The Dynamical Ensemble of the Posner Molecule is not Symmetric

TL;DR

This study reveals that the Posner molecule predominantly adopts low-symmetry structures at room temperature, challenging previous assumptions of high symmetry and impacting its potential as a biological quantum qubit.

Contribution

The paper demonstrates through simulations that the Posner molecule mainly exists in low-symmetry configurations, contradicting prior high-symmetry assumptions used in quantum biological models.

Findings

Posner molecule mainly assumes low-symmetry structures at room temperature.

Previous high-symmetry assumptions are not supported by simulation data.

Implications for the molecule's viability as a quantum information processor.

Abstract

The Posner molecule, $\text{Ca}_9(\text{PO}_4)_6$, has long been recognized to have biochemical relevance in various physiological processes. It has found recent attention for its possible role as a biological quantum information processor, whereby the molecule purportedly maintains long-lived nuclear spin coherences among its ${^{31}\text{P}}$ nuclei (presumed to be symmetrically arranged), allowing it to function as a room temperature qubit. The structure of the molecule has been of much dispute in the literature, although the $\text{S}_6$ point group symmetry has often been assumed and exploited in calculations. Using a variety of simulation techniques (including ab initio molecular dynamics and structural relaxation), rigorous data analysis tools and by exploring thousands of individual configurations, we establish that the molecule predominantly assumes low symmetry structures ($\text{C}_\text{s}$ and $\text{C}_\text{i}$) at room temperature, as opposed to the higher symmetry configurations explored previously. Our findings have important implications on the viability of this molecule as a qubit.