Coherent State Description of Gravitational Waves from Binary Black Holes

TL;DR

This paper demonstrates that gravitational waves from binary black holes are well described by coherent states, with quantum effects like squeezing appearing at higher orders, providing a quantum mechanical perspective on classical gravitational wave signals.

Contribution

It introduces a quantum coherent state framework for gravitational waves from binary black holes, highlighting the emergence of squeezed states at next order.

Findings

Coherent states accurately describe classical gravitational waves.

Next-order quantum effects lead to squeezed graviton states.

Estimated squeezing parameter for GW150914 is approximately 10^{-4}.

Abstract

Quantum mechanics is the fundamental framework of nature, and gravitational waves from binary black holes during the inspiral phase should likewise be analyzed quantum mechanically. It is commonly assumed that their classical description corresponds to a coherent state, so any deviation would signal genuinely quantum nature of gravity. We show that the coherent-state description reproduces classical gravitational waves at leading order, while next-order effects generate squeezed states of gravitons. For GW150914, we estimate the squeezing parameter to be $\sim 10^{-4}$. We find that gravitational waves from binary black holes are well described by a coherent state.