# Holographic Cosmology v2.0 - 2011

Holographic Cosmology v2.0

## Concluding Remarks

Friday Jun 24, 2011
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## Bubble Popper

Friday Jun 24, 2011
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In the context of the AdS/CFT correspondence, I will discuss model-independent properties shared by bulk theories of gravity with consistent dual descriptions. I will then discuss the prospects of extending these ideas to non-conformal theories, in particular to attempts to realize cosmological theories holographically. I will address the status of in-principle falsifiability of various holographic proposals through internal consistency conditions of the boundary theory.

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## Correlation functions in FRW/CFT duality

Friday Jun 24, 2011
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FRW/CFT duality is a proposal for a holographic dual description for universe created by bubble nucleation. For (3+1) dimensional universe, the dual theory is defined on 2-sphere at the boundary of open universe. I will study correlation functions and explain essential features of FRW/CFT duality: One bulk field corresponds to a tower of CFT operators The boundary theory contains 2D gravity, and the Liouville field plays the role of time. Energy-momentum tensor has dimension 2, as required from the 2D conformal symmetry.

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## A Canonical Measure for Inflation

Friday Jun 24, 2011
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## Challenges in Cosmology

Friday Jun 24, 2011
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An attempt at describing some of the shortcomings in our present understanding of cosmology.

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## A toy model of quantum gravity in cosmological spacetimes

Friday Jun 24, 2011
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In this talk, I attempt to gain insight into the description of quantum gravity on cosmological spacetimes by considering the physics of families of accelerating observers in spacetimes which admit non-perturbative descriptions vis AdS/CFT.

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## Complexity in Fundamental Physics

Thursday Jun 23, 2011
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## Liouville theory and Holographic Cosmology

Thursday Jun 23, 2011
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I will explain how Liouville theory with complex values of its parameters arises naturally in speculative holographic cosmologies. We will encounter Liouville theory of both the spacelike'' and timelike'' variety. I will then use this as motivation to present some new results on the analytic continuation of Liouville theory recently obtained with Maltz and Witten.

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## Dictionaries and Wavefunctions in dS/CFT and AdS/CFT

Thursday Jun 23, 2011
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I discuss bubble collisions from the perspective of an observer in a hat. In particular, I emphasize the breaking and restoration of conformal symmetry, as well as (independence of) initial conditions and rate equations. A cartoon version of the problem, Mandelbrot percolation, makes computations tractable. Enjoyable, even.

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## On the fast scrambling conjecture

Thursday Jun 23, 2011
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Motivated by the consistency of black hole complementarity, Sekino and Susskind have conjectured that no physical system can "scramble" its internal degrees of freedom in time faster than (1/T) log S, where T is temperature and S the system's entropy. By considering a number of toy examples and general Lieb-Robinson-type causality bounds, I'll explore the range of validity of the conjecture. Some of these examples suggest that nonlocal Hamiltonians can delocalize information at rates exceeding the fast scrambling bound, but the physical relevance of these examples is unclear.

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## LECTURES ON-DEMAND

### Avery Broderick: Perimeter Institute and University of Waterloo

Speaker: Avery Broderick