[Paper Review] Natural and bionic neuronal membranes: possible sites for quantum biology

Lee Smolin|arXiv (Cornell University)|Jan 21, 2020

Photoreceptor and optogenetics research24 references4 citations

TL;DR

This paper proposes two bionic quantum technologies: a hybrid silicon-phospholipid membrane device using 31P nuclear spins as qubits and electron spins as control qubits, and a topological quantum model in neuronal membranes driven by chiral phospholipids. The key contribution is the theoretical proposal that chiral membrane structures may induce Chern-Simons couplings, enabling robust topological qubits protected by geometry and potentially decoupled from thermal noise.

ABSTRACT

A new concept for bionic quantum technology is presented based on a hybrid of a silicon wafer on which is layered a phospholipid membrane, such as is found in biological cell membranes. The phosphorus atoms in the head groups of the membranes carry nuclear spins which serve as memory qubits. The role of control qubits may be played by unpaired spins of extra electrons on phosphate groups with a single negative charge, in polar, zwitterionic headgroups such as phosphatidylcholine (PC). Classical control gates and circuits are embedded on the silicon wafer, as in proposals by Kane and others for solid state quantum computing devices. A proposal to extend these ideas to neuronal membranes, which makes use of the chirality of the phospholipid molecules that make up its bulk, is also briefly sketched. The chirality of the phospholipid molecules is argued, at least at low temperature, to induce Chern-Simons couplings, which may give rise to robust qubits in topological winding states, defined on the cylinder mod punctures-which are the ion channels.

Motivation & Objective

• To explore the feasibility of using natural and artificial neuronal membranes as platforms for quantum information processing.
• To investigate whether phospholipid membranes can host long-lived quantum states via nuclear spin qubits and electron spin control.
• To propose that chiral phospholipid arrangements in neuronal membranes may induce Chern-Simons couplings, enabling topological qubits.
• To assess whether topological winding states in membrane channels could be robust against thermal noise, offering a protected quantum subsystem.
• To lay the conceptual groundwork for quantum biology in biological membranes, particularly in axons.

Proposed method

• A hybrid architecture layers a phospholipid bilayer on a silicon wafer, using 31P nuclear spins in phosphate headgroups as memory qubits.
• Unpaired electron spins on zwitterionic phosphate groups (e.g., phosphatidylcholine) serve as control qubits, analogous to Kane’s solid-state quantum computing proposal.
• Classical control gates and nanowire circuits are etched into the silicon wafer to manipulate electron wavefunctions and mediate entanglement between nuclear spins.
• The bilayer structure provides topological protection for quantum information through spatial separation and shielding of nuclear spins.
• Chirality in phospholipid molecules is proposed to generate effective Chern-Simons terms in the electromagnetic action, leading to topological winding states on cylindrical surfaces with punctures (ion channels).
• The model uses modified Maxwell equations with a topological coupling term proportional to $ b_0 $, suggesting transverse electromagnetic fields can induce or measure topological qubit states.

Experimental results

Research questions

• RQ1 Can phospholipid membranes on silicon wafers host stable, controllable qubits using 31P nuclear spins and electron spins?
• RQ2 Can the chiral structure of neuronal membranes induce topological quantum states via Chern-Simons couplings?
• RQ3 Are the resulting topological winding states sufficiently decoupled from thermal noise to be metastable at physiological temperatures?
• RQ4 Can ion channel dynamics in axons act as a probe or control mechanism for topologically protected qubits?
• RQ5 Is there a protected quantum subsystem in the membrane that could be exploited for noise-resilient quantum information processing?

Key findings

• The 31P nuclear spin in phospholipid headgroups is proposed as a viable memory qubit due to its long coherence time and weak coupling to the environment.
• Unpaired electron spins on zwitterionic phosphate groups can serve as control qubits, enabling entanglement and gate operations via electron wavefunction overlap.
• The bilayer structure may protect quantum information by shielding nuclear spins from environmental decoherence.
• Chirality in phospholipid molecules may induce effective Chern-Simons couplings, leading to topological winding states on the cylinder mod punctures (ion channels).
• A rough estimate suggests the energy gap for topological states could be above room temperature, implying metastability on signal propagation timescales.
• The model suggests that neuronal action potentials may perturb or measure topological qubits via transverse electromagnetic fields generated during ion flow.