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Holographic Cosmology

COVID-19 information for PI Residents and Visitors

Conference Date: 
Lundi, Juin 22, 2009 (All day) to Vendredi, Juillet 24, 2009 (All day)



Holography is one of the most powerful ideas to emerge in recent years from String/M-theory, and has led both to a radical new approach to quantum gravity, combined with a remarkably powerful calculational tool. It offers an exciting opportunity to tackle the long standing issues of the nature of the big-bang, the initial conditions and fate of the universe, which have recently begun to be explored.


This 5 week workshop will bring together leading researchers working in cosmology, string theory  and quantum gravity in order to understand and develop the implications of holography for the cosmology of the early universe. The program will end with a conference from July 15 - 18 to which outside participants are encouraged to apply.




Confirmed Invited Speakers:

Niayesh Afshordi, Perimeter Institute

Andreas Albrecht, University of California, Davis

Jose L.F. Barbon, IFT - Madrid

Robert Brandenberger, McGill University

Ben Craps, Vrije Universiteit Brussel

Paolo Creminelli, ICTP, Trieste

Sumit Das, University of Kentuky

Ben Freivogel, Berkeley University

Andrew Frey, McGill University

Jaume Garriga, Universitat Autonoma de Barcelona

Simeon Hellerman, University of California, Santa Barbara

Thomas Hertog, APC

Matthew Johnson, Caltech

Matt Kleban, New York University

Lev Kofman, CITA

Don Page, University of Alberta

Malcolm Perry, Cambridge University

Eliezer Rabinovici, Hebrew University

Arttu Rajantie, Imperial College, University of London

Leonardo Senatore, Harvard University

Kostas Skenderis, University of Amsterdam

Takahiro Tanaka, Tokyo University

Marika Taylor, University of Amsterdam

Tanmay Vachaspati, Case Western Reserve University

Herman Verlinde, Princeton University

Alex Vilenkin, Tufts University


Alice Bernamonti, Vrije Universiteit Brussels

Multi-Trace Deformations of AdS/CFT and Spherical D-branes

It has been shown by Hertog and Horowitz that certain AdS boundary conditions allow non-singular initial conditions to evolve into a Big Crunch. To study this kind of cosmological singularities, one can use the dual quantum field theory, where the singularity is manifested by the presence of a multi-trace potential unbounded below. Recently, Craps, Hertog and Turok have proposed two specific models of this type to study the possibility of a Big Crunch/Big Bang transition. For both models, I will provide a D-brane interpretation of the unbounded potential. In particular, I will show that the AdS boundary conditions of interest cause spherical D-branes to be pushed to the boundary of AdS, and that the corresponding potential agrees with the multi-trace deformation of the boundary field theory.

Jose L. Fernandez-Barbon, IFT - Madrid

On the (un)naturalness of Higgs inflation

I discuss the basic model of Higgs inflation, with a large non-minimal curvature coupling,from the point of view of effective field theory. It is pointed out that the effective cutoff scale  is uncomfortably low compared to the inflation scale, thus rendering these models extremely sensitive to the details of the ultraviolet completion.

John T. Giblin Jr., Perimeter Institute

Bubbles in Eternal Inflation: A Classic(al) Effect

Cosmological bubble collisions arising from first order phase transitions are a generic consequence of the Eternal Inflation scenario.  I will present our computational strategy for generating and evolving these bubbles in 3+1 dimensions and in a self-consistently expanding background.  I will show the existence of classical field transitions--the classical nucleation of bubbles during collisions--which can dramatically alter the canonical description of eternal inflation.

Simeon Hellerman, UC Santa Barbara

A universal inequality for CFT and quantum gravity

The holographic duality gives a one-to-one mapping between consistent theories of gravity with AdS_d ground state, and conformal field theories in d-1 dimensions.  Since the latter are unambiguously well-defined, we can use their defining properties to prove rigorous, model-independent theorems covering all quantum gravity theories with negative cosmological constant.

Taking d=3, I will prove in this talk that every two-dimensional CFT contains a primary operator of weight less than C /12   + 0.473695, where C is the sum of right- and left-moving central charges.  Using the AdS/CFT dictionary, this establishes that every theory of quantum gravity in asymptotically AdS space contains some state of mass less than 1 / (4  G), above and beyond the universal sector of boundary metric excitations.

Matthew Johnson, Caltech

Cosmology inside the brane and holography

The spacetime region inside of the event horizons of black holes and branes can be interpreted as an FRW universe with some number of ``extra" dimensions compactified on a sphere whose volume is time-dependent. Generally, the region inside of the horizon, and hence the FRW universe, ends in a spacelike singularity. In asymptotically AdS space, it is possible to describe this universe holographically from the outside in terms of a boundary theory. I speculate on how this very direct analogy between spacetimes with horizons and cosmology could sharpen various questions regarding singularities, observables, and the wave function of the universe. I conclude by contrasting these solutions with those containing a lower dimensional inflating universe, and speculate on the implications for a holographic description of de Sitter space.

Lev Kofman, CITA

Recent works on holographic cosmology

My recent works were on new forms of non-gaussianity in CMB from inflationary physics

Malcolm Perry, Cambridge University

Some hidden symmetry in M-theory

Eliezer Rabinovici, Hebrew University

World sheets for world sheets revisited

Artuu Rajantie, Imperial College, University of London

Non-Gaussianity from non-equilibrium physics

Non-equilibrium processes such as inflationary preheating or the ekpyrotic bounce can turn fluctuations of light scalar fields into potentially highly non-Gaussian curvature perturbations. I show how these perturbations can be calculated at fully non-linear level using lattice field theory simulations. As concrete examples, I present results for preheating in chaotic inflation and resonant curvaton decay.

Marika Taylor, University of Amsterdam

Cosmological gravity and the AdS/CFT correspondence

Recently there has been renewed interest in cosmological gravity, namely 3d gravity coupled to a Chern-Simons term with parameter $\mu$, following claims that at $\mu =1$ the theory becomes chiral and stable. In this talk we will investigate cosmological gravity by setting up a concrete holographic dictionary with a dual 2d field theory and we will demonstrate that the theory is in fact not chiral in the limit $\mu = 1$. Instead our holographic dictionary implies that at $\mu =1$ the dual field theory becomes a logarithmic CFT (LCFT). Our results resolve confusions in the earlier literature and the resulting new class of holographic dualities involving LCFTs may have interesting applications to strongly correlated condensed matter systems.

Herman Verlinde, Princeton

A surprising relation between N=2 gauge theory in 4 dimensions and pure quantum gravity in 3 and 2 dimensions