Quantum Biology Panel Discussion

10/03/2020

By Cristian Voinea

Is life tied in any way to Quantum Physics? After all, Schrödinger's famous thought experiment involved a fatal superposition for his poor cat. Peter Hore, Chiara Marletto and Vlatko Vedral engaged in a fascinating discussion on this topic at Quantum Information Society's Panel on Quantum Biology.

Peter Hore is a Professor of Chemistry and in his research, he is trying to explain the mechanisms which let migratory songbirds navigate using Earth's magnetic field. He supports the idea that these birds have a 'sixth sense', allowing them to see Earth's magnetic field, which results from coherent superpositions of spins within a blue-light photoreceptor. This idea is not only backed by computer simulations, but also by behavioural experiments which show that songbirds become disoriented in an environment without blue light.

Vlatko Vedral and Chiara Marletto are part of the Frontiers of Quantum Physics research group, whose focus is the universality of Quantum Physics beyond the microscopic world. Their research has vast implications in the biological realm, having worked on experiments on entangling bacteria with photons. One way this could be ground-breaking for Quantum Biology is if it eventually leads to a "Schrödinger's bacterium", where a bacterium is in a superposition of dead and alive.

At a microscopic level, Quantum Mechanics should be able to explain all phenomena. However, this would not justify the study of Quantum Biology if everything could also be described with a classical theory through the Correspondence Principle - which states that we can derive classical physics as an approximation of quantum physics on certain scales. It is therefore essential to investigate whether there are non-trivial quantum effects, such as superposition or entanglement, actively utilised in living organisms. One major example is the magnetic sensing present in migratory songbirds. 

Scientists also suggest that quantum search algorithms are naturally occurring in the human body. There are 4 nucleotides which need to be paired in a certain way during DNA replication - while a classical algorithm needs 3 queries to fully match them, a quantum one would only need 1 query! Such an algorithm would explain why there are 4 bases instead of 2, which would not require anything more advanced than a classical search for maximum efficiency.

All these quantum processes require a coherence time that might not be attainable at the relevant scales for living systems. Even though this is an open-ended question, the general consensus from our panellists was that coherence times for molecules are too short to influence the evolution of life. If so, is consciousness, as an emergent phenomenon, also non-quantum? How does this help us solve the eternal measurement problem?

These are questions that we had great pleasure in discussing with our panellists. We hope our last on-site event of this year gave you some answers, or at least new questions to ask yourself. We would also like to welcome the new committee of the Quantum Information Society and wish them good luck!