Brown-Teitelboim Instantons and the First Law of Thermodynamics of (Anti) de Sitter Space

TL;DR

This paper explores how Brown-Teitelboim instantons in (A)dS spaces relate to the first law of thermodynamics, showing that membrane nucleation accounts for entropy change and has implications for holography and complexity.

Contribution

It demonstrates that the BT instanton action encodes the thermodynamic first law of (A)dS space and links membrane nucleation to entropy change, offering new insights into holography and complexity.

Findings

BT instanton action encodes the first law of thermodynamics.

Membrane nucleation accounts for entropy change in (A)dS space.

Connections to holography and complexity are discussed.

Abstract

We study the instantons (or bounces) in the Brown-Teitelboim (BT) mechanism of relaxation of cosmological constant which is a cosmological version of the Schwinger mechanism. The BT mechanism is a false vacuum decay of (A)dS$_{d+1}$ (and $R^{1, d}$) spaces via spontaneous nucleations of spherical $(d-1)$-branes and thus ostensibly has bearings on (A)dS$_{d+1}$/CFT$_d$ holography. In this paper we focus on the four-dimensional case, although the higher or lower-dimensional generalization is straightforward. As is the case with pair productions near black hole and de Sitter horizons, we show that the BT instanton action for a membrane nucleation encodes the first law of thermodynamics of (Anti) de Sitter space. In particular, the membrane instanton precisely accounts for the change of entropy of (A)dS space before and after nucleation, in good accordance with AdS$_{d+1}$/CFT$_d$ in which the $(d-1)$-branes make up all degrees of freedom of AdS$_{d+1}$ space. In light of this lesser-known perspective presented here we also make remarks on (1) (A)dS/CFT and (2) complexity. For the complexity we observe that the Lorentzian bounce action may have close connection to complexity.