Zenith Grant Awardee

Paul Davies

Arizona State University

Project Title

De Sitter Demons

Project Summary

Historically the first attempt to link agency and physics was Maxwell?s demon. The link between information and thermodynamics has been greatly clarified in recent years by analysis of ?demonic? devices, of which the archetype is Szilard?s engine. Such analyses have been restricted to conventional heat baths and thermodynamic systems, albeit with some extension to the quantum domain. Left out of account so far is application to gravitating systems in which event horizon area plays the role of entropy. We shall apply these new-found insights into demonics to investigate the thermodynamic nature of cosmological horizons. De Sitter space has an associated temperature, in spite of the fact that the de Sitter invariant quantum vacuum state does not correspond to a bath of thermal radiation, but rather renormalizes the cosmological constant. We will address whether the thermal fluctuations associated in de Sitter space can be ?mined? by an information-processing demon and converted to directed work, as in conventional thermodynamics. If so, how does information garnering and erasure react back on the horizon in order to comply with the generalized second law of thermodynamics? The analysis will have implications for agency in the far future universe, such as the possibility of Boltzmann brains.

Technical Abstract

Imprinted in the fading afterglow of the big bang are slight ripples indicating that the universe was born almost but not perfectly smooth. An explanation for the ripples comes from quantum effects during the first split second of cosmic existence, when the universe ?inflated? by a huge factor. Theory suggests that an exponentially expanding universe, known as de Sitter space, possesses an intrinsic temperature by analogy with the Hawking effect for black holes, an assumption that underpins our understanding of the big bang. However, the thermal nature of expanding spaces is a murky subject. This project will clarify it by asking: could an intelligent agent harness the heat of de Sitter space to perform work? Long ago Maxwell proposed a ?demon? ? a tiny being who could manipulate molecules and violate the second law of thermodynamics. Recently, demonic devices have been demonstrated in the laboratory. Insights from these trailblazing experiments will be used to test whether de Sitter heat is ?real?. In the far future too, the universe will resemble de Sitter space, but with a growth rate now measured in billions of years. We will analyze whether agency may be sustained indefinitely by ?demonically? mining the thermal energy of space.