The quantum coherent robin red-breast…….Credit: NWFS
In a sense most science and technology news is made up of tidbits, bits and pieces of research. Some of the tidbits are choice morsels, others are insight resistant gristle, and perhaps even more are pure confection. What’s generally missing in the news is how (or if) the tidbit fits into a larger piece or the whole enchilada (to use an expression). This fitting into a whole is difficult, even the experts in a field don’t always know how all the various pieces of research integrate – if they do at all. So consider this piece of news as a tidbit that may be part of a potentially very important whole: Robins use quantum physics for navigation.
First, let’s deal with what robins do. They migrate. They fly thousands of miles from northern lands (Canada, Scandinavia) to warmer winter climes in Africa and southern United States, and then they go back in the spring to breed. Like many other birds, they tend to fly back to places they have been before. How do they do that?
Scientists have long suspected that birds have ‘built-in compasses’ of some kind. Over the years through many experiments, it’s become a fairly sure thing that most birds use the Earth’s magnetic fields to guide them over long distances. It’s called magnetoreception and in many species, including the robin, it takes place in the eyes. It’s known to be a chemical process of some kind but the details have remained murky.
Now a team of researchers from Oxford University (UK) and Singapore University have, at least, put a label onto the murky process: Quantum coherence. In a paper to be published in Physical Review Letters, based on experiments on robins performed by Oxford and Frankfurt scientists, Erik Gauger (Oxford) and Simon Benjamin (Singapore) noted that when the robins were subjected to electromagnetic noise – even at extremely low levels – their navigation system failed to work properly. In fact, the levels of interference were so small that only a quantum level system would be sensitive enough to pick it up.
Gauger and Benjamin believe that molecules in the bird’s eyes use quantum coherence, which in a nutshell is about the ability of electrons to follow paths that interfere with each other, sometimes destructively and sometimes perfectly coherent (a pure state). Normally quantum coherence operates at the subatomic level, but some very important technology is based on larger scale coherent effects such as lasers, superconductivity and superfluidity. Now scientists are beginning to find the effects at the molecular level in biological systems.
‘Progress in this area is proving to be very difficult because the phenomena that must be harnessed are extremely delicate. It would normally be thought almost inconceivable that a living organism could have evolved similar capabilities.’
Co-author Simon Benjamin from Singapore explained: ‘Coherent quantum states decay very rapidly, so that the challenge is to hold on to them for as long as possible. The molecular structures in the bird’s compass can evidently keep these states alive for at least 100 microseconds, probably much longer.’
‘While this sounds like a short time, the best comparable artificial molecules can only manage 80 microseconds at room temperature. And that’s in ideal laboratory conditions.’
[Source: Oxford Science Blog]
This research work, which is still very much in progress, is one of several that involve surprisingly sophisticated use of quantum coherence (or quantum entanglement) in biological processes. Several instances have already been posted here at SciTechStory:
It’s way too early to evaluate the discoveries of quantum effects in biology, but even the first signs are portentous.