"Is Quantum Biocomputing ahead of us?"
There has been some work done on biocomputing, quantum computing, spin chemistry, and magnetochemical reactions.
Correlated radical pairs — pairs of transient radicals created simultaneously, such that the 2 electron spins, one on each radical, are correlated — on photoactive magnetoreceptive proteins such as Cryptochromes does not constitute quantum computation.
See: "Light-dependent magnetoreception in birds: analysis of the behaviour under red light after pre-exposure to red light" by W. Wiltschko, Gesson, Noll, and R. Wiltschko in the Journal of Experimental Biology, 2004.
See the article "Vision-based animal magnetoreception" at the QuantBioLab website, Quantum Biology and Computational Physics research group, University of Southern Denmark (SDU):
Figure 6. Shown here is a semi-classical description of the magnetic field effect on the radical pairs between FADH and tryptophan in cryptochrome. The unpaired electron spins (S$_1$ and S$_2$) precess about a local magnetic field produced by the addition of the external magnetic field $B$ with contributions I$_1$ and I$_2$ from the nuclear spins on the two radicals. The spin precession continuously alters the relative spin orientation, causing the singlet (anti-parallel) to triplet (parallel) interconversion which underlies the magnetic field effect. Electron back-transfer from a tryptophan to FADH quenches cryptochrome's active state. However, this back-transfer can only take place when the electron spins are in the singlet state, and this spin-dependence allows the external magnetic field, $B$, to affect cryptochrome activation.
Figure 7. Schematic illustration of a bird's eye and its important components. The retina (a) converts images from the eye's optical system into electrical signals sent along the ganglion cells forming the optic nerve to the brain. (b) An enlarged retina segment is shown schematically. (c) The retina consists of several cell layers. The primary signals arising in the rod and cone outer segments are passed to the horizontal, the bipolar, the amacrine, and the ganglion cells. (d) The primary phototransduction signal is generated in the receptor protein rhodopsin shown schematically at a much reduced density. The rhodopsin containing membranes form disks with a thickness of ~20 nm, being ~15–20 nm apart from each other. The putatively magnetic-field-sensitive protein cryptochrome may be localized in a specifically oriented fashion between the disks of the outer segment of the photoreceptor cell, as schematically shown in panel d or the cryptochromes (e) may be attached to the oriented, quasi-cylindrical membrane of the inner segment of the photoreceptor cell (f).
In mathematical terms, the vision-based compass in birds is characterized by a filter function, which models the magnetic field-mediated visual signal modulation recorded on the bird's retina (see Fig. 8).
Figure 8. Panoramic view at Frankfurt am Main, Germany. The image shows the landscape perspective recorded from a bird flight altitude of 200 m above ground with the cardinal directions indicated. The visual field is modified through the magnetic filter function; the patterns are shown for a bird looking at eight cardinal directions (N, NE, E, SE, S, SW, W, and NW). The geomagnetic field inclination angle is 66°, being a characteristic value for the region.
A biomechanical computer has been created. Bio4Comp, an EU-funded research project, have created biomolecular machines each only a few billionths of a meter (nanometers) in size. The actin-myosin and microtubule-kinesin motility systems can solve problems by moving through a nanofabricated network of channels designed to represent a mathematical algorithm; an approach we termed “network-based biocomputation”. Whenever the biomolecules reach a junction in the network, they either add a number to the sum they are calculating or leave it out. That way, each biomolecule acts as a tiny computer with processor and memory. While an individual biomolecule is much slower than a current computer, they are self-assembling so that they can be used in large numbers, quickly adding up their computing power. An example of how this works is shown in the video on their website.
Are these tools already solving problems you (quantum computing researchers) have?
Is there any specific issue these tools 'must' be solving somehow that you are struggling with at your labs?
Could we use them (although this will imply a paradigm shift towards biotechnology)?
"The first step in solving mathematical problems with network-based biocomputation is to encode the problem into network format so that molecular motors exploring the network can solve the problem. We have already found network encodings for several NP-complete problems, which are particularly hard to solve with electronic computers. For example, we have encoded subset sum, exact cover, boolean satisfiability and travelling salesman.
Within the Bio4Comp project, we will focus on optimizing these encodings so that they can be efficiently solved with biological agents and be more readily scaled up. Analogous to optimized computer algorithms, optimized networks can greatly reduce the computing power (and thus the number of motor proteins) required for finding the correct solution." - Source: Bio4Comp Research.
Another interesting paper which supports my answer that radical pairs don't constitute a quantum computer, but is merely a quantum biochemical reaction demonstrating spin chemistry, is "Quantum probe and design for a chemical compass with magnetic nanostructures" by Jianming Cai (2018).
Introduction. — Recently, there has been increasing interest in quantum biology namely investigating quantum effects in chemical and biological systems, e.g., light harvesting system, avian compass and olfactory sense. The main motivation is to understand how quantum coherence (entanglement) may be exploited for the accomplishment of biological functions. As a key step towards this goal, it is desirable to find tools that can detect quantum effects under ambient conditions. The ultimate goal of practical interest in studying quantum biology is to learn from nature and design highly efficient devices that can mimic biological systems in order to complete important tasks, e.g. collecting solar energy and detecting weak magnetic field.
As an example of quantum biology, the radical pair mechanism is an intriguing hypothesis to explain the ability of some species to respond to weak magnetic fields, e.g. birds, fruit flies, and plants. A magnetochemical compass could find applications in remote magnetometry, in a magnetic mapping of microscopic or topographically complex materials, and in imaging through scattering media. It was demonstrated that a synthetic donor-bridge-acceptor compass composed of a linked carotenoid (C), porphyrin (P), and fullerene (F) can work at low temperature (193 K). It is surprising that such a triad molecule is the only known example that has been experimentally demonstrated to be sensitive to the geomagnetic field (yet not at room temperature). It is currently not known how one might construct a biomimetic or synthetic chemical compass that functions at ambient temperature.
Summary. — We have demonstrated that a gradient field can lead to a significant enhancement of the performance of a chemical compass. The gradient field also provides us with a powerful tool to investigate quantum dynamics of radical pair reactions in spin chemistry. In particular, it can distinguish whether the initial radical pair state is in the entangled singlet state or in the classically correlated state, even in the scenarios where such a goal could not be achieved before. These phenomena persist upon addition of partial orientational averaging and addition of realistic magnetic noise. The effects predicted there may be detectable in a hybrid system compass composed of magnetic nanoparticles and radical pairs in an oriented liquid crystalline host. Our work offers a simple method to design/simulate a biologically inspired weak magnetic field sensor based on the radical pair mechanism with a high sensitivity that may work at room temperature.