Jim Al-Khalili on why quantum biology matters: “The payback if it’s true is huge”
I had been on the phone to physics professor, author and TV presenter Jim Al-Khalili for seven minutes and eight seconds before I realised I was monstrously out of my depth. This was a problem, as I had another 18 minutes to go. “So if you see an effect that’s due to quantum tunnelling and replace hydrogen with deuterium,” he explains, “you can determine whether or not quantum tunnelling is what’s happening as you’ll see the effect go down when you double the mass of the particle.”
Don’t close the page! It will all make sense in time – this is Al-Khalili’s speciality. In his own words, he likes to “give people a headache” before seeing people have a mini-Eureka moment in his chosen area of expertise: quantum physics.
So let’s back up. Al-Khalili is talking about quantum biology: a fascinating field of science that for myriad reasons is tough to research. Before the call – a pre-brief interview ahead of his talk at New Scientist Live – I watched his TED Talk from two years ago on quantum biology. I’ve embedded the video below if you want the briefing in his own words, but the main takehome of things is this: the mad things that happen in the subatomic level – particles existing in more than one place at the same time (superpositions) or being able to pass through an impenetrable barrier (quantum tunneling) – seem to take place within our cells. In other words, quantum isn’t just something for physicists to worry about, anymore: it’s biologists’ problem too.
To give three examples from the above talk, quantum tunnelling seems to play a part in DNA mutations; photons follow multiple routes in photosynthesis with quantum coherence; and even robins are said to use quantum entanglement within the retina to navigate, based on the Earth’s magnetic field.
“Al-Khalili’s contention is that this is worth fighting for. Or it might not be – you can take the man out of quantum physics, but you can’t take quantum physics out of the man.”
People have known this is a possibility for decades, but progress is slow for a number of reasons: chiefly among these is the fact that quantum physics experiments are notoriously difficult to do. They can, as Al-Khalili explains, “be destroyed simply by the act of looking at them,” and that’s in a hugely controlled environment, without the squishy messiness that living cells bring to proceedings. “The big question now is to understand how life can maintain these quantum effects for biological timescales when everything is so noisy and turbulent and warm and complex inside a living cell,” he explains.
“Physicists work very hard to try and isolate these quantum effects, doing their experiments in a vacuum at zero degrees, isolating their instruments from the surroundings, and still, it’s quite elusive.”
The next issue is that these questions have been almost entirely the preserve of physicists for the past century. It requires a co-operation across disciplines which is a challenge, to say the least.
“The physicists will tell you ‘why bother venturing into the messy world of biology when, if it were that easy, we’d have built quantum computers by now? We’re working really hard at controlling everything, and we’re still finding quantum effects illusive,’” says Al-Khalili. “And the biologists will say ‘quantum mechanics? Not in my lab, matey thankyouverymuch.’ And the chemists will say ‘What’s all the fuss about? Everything is quantum, everything is chemistry anyway, what are you getting excited about?’”
It’s the resistance of biologists, however, which is the biggest barrier to overcome, Al-Khalili reckons. “They will resist it. They’ll say ‘we haven’t had to use quantum physics since the birth of genetics and molecular biology, don’t tell us now we have to learn all this nonsense about cats in boxes and whatever.'” I can’t say that I blame them.
Al-Khalili’s contention is that this is worth fighting for. Or it might not be – you can take the man out of quantum physics, but you can’t take quantum physics out of the man.
Why does quantum biology matter?
“Part of the problem is that even those of us who work here aren’t 100%,” he says. “We’re not evangelically preaching that this is the next big breakthrough in science – it may well not be.
“It might well turn to be a red herring. But it’s interesting enough and exciting enough that however speculative it might be, it’s worth pursuing – even to rule it out. Because of the payback if it’s true is big.”
How big? Al-Khalili has two main reasons as to why he’s devoted so much of his life to popularising this cause. First, because it means that some of the big answers of quantum physics may be almost literally under our noses. “If we’re developing sensors and new quantum technologies – trying to build a quantum computer. Well, if life has solved these problems, maybe there’s something we can learn that will help us.”
But perhaps more importantly, it might give us a hitherto unimaginable insight into what makes life special: something so speculative that it’s hard to know its ultimate potential. “So far, we’ve not been able to create artificial life – the only way to make life is through other life,” he explains. “What is it that differentiates a living system from an inanimate system of equivalent complexity? How does the living system maintain this high level of order to keep going?”
But if quantum experiments are hard enough in the physics lab, how do you begin to tackle things with our biology tools? Take the robins mentioned above: how can you tell whether the retina is actually performing quantum reactions or not? “I don’t think it’s impossible, but we have to be more imaginative,” Al-Khalili says. “We can’t learn more about quantum entanglement by putting a bird in a lab… we can test if a bird is sensitive to a magnetic field, but we don’t learn anything about how it uses this chemical compass – for that we’d probably have to isolate the protein and study it separately outside of the bird. And of course, then it becomes a lot more difficult to say definitively ‘yep, this is what’s going on when it’s inside the bird’s retina.’”
Making the public love physics
If this all seems confusing: good. It should do. Al-Khalili is fond of quoting Niels Bohr, the father of quantum mechanics who once said: “If you think you can talk about quantum theory without feeling dizzy, you haven’t understood the first thing about it.”
But Al-Khalili is a quantum physicist by training. I ask how has he found having to get his head around biology. “A challenge,” he replies. “My background is nuclear physics, so when I talk about quantum tunnelling, I’m thinking about alpha decay, alpha radioactivity, alpha particles tunnelling out of an atomic nucleus. But the equations are the same, and they’ll be the same for quantum tunnelling in DNA.
“But all the surroundings, the infrastructure, the environments the numbers you put in, all of that – the biochemistry is completely new to me. I’ve come to the conclusion that biochemistry is the hardest discipline in science. It’s layers upon layer of ‘this, because this, because of this’ – how an enzyme works, or the process of photosynthesis or metabolism. It’s so complex, it makes quantum mechanics look easy in comparison!”
“I’ve come to the conclusion that biochemistry is the hardest discipline in science.”
It’s probably just what people are used to I guess, and Al-Khalili has spent the past 25 years making quantum physics (more) comprehensible to the public. How has he managed it? In part, he puts this down to the natural intellectual curiosity of the people who seek out his talks and TV appearances. “The feedback I get is that viewers of my programmes on BBC Four will be ‘make me feel clever’. They want something hard to grasp, and people appreciate they’re not going to understand all the subtleties without years of study, but that’s fine. They want to be challenged and stretched beyond the mundane: it’s magical and mysterious.”
Sometimes that involves finding analogies that you would never find in a science textbook, of course. “When I talk about quantum tunnelling, with particles disappearing in one place and reappearing somewhere else, it doesn’t make sense,” he says.
“But if I say it’s like a phantom that can walk through a solid wall, people begin to understand. It’s not exactly that, but that’s more or less what’s happening. A particle is also a wave, and a wave can leak through impenetrable barriers in a way that a solid particle can’t. So rather like throwing a ball at a wall and it never being able to get through to the other side, a ghost can leak through.”
Finding analogies that click is kind of like the Eureka moment you might get in the lab. “With a live audience, you can tell with the body language that something has struck a chord, and that’s it: it becomes part of my armoury to use in writing, talks and on TV.”
The possibilities hidden away in living cells may require a whole new set of analogies and rules to explain to the layperson, but there’s no question that Al-Khalili would relish the opportunity to translate what’s going on. Although that does involve us finding out within our lifetimes.
New Scientist Live runs for the until Sunday at the ExCeL Centre in London. Tickets are available here.