Entanglement entropy of a quantum unbinding transition and entropy of DNA

TL;DR

This paper explores the relationship between quantum entanglement entropy and DNA melting, revealing that near unbinding transitions, entanglement entropy can become arbitrarily large and negative, which is crucial for understanding phase transitions.

Contribution

It establishes a novel connection between quantum entanglement entropy and classical DNA melting, showing negative entropy as essential for phase transitions.

Findings

Entanglement entropy can be arbitrarily large and negative near unbinding transitions.

Negative entropy is linked to DNA bubble entropy responsible for melting.

Results apply to quantum critical points and first-order transitions in various dimensions.

Abstract

Two significant consequences of quantum fluctuations are entanglement and criticality. Entangled states may not be critical but a critical state shows signatures of universality in entanglement. A surprising result found here is that the entanglement entropy may become arbitrarily large and negative near the dissociation of a bound pair of quantum particles. Although apparently counter-intuitive, it is shown to be consistent and essential for the phase transition, by mapping to a classical problem of DNA melting. We associate the entanglement entropy to a subextensive part of the entropy of DNA bubbles, which is responsible for melting. The absence of any extensivity requirement in time makes this negative entropy an inevitable consequence of quantum mechanics in continuum. Our results encompass quantum critical points and first-order transitions in general dimensions.