## Cosmic Inflation, the Arrow of Time & Boltzmann Brains

The thermodynamic arrow of time offers a very interesting perspective on cosmic inflation and the tuning problems it is meant to address. My research has explored the connection between these two topics from a variety of angles, and I believe further development of these connections will help us attain a deeper understanding of the cosmos and the role of cosmic inflation.

#### Some technical publications

*Cosmic Inflation and the Arrow of Time*, in "Science and Ultimate Reality: Quantum Theory, Cosmology and Complexity", honoring John Wheeler's 90th birthday. J. D. Barrow, P.C.W. Davies, & C.L. Harper eds. Cambridge University Press (2004) astro-ph/0210527 (*This paper is meant to be accessible to a wide range of trained scientists, not just experts in the field. It includes my first written discussion of the connection between inflation and the "Boltzmann Brain" problem.)**Can the universe afford inflation?*- de Sitter equilibrium as a fundamental framework for cosmology (in the proceedings of the DICE2008 conference, Thomas Elze, ed). arXiv:0906.1047
- Eternal Inflation with Arrival Terminals arXiv:1406.7352 Phys.Rev. D91 (2015) 023503
- Tuning, Ergodicity, Equilibrium and Cosmology
__arXiv:1401.7309 Phys.Rev. D91 (2015) 10, 10351__ - Holographic bounds and finite inflation arXiv:1410.6065, Phys. Rev. D 91, 043513 (2015)
- Ludwig Boltzmann
*, On Certain Questions of the Theory of Gases*(Nature, Feb 28, 1895, p413) This is the paper where Boltzmann first mentioned the "Boltzmann Brain Problem" (but he does not call it that).

### Reviews of cosmic inflation

- A. Albrecht Les Houches Lectures on Inflation (slides here) in Post-Planck Cosmology: Lecture notes of the Les Houches Summer School: Volume 100, July 2013 (Oxford, 2015) DOI: 10.1093/acprof:oso/9780198728856.001.0001
*Cosmic Inflation: Open questions and perspectives on future surveys*Cosmological Quests for the Next Decade, Daejeon April 2017 Cosmic Inflation, Reflections on Motivations, Accomplishments and FutureOpportunities- , Advances in Theoretical Cosmology in Light of Data, NORDITA July, 2017, Stockholm

### More accessible information

*Maybe time's arrow needs ergodicity as well as entropy*(Science News April 1 2014)

- Did the Universe Begin? (Closer to Truth interview)

- My review of Sean Carroll's book on the arrow of time in Physics Today

*Big Brain Theory*New York Times 1/15/2008