Dielectric Anomaly in Ice near 20 K; Evidence of Macroscopic Quantum Phenomena

TL;DR

This study reports a dielectric anomaly near 20 K in ice, suggesting macroscopic quantum phenomena driven by proton tunneling, with isotope effects observed in heavy ice (D2O).

Contribution

The paper uncovers a dielectric anomaly in ice at low temperatures, providing evidence of macroscopic quantum effects in a natural system, which is rarely observed.

Findings

Anomaly in the imaginary dielectric constant near 20 K in H2O.

No anomaly observed in D2O, indicating isotope effect.

Proton quantum tunneling likely causes the anomaly.

Abstract

H2O is one of the most important substances needed in sustaining life; but yet not much is known about its ground state. Here, a previously unidentified anomaly is identified in the form of a minimum in the imaginary part of the dielectric constant with respect to temperature near 20 K while the real part remains monotonic. Isothermal dispersion and absorption measurements show coinciding results. For the case of heavy ice (D2O), no anomaly was identified confirming an apparent isotope effect. Concerted quantum tunneling of protons is believed to be the main cause behind the reported anomaly. Our findings identify another system that exhibits macroscopic quantum phenomena of which rarely occur in nature.