A quantum phase transition in the one-dimensional water chain

TL;DR

This paper demonstrates a quantum phase transition in a linear water chain, revealing its universality class, symmetry effects, and potential for quantum device applications.

Contribution

It provides the first high-quality wavefunction-based evidence of a quantum phase transition in water chains, classifying it within the (1+1)D Ising universality class.

Findings

Water chain exhibits a quantum phase transition.

Breaking inversion symmetry lifts ground state degeneracy.

Potential for quantum devices due to ferroelectric phases.

Abstract

The concept of quantum phase transitions (QPT) plays a central role in the description of condensed matter systems. In this contribution, we perform high-quality wavefunction-based simulations to demonstrate the existence of a quantum phase transition in a crucially relevant molecular system, namely water, forming linear chains of rotating molecules. We determine various critical exponents and reveal the water chain QPT to belong to the (1+1) dimensional Ising universality class. Furthermore, the effect of breaking symmetries is examined and it is shown that by breaking the inversion symmetry, the ground state degeneracy of the ordered quantum phase is lifted to yield two many-body states with opposite polarization. The possibility of forming ferroelectric phases together with a thermal stability of the quantum critical regime up to ~10 K makes the linear water chain a promising candidate as a platform for quantum devices.