Butterfly Velocities for Holographic Theories of General Spacetimes

TL;DR

This paper extends the holographic calculation of butterfly velocities to general spacetimes, revealing universal scaling behaviors and proposing a Lifshitz field theory dual for flat FRW universes.

Contribution

It introduces a method to compute butterfly velocities in non-AdS holography, including operators in entanglement shadows, and applies it to flat FRW spacetimes.

Findings

Butterfly velocities in flat FRW spacetimes show universal scaling.

A Lifshitz z=4 field theory may serve as the dual for these spacetimes.

The method accounts for operators in entanglement shadows.

Abstract

The butterfly velocity characterizes the spread of correlations in a quantum system. Recent work has provided a method of calculating the butterfly velocity of a class of boundary operators using holographic duality. Utilizing this and a presumed extension of the canonical holographic correspondence of AdS/CFT, we investigate the butterfly velocities of operators with bulk duals living in general spacetimes. We analyze some ubiquitous issues in calculating butterfly velocities using the bulk effective theory, and then extend the previously proposed method to include operators in entanglement shadows. We explicitly compute butterfly velocities for bulk local operators in the holographic theory of flat Friedmann-Robertson-Walker spacetimes and find a universal scaling behavior for the spread of operators in the boundary theory, independent of dimension and fluid components. This result may suggest that a Lifshitz field theory with z = 4 is the appropriate holographic dual for these spacetimes.