflation. I willrnshow that simple particle production models do not source an importantrncontribution to the gravitational wave spectrum on CMB scales, butrnfeatures and nonGaussianity in the scalar sector might be detectable. 
Dec 12 2012
13:30 
Room 137

Marko Simonovic
(SISSA)

Stochastic Bias from NonGaussian Initial Conditions 
ABSTRACT: In this talk I will discuss recently proposed stochastic scaledependent bias as a probe for primordial nonGaussianities for a particular class of inflationary models. I will show how a stochastic form of scaledependent halo bias can arise in multisource inflationary models, where multiple fields determine the initial curvature perturbation. After a brief derivation of the effect for general nonGaussian initial conditions, I will focus on some examples where this effect can be large. The study of a collapsed limit of the four point function is of a particular interest since, at lowest order, this is the regime in which the stochasticity arises if the collapsed limit is boosted relative to the square of the threepoint function in the squeezed limit.[ 
Nov 30 2012
9:30 
Luigi Stasi Room  ICTP

David Marzocca
(SISSA)

Higgs mass and vacuum stability in the Standard Model 
ABSTRACT: I will review the paper 1205.6497, where the authors present the\r\n stateoftheart computation of the Higgs potential in the Standard\r\n Model and discuss its stability in the light of the recent\r\n measurement of the Higgs mass at about 126GeV. I will then discuss\r\n some implications and possible applications of this work in the\r\n context of Higgs inflation, supersymmetry and neutrino physics. 
Nov 30 2012
10:15 
Luigi Stasi Room  ICTP

Emiliano Sefusatti
(ICTP)

The BOSS Lymanalpha Forest Sample from SDSS Data Release 9. 
ABSTRACT: We present the BOSS Lymanalpha (Lya) Forest Sample from SDSS Data Release 9, comprising 54,468 quasar spectra with zqso > 2.15 suitable for Lya forest analysis. This data set probes the intergalactic medium with absorption redshifts 2.0 < z_alpha < 5.7 over an area of 3275 square degrees, and encompasses an approximate comoving volume of 20 h^3 Gpc^3. With each spectrum, we have included several products designed to aid in Lya forest analysis: improved sky masks that flag pixels where data may be unreliable, corrections for known biases in the pipeline estimated noise, masks for the cores of damped Lya systems and corrections for their wings, and estimates of the unabsorbed continua so that the observed flux can be converted to a fractional transmission. The continua are derived using a principal component fit to the quasar spectrum redwards of restframe Lya (lambda > 1216 Ang), extrapolated into the forest region and normalized by a linear function to fit the expected evolution of the Lya forest meanflux. The estimated continuum errors are ~5% rms. We also discuss possible systematics arising from uncertain spectrophotometry and artifacts in the flux calibration; global corrections for the latter are provided. Our sample provides a convenient starting point for users to analyze clustering in BOSS Lya forest data, and it provides a fiducial data set that can be used to compare results from different analyses of baryon acoustic oscillations in the Lya forest. The full data set is available from the SDSSIII DR9 web site. 
Nov 07 2012
13:30 
Big Meeting Room VII floor

Daniele Gaggero
(SISSA)

Cosmic rays propagation in the galaxy 
ABSTRACT: I will give a brief overview on the propagation of Cosmic Rays (CR) in the turbulent magnetic field of the Galaxy.\r\nFirst, I will present in detail the diffusionloss equation describing the process and I will describe DRAGON, the recently developed numerical code that solves this equation for all CR species under very general assumptions.\r\nThen, I\'ll discuss some relevant results obtained with the code with particular focus on: 1) the maximum likelihood analysis we performed to constrain the free parameters involved in the problem and the best model we found, which is compatible with most CR observables; 2) the solution we proposed to a couple of longstanding puzzles in CR physics, i.e. the gradient problem and the anisotropy problem.\r\nIn the last part of the talk I will briefly present some interesting recent results on leptonic species, in particular the positron excess measured by both PAMELA and FermiLAT, and the anisotropy upper limits released by FermiLAT, with a small discussion on the future projects (and future updates of the code) related to these topics. 
Oct 24 2012
13:30 
7th floor Big meeting room

ShuangYong Zhou
(SISSA)

Aspects of Galileon Field Theory 
ABSTRACT: The Galileon model was inspired by the braneworld DGP model and was originally proposed as infrared modifications to General Relativity. Various extensions have been investigated, both from a phenomenological and field theoretical point of view. I will try to give a broader picture while focusing on my work on this area. 
Jun 06 2012
13:00 
Big Meeting Room

Carlo Pagani
(SISSA)

f(R) Gravity from the renormalisation group 
ABSTRACT: We explore the cosmological dynamics of an effective f(R) model rnconstructed from a renormalisation group (RG) improvement of the EinsteinHilbert action, using the nonperturbative beta functions of the exact renormalisation group equation. The resulting f(R) model has some remarkable properties. It naturally exhibits an unstable de Sitter era in the ultraviolet (UV), dynamically connected to a stable de Sitter era in the IR, via a period of radiation and matter rndomination, thereby describing a nonsingular universe. We find that the UV de Sitter point is one of an infinite set, which make the UV RG fixed point inaccessible to classical cosmological evolution. In the vicinity of the fixed point, the model behaves as R^2 gravity, while it correctly recovers General Relativity at solar system scales. In this simplified model, the fluctuations are too large to be the observed ones, and more ingredients in the action are needed. 
May 30 2012
13:00 
Room 135

Aseem Paranjape
(ICTP)

Bayesian physical reconstruction of initial conditions from large
scale structure surveys 
ABSTRACT: We present a fully probabilistic, physical model of the nonlinearly evolved density field, as probed by realistic galaxy surveys. Our model is valid in the linear and mildly nonlinear regimes and uses second order Lagrangian perturbation theory to connect the initial conditions with the final density field. Our parameter space consists of the 3D initial density field and our method allows a fully Bayesian exploration of the sets of initial conditions that are consistent with the galaxy distribution sampling the final density field. Our method naturally and accurately reconstructs nonlinear features corresponding to threepoint and higher order correlation functions such as walls and filaments. Simple tests of the reconstructed initial conditions show statistical consistency with the Gaussian simulation inputs. Our test demonstrates that statistical approaches based on physical models of the large scale structure distribution are now becoming feasible for realistic current and future surveys. arXiv1203.3639 
May 16 2012
13:00 
7th floor Big Meeting Room

Yabebal Fantaye
(SISSA)

A measurement of gravitational lensing of the microwave background using South Pole Telescope data 
ABSTRACT: We use South Pole Telescope data from 2008 and 2009 to detect the
nonGaussian signature in the cosmic microwave background (CMB)
produced by gravitational lensing and to measure the power spectrum of
the projected gravitational potential. We constrain the ratio of the
measured amplitude of the lensing signal to that expected in a
fiducial LCDM cosmological model to be 0.86 +/ 0.16, with no lensing
disfavored at 6.3 sigma. Marginalizing over LCDM cosmological models
allowed by the WMAP7 results in a measurement of A_lens=0.90+/0.19,
indicating that the amplitude of matter fluctuations over the redshift
range 0.5 <~ z <~ 5 probed by CMB lensing is in good agreement with
predictions. We present the results of several consistency checks.
These include a clear detection of the lensing signature in CMB maps
filtered to have no overlap in Fourier space, as well as a "curl"
diagnostic that is consistent with the signal expected for LCDM. We
perform a detailed study of bias in the measurement due to noise,
foregrounds, and other effects and determine that these contributions
are relatively small compared to the statistical uncertainty in the
measurement. We combine this lensing measurement with results from
WMAP7 to improve constraints on cosmological parameters when compared
to those from WMAP7 alone: we find a factor of 3.9 improvement in the
measurement of the spatial curvature of the Universe,
Omega_k=0.0014+/0.0172; a 10% improvement in the amplitude of matter
fluctuations within LCDM, sigma_8=0.810+/ 0.026; and a 5% improvement
in the dark energy equation of state, w=1.04+/0.40. When compared
with the measurement of w provided by the combination of WMAP7 and
external constraints on the Hubble parameter, the addition of the
lensing data improve the measurement of w by 15% to give
w=1.087+/0.096.
arxiv:1202.0546 
Apr 18 2012
13:00 
7th floor Big Meeting Room

Emiliano Sefusatti
(ICTP)

The BOSS papers 
ABSTRACT: The clustering of galaxies in the SDSSIII Baryon Oscillation Spectroscopic Survey: measurements of the growth of structure and expansion rate at z=0.57 from anisotropic clustering arXiv:1203.6641,
The clustering of galaxies in the SDSSIII Baryon Oscillation Spectroscopic Survey: cosmological implications of the largescale twopoint correlation function
arXiv:1203.6616
The clustering of galaxies in the SDSSIII Baryon Oscillation Spectroscopic Survey: a large sample of mock galaxy catalogues arXiv:1203.6609
The clustering of galaxies in the SDSSIII Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in the Data Release 9 Spectroscopic Galaxy Sample
arXiv:1203.6594

Mar 28 2012
13:00 
room 005

Gabrijela Zaharijas
(ICTP)

Fermi Bubbles in the Milky Way: the closest AGN feedback
laboratory courtesy of Sgr A*? 
ABSTRACT: Deposition of a massive ($10^4$ to $10^5 \msun$) giant molecular cloud (GMC) into the inner parsec of the Galaxy is widely believed to explain the origin of over a hundred unusually massive young stars born there $\sim 6$ Myr ago. An unknown fraction of that gas could have been accreted by Sgr A*, the supermassive black hole (SMBH) of the Milky Way. It has been recently suggested that two observed $\gamma$rayemitting bubbles emanating from the very center of our Galaxy were inflated by this putative activity of Sgr A*. We run a suite of numerical simulations to test whether the observed morphology of the bubbles could be due to the collimation of a wide angle outflow
from Sgr A* by the disclike Central Molecular Zone (CMZ), a well known massive repository of molecular gas in the central $\sim 200$ pc. We find that an Eddingtonlimited outburst of Sgr A* lasting $\simeq 1$ Myr is required to reproduce the morphology of the {\it Fermi} bubbles, suggesting that the GMC mass was $\sim 10^5 \msun$ and it was mainly accreted by Sgr A* rather than used to make stars. We also find that the outflow from Sgr A* enforces strong angular momentum mixing in the CMZ disc, robustly sculpting it into a much
narrower structure  a ring  perhaps synonymous with the recently reported "Herschel ring". In addition, we find that Sgr A* outflow is likely to have induced formation of massive starforming GMCs in the CMZ. In this scenario, the Arches and Quintuplet clusters, the two observed young star clusters in the central tens of parsecs of the Galaxy, and also GMCs such as Sgr B2, owe their existence to the recent Sgr A* activity., arXiv:1203.3060 
Mar 21 2012
13:00 
Room 005

Dario Bettoni
(SISSA)

Cleaning up the cosmological constant 
ABSTRACT: We present a novel idea for screening the vacuum energy contribution to the overall value of the cosmological constant, thereby enabling us to choose the bare value of the vacuum curvature empirically, without any need to worry about the zeropoint energy contributions of each particle. The trick is to couple matter to a metric that is really a composite of other fields, with the property that the squareroot of its determinant is the integrand of a topological invariant, and/or a total derivative. This ensures that the vacuum energy contribution to the Lagrangian is nondynamical. We then give an explicit example of a theory with this property that is free from Ostrogradski ghosts, and is consistent with solar system physics and cosmological tests. arXiv:1203.1040v1 
Feb 29 2012
13:00 
7th floor Big Meeting Room

Matteo Martinelli
(SISSA)

Constraining Modified Gravity and Coupled Dark Energy with
Future Observations 
ABSTRACT: Satellite missions as the ongoing Planck experiment and the proposed
weak lensing Euclid survey are expected to provide the strongest
constraints on a wide set of cosmological parameters.
These missions can offer the opportunity either to test general
relativity on cosmic scales through mapping of the galaxy weak lensing
signal either to test possible couplings between dark energy and dark
matter. In this talk I will discuss the ability of these experiments
to constrain modified gravity scenarios, in particular those predicted
by f(R) theories, and coupled dark energy.
I will show that Euclid will improve constraints expected from the PLANCK
satellite on these models by several orders of magnitude.
I will also discuss parameter degeneracies and the possible
biases introduced by these modifications to the standard picture. 
Feb 22 2012
13:00 
7th floor Big Meeting Room

Andrzej Hryczuk
(SISSA)

Asymmetric Higgsino Dark Matter 
ABSTRACT: In the supersymmetric framework, a higgsino asymmetry exists in the universe before the electroweak phase transition. We investigate whether the higgsino is a viable asymmetric dark matter candidate. We find that this is indeed possible. The gauginos, squarks and sleptons must all be very heavy, such that the only electroweakscale superpartners are the higgsinos. The temperature of the electroweak phase transition must be in the (110) GeV range. arXiv1201.2699 
Feb 08 2012
13:00 
7th Floor Big Meeting Room

Giorgio Arcadi
(SISSA)

A WIMPy Baryogenesis miracle 
ABSTRACT: Y. Cui, L. Randall, B. Shuve: arxiv.1112.2704"Generally, baryogenesis and the establishment of the dark matter density are treated as independent processes. Recent work on asymmetric dark matter shows that connections between the dark and visible sectors might account for the similarity in the energy densities of baryonic and dark matter. In this paper, we explore a
very different possible connection, in which weakly interacting massive particle (WIMP) dark matter annihilation is also directly responsible for baryogenesis. We call this process "WIMPy baryogenesis". The dark matter relic density in these models, as with
conventional WIMP models, is obtained with only order one couplings and TeVscale masses according to the WIMP miracle. Thus, WIMPy baryogenesis models naturally accommodate weakscale dark matter, in contrast with many asymmetric dark matter models. Furthermore, in WIMPy baryogenesis the observed baryon asymmetry is simultaneously obtained together with the correct dark matter abundance, which is the "miracle" of WIMPy baryogenesis. The models we present have the further feature that they create the baryon number asymmetry at the weak scale, thereby avoiding the problems in some models of
baryogenesis associated with high reheat temperatures in supersymmetric theories. Some of these models yield observable
consequences in ongoing and future experiments." 
Jan 25 2012
13:00 
7th Floor Large Meeting Room

Alioscia Hamma
(Perimeter Institute)

The fast scrambling conjecture 
ABSTRACT: In this talk, I will discuss the recent paper arxiv:1111.6580, where the authors propose that Black Holes are fast scramblers. A fast scrambler is a quantum device that is able to totally mix the reduced system of a pure quantum state in the shortest possible time. This property is connected as we also discuss in the other talk to a strong form of thermalization. It is conjectured that Black Holes are the fastest scrambles in nature, namely they can scramble quantum information in a time that scales logarithmically with the system size.

Jan 18 2012
13:00 
7th Floor Large Meeting Room

Maryam Tavakoli
(SISSA)

"FermiLAT constraints on dark matter annihilationcross section with the Fornax cluster" and "Evidence for extended gammaray emission from galaxy cluster" 
ABSTRACT: Shin'ichiro Ando and Daisuke Nagai, arXiv.1201.0753
Jiaxin Han, Carlos S. Frenk, Vincent R. Eke, Liang Gao, Simon
D. M. White, arXiv.1201.1003 
Jan 11 2012
13:00 
7th Floor Large Meeting Room

Eolo di Casola
(SISSA)

Lorentz violating kinematics: Threshold theorems 
ABSTRACT: Recent tentative experimental indications, and the subsequent theoretical speculations, regarding possible violations of Lorentz invariance have attracted a vast amount of attention. An important technical issue that considerably complicates detailed calculations in any such scenario, is that once one violates Lorentz invariance the analysis of thresholds in both scattering and decay
processes becomes extremely subtle, with many new and naively unexpected effects. In the current article we develop several extremely general threshold theorems that depend only on the existence of some energy momentum relation E(p), eschewing even assumptions of isotropy or monotonicity. We shall argue that there are physically
interesting situations where such a level of generality is called for,
and that existing (partial) results in the literature make unnecessary technical assumptions. Even in this most general of settings, we show that at threshold all final state particles move with the same 3velocity, while initial state particles must have 3velocities
parallel/antiparallel to the final state particles. In contrast the various 3momenta can behave in a complicated and counterintuitive manner.
arXiv.1111.6340 
Jun 29 2011
13:00 
SISSA, Large meeting room, 7th Floo

Cristiano Germani
(LMU, Muenchen)

UVProtected Inflation 
ABSTRACT: In Natural Inflation, the Inflaton is a pseudoNambuGoldstone boson which acquires a mass by explicit breaking of a global shift symmetry at scale f. In this case, for small field values, the potential is flat and stable under radiative corrections. Nevertheless, slow roll conditions enforce f>>M_p making the validity of the whole scenario questionable. In this talk, I will introduce the gravitationally enahnced friction mechanism that allows to take f<arXiv:1012.0853 
Jun 22 2011
13:00 
SISSA, room 005

Paolo Creminelli
(ICTP)

On graviton nonGaussianities during inflation. The PseudoConformal Universe: Scale Invariance from Spontaneous Breaking of Conformal Symmetry. 
ABSTRACT: On graviton nonGaussianities during inflation.
Juan M. Maldacena, (Princeton, Inst. Advanced Study) , Guilherme L. Pimentel, (Princeton U.).
PUPT2371, Apr 2011. 50pp.
ePrint: arXiv:1104.2846 [hepth]
The PseudoConformal Universe: Scale Invariance from Spontaneous Breaking of Conformal Symmetry.
Kurt Hinterbichler, Justin Khoury, . Jun 2011. 49pp. Temporary entry
ePrint: arXiv:1106.1428 [hepth] 
Jun 08 2011
13:00 
7th Floor Large Meeting Room

Dario Bettoni
(SISSA)

Can dark matter be a BoseEinstein condensate? 
ABSTRACT: P.H.Chavanis, arXiv.1103.2050
P.H. Chavanis, arXiv:1103.2698
T. Harko, arXiv:1105.5198 
Apr 15 2011
11:00 
SISSA, room 137

Stefano Giaccari
(SISSA)

Hidden Conformal Symmetry of the Kerr Black Hole 
ABSTRACT: Extreme and verynearextreme Kerr black holes have been conjectured to be holographically dual to twodimensional CFTs by studying a near horizon scaling region where two copies of the Virasoro algebra can be defined. I will review a paper ( arXiv:1004.0996v1 [hepth] ) in which the authors observe that at low frequencies the scalar wave equation is solved by hypergeometric functions, which suggests the existence of a hidden conformal symmetry. This fact allows them to conjecture that the Kerr black hole is dual to a 2D CFT even for generic mass M and angular momentum J. 
Apr 06 2011
13:00 
SISSA, 7th Floor Large Meeting Room

Ravi Sheth
(ICTP)

ArXiv:1012.1335 
ABSTRACT: In standard gravity and with gaussian initial conditions, halo (and hence galaxy) bias is independent of scale, at least on very large scales. This is not true in most departures from the standard model. Reference paper: arXiv:1012.1335.
I'd discuss scaledependent halo bias in this and other models. 
Mar 30 2011
13:00 
SISSA, 7th Floor Large Meeting Room

Carlo Baccigalupi
(SISSA)

On the way to detect B modes from inflation: issues and data analysis approaches 
ABSTRACT: http://xxx.lanl.gov/abs/1103.2554 
Mar 02 2011
13:00 
SISSA, Library reading room

Paolo Salucci
(SISSA)

A Novel Test of the Modified Newtonian Dynamics with Gas Rich Galaxies 
ABSTRACT: http://www.astro.umd.edu/~ssm/papers/PhysRevLett_2011_inpress.pdf 
Feb 23 2011
13:00 
SISSA, Library reading room

Christopher Eling
(SISSA)

From NavierStokes to Einstein 
ABSTRACT: Everyday fluids are welldescribed by the incompressible NavierStokes equations. Although the equations are simple to state, they are very
interesting in both physics and mathematics due to turbulence and the existence and smoothness problems. In the past few years a connection to
another set of nonlinear PDE's, the Einstein equations, has been developed out of the AdS/CFT correspondence in string theory but goes back to
observations about the dynamics of black holes from the 1970's. I will review these works and then describe the recent paper, http://arxiv.org/abs/1101.2451 which constructs a geometry "dual" to solutions of the NS equations. 
Feb 09 2011
13:00 
SISSA, Library reading room

Martin Spinrath
(SISSA)

Search for Supersymmetry in pp Collisions at 7 TeV in Events with Jets and Missing Transverse Energy 
ABSTRACT: CMS collaboration, arXiv:1101.1628

Dec 14 2010
0:00 
SISSA, Library reading room

Jason Dick
(SISSA)

Concentric circles in WMAP data may provide evidence of violent
preBigBang activity 
ABSTRACT: http://xxx.lanl.gov/abs/1011.3706
Authors: V.G.Gurzadyan, R.Penrose
as well as related papers.

Jun 25 2010
13:00 
SiSSA, Room 128

Maryam Tavakoli
(SISSA)

PAMELA through a Magnetic Lense 
ABSTRACT: http://arxiv.org/abs/1005.4668 
Apr 08 2010
13:00 
SISSA, Reading Room

Barbara Sartoris
(OATS)

The potential of Xray cluster surveys to constrain primordial nonGaussianity 
ABSTRACT: http://arxiv.org/abs/1003.0841 
Mar 30 2010
16:00 
ICTP, Seminar Room

Alvaro De Rujula
(CERN, Geneva, Switzerland)

Higgs impostors at the LHC 
ABSTRACT: 
Mar 18 2010
13:00 
SISSA, Reading Room

Jorge Noreńa
(SISSA)

NonGaussianity in the LargeScale Structure 
ABSTRACT: NonGaussianity is the deviation of the distribution of primordial cosmological perturbations from a Gaussian. The observation of nonGaussianity can be a powerful test and probe of inflation, it can be useful for distinguishing inflation from competing frameworks and putting constraints in inflationary models. Recently, there has been much interest in the study of the effects that nonGaussianity can have on the large scale structure as a complementary alternative to the constraints on nongaussianity from the CMB. I will explain the physical effects that lead to the modification of the LSS and briefly comment on recent observational bounds and future possibilities.
Some recent references:
http://arxiv.org/abs/1003.0841
http://arxiv.org/abs/1001.5217 
Mar 04 2010
13:00 
SISSA, Reading Room

Alessandro Lovato
(SISSA)

Composition and thermodynamics of nuclear matter with light clusters 
ABSTRACT: http://arxiv.org/abs/0908.2344 
Feb 18 2010
13:00 
SISSA, Reading Room

Guido D'Amico
(SISSA)

Symmetron Fields: Screening LongRange Forces Through Local Symmetry Restoration 
ABSTRACT: http://arxiv.org/abs/1001.4525 
Feb 04 2010
13:00 
SISSA, Reading Room

Samuel Leach
(SISSA)

SevenYear Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation 
ABSTRACT: http://arxiv.org/abs/1001.4538 
Jan 28 2010
13:00 
SISSA, Reading Room

Adriano Contillo
(SISSA)

Asymptotically Safe Inflation 
ABSTRACT: http://arxiv.org/abs/0911.3165 
Jan 14 2010
13:00 
SISSA, Reading Room

Piero Ullio
(SISSA)

Open discussion on the CDMS paper and outlook for dark matter searches 
ABSTRACT: http://arxiv.org/abs/0912.3592 
Dec 10 2009
13:00 
SISSA, Reading Room

Angus James Prain
(SISSA)

Informationtheoretic natural ultraviolet cutoff for spacetime 
ABSTRACT: http://arxiv.org/abs/0908.3061 
Oct 22 2009
13:00 
SISSA, Reading Room

Aseem Paranjape
(ICTP)

Averaging and backreaction in cosmology 
ABSTRACT: The averaging problem in cosmology has attracted attention recently as a possible means of explaining the late time acceleration of the universe. I will briefly go through the arguments that lead to this proposal. I will then argue that when calculated carefully, the effect (socalled backreaction) of averaging cosmological inhomogeneities, is in fact very small (of order ~10^4 today). Moreover, linear cosmological perturbation theory (PT) appears to be stable against the inclusion of the backreaction. The enhancement from nonlinear scales is also expected to be small, which is justified by studying the structure of the backreaction integrals in linear PT, and by exact toy models of nonlinear structure growth.
Hence backreaction cannot be large enough to explain the dark energy phenomenon.
It remains to be seen however, whether this small backreaction can lead to observable signatures. One possibility is the enhancement due to nonlinearities mentioned above, which could be probed more carefully in Nbody simulations. Another interesting effect, in the radiation dominated era, is a (tiny!) modification of the equation of state of radiation due to an interaction with the backreaction terms.
I will discuss a few ideas relating to each of these.
References :
http://arxiv.org/abs/0811.2619
http://arxiv.org/abs/0906.3165 
May 07 2009
13:00 
SISSA, reading room

Marco Serone
(SISSA)

Quantum Gravity at a Lifshitz Point 
ABSTRACT: ArXiv:0901.3775 [hepth] 
Apr 30 2009
13:00 
SISSA, reading room

Vincenzo Vitagliano
(SISSA)

On the relation between the isotropy of the CMB and the geometry of the Universe 
ABSTRACT: Http://arxiv.org/abs/0903.3013 
Apr 23 2009
13:00 
SISSA, reading room

Claudia Hagedorn
(SISSA)

Hybrid natural inflation from non Abelian discrete symmetry 
ABSTRACT: ArXiv:0902.4676 [hepph] 
Apr 02 2009
13:00 
SISSA, Reading Room

Adriano Contillo
(SISSA)

Warmintermediate Inflationary Universe Model 
ABSTRACT: ArXiv:0903.4214 
Mar 19 2009
13:00 
SISSA, reading room

Serena Fagnocchi
(Enrico Fermi Ctr., Rome & Bologna U. & INFN, Bologna)

Numerical observation of Hawking radiation from acoustic black holes in atomic BECs 
ABSTRACT: New J.Phys.10:103001,2008.
ePrint: arXiv:0803.0507 [condmat.other] 
Mar 12 2009
13:00 
SISSA, Reading Room

Matteo Viel
(OAT)

Recent Results in Intergalactic Cosmology 
ABSTRACT: 
Feb 26 2009
13:00 
SISSA, Reading Room

Omar Zanusso
(SISSA)

"Running Inflation in the Standard Model"
Authors: Andrea De Simone, Mark P. Hertzberg, Frank Wilczek 
ABSTRACT: ArXiv:0812.4946 
Feb 19 2009
13:00 
SISSA, Reading Room

Samuel Leach
(SISSA)

Can the WMAP Haze really be a signature of annihilating neutralino dark matter?
Authors: Daniel T. Cumberbatch, Joe Zuntz, Hans Kristian Kamfjord Eriksen, Joe Silk 
ABSTRACT: ArXiv:0902.0039 