Black Holes and Quantumness on Macroscopic Scales

TL;DR

This paper models black holes as quantum condensates of gravitons, showing that quantum effects are significant at critical points, which could explain black hole mysteries like the information paradox.

Contribution

It demonstrates that quantum effects are crucial at the critical point in a bosonic model, supporting the idea that black holes exhibit strong quantum behavior even at large scales.

Findings

Quantum entanglement peaks at the critical point.

Long wavelength modes dominate entanglement.

Semiclassical physics breaks down at the critical point.

Abstract

It has recently been suggested that black holes may be described as condensates of weakly interacting gravitons at a critical point, exhibiting strong quantum effects. In this paper, we study a model system of attractive bosons in one spatial dimension which is known to undergo a quantum phase transition. We demonstrate explicitly that indeed quantum effects are important at the critical point, even if the number of particles is macroscopic. Most prominently, we evaluate the entropy of entanglement between different momentum modes and observe it to become maximal at the critical point. Furthermore, we explicitly see that the leading entanglement is between long wavelength modes and is hence a feature independent of ultraviolet physics. If applicable to black holes, our findings substantiate the conjectured breakdown of semiclassical physics even for large black holes. This can resolve long standing mysteries, such as the information paradox and the no-hair theorem.