Why You Should Care About Quantum Neuroscience

Hints of an incredibly exciting future

Posted Dec 31, 2018

In case you haven’t heard, Quantum science is white hot right now, with excited talk of unimaginably powerful quantum computers, ultra-efficient quantum communication and impenetrable cyber security through quantum encryption.

Why all the hype? 

Simply put, Quantum science promises giant leaps forward instead of the baby steps we have grown accustomed to through everyday science. Everyday science, for example, gives us new computers that double in power every 2-3 years, whereas Quantum science promises computers with many trillions of times more power than the most muscular computer available today.

In other words Quantum science, if successful, will produce a seismic shift in technology that will reshape the world as we know it, in even more profound ways than the Internet or smartphones did.

The breathtaking possibilities of Quantum science all arise from one simple truth: quantum phenomena completely break the rules that limit what “classical” (normal) phenomena can accomplish. 

Two examples where Quantum science makes what used to be impossible suddenly possible, are quantum superposition and quantum entanglement.

Let's tackle quantum superposition first.

In the normal world, an object such as a baseball can only be in one place at one time. But in the quantum world, a particle such as an electron can occupy an infinite number of places at the same time, existing in what physicists call a superposition of multiple states. So in the quantum world, one thing sometimes behaves like many different things.

CC0
Superposition
Source: CC0

Now let's examine quantum entanglement by extending the baseball analogy a little further. In the normal world two baseballs sitting in dark lockers in major league stadiums in Los Angeles and Boston are totally independent of each other, such that if you opened one of the  storage lockers to look at one baseball, absolutely nothing would happen to the other baseball in a dark storage locker 3,000 miles away. But in the quantum world, two individual particles, such as photons can be entangled, such that the mere act of sensing one photon with a detector instantaneously forces the other photon, no matter how far away, to assume a particular state. 

Such entanglement means that in the quantum universe, multiple distinct entities can sometimes behave as a single entity, no matter how far apart the distinct entities are. 

This would be the equivalent of changing the state of one baseball—say, forcing it to be on the top vs. bottom shelf of a storage locker—simply by opening a storage locker 3,000 miles away and gazing at an entirely different baseball.

These “impossible” behaviors make quantum entities ideal for doing the impossible with, for example, computers. In normal computers a stored bit of information is either a zero or a one, but in a quantum computer a stored bit, called a Qubit (quantum bit), is both zero and one at the same time. Thus, where a  simple memory store of 8 bits can contain any individual number from 0 to 255 (2^8=256) a memory of  8 Qubits can store 2^8= 256 separate numbers all at once! The ability to store exponentially more information is why quantum computers promise a quantum leap in processing power.

In above example, an 8 bit memory in a quantum computer stores 256 numbers between 0 and 255 all at once while an 8 bit memory in an ordinary computer stores only 1 number between 0 and 255 at a time. Now imagine a 24 bit quantum memory ( 2^24=16,777,216 ) with only 3 times as many Qubits as our first memory: it could store a whopping 16,777,216 different numbers at once! 

Which brings us to the intersection of Quantum science and neurobiology. The human brain is a far more powerful  processor than any computer available today: does it achieve some of this awesome power by harnessing quantum weirdness in the same way that quantum computers do?

Up until very recently, physicists’ answer to that question has been a resounding “No.”

Quantum phenomena such as superposition rely on isolating those phenomena from the surrounding environment, particularly heat in the environment that sets particles in motion, upsetting the hyper-delicate quantum house of cards of superposition and forcing a particular particle to occupy either point A or point B, but never both at the same time. 

Thus, when scientists study quantum phenomena they go to great lengths to isolate the material they’re studying from the surrounding environment, usually by lowering the temperature in their experiments to nearly absolute zero. 

But evidence is mounting from the world of plant physiology that some biological processes that rely on quantum superposition occur at normal temperatures, raising the possibility that unimaginably strange world of quantum mechanics may indeed intrude into the every day workings of other biological systems, such as our nervous systems.

For example, in May 2018 a research team at Groningen University that included physicist Thomas la Cour Jansen found evidence that plants and some photosynthetic bacteria achieve nearly 100% efficiency converting sunlight to useable energy by exploiting the fact that absorption of solar energy causes some electrons in light-capturing molecules to simultaneously exist in both excited and non-excited quantum states spread across relatively long distances inside the plant, allowing the light-excited electrons to find the most efficient path from the molecules where light is captured to different molecules where usable energy for the plant is created.

Evolution, in its relentless quest to engineer the most energy-efficient life forms, appears to have ignored physicists’ belief that useful quantum effects can’t happen in the warm, wet environments of biology.

The discovery of quantum effects in plant biology has given rise to an entirely new field of science called quantum biology. In the past few years, quantum biologists have unearthed evidence of quantum mechanical properties in magnetic field perception in the eyes of some birds (enabling the birds to navigate during migration), and in the activation of smell receptors in humans. Vision researchers have also discovered that photoreceptors in the human retina are capable of generating electrical signals from the capture of a single quanta of light energy.

Did evolution also make our brains hyper-efficient at generating useable energy or transmitting and storing information among neurons using quantum effects such as superposition and entanglement?

Neuroscientists are at the very beginning of investigating this possibility, but I for one am excited about the nascent field of quantum neuroscience because it could lead to jaw-dropping breakthroughs in our understanding of the brain. 

I say this because the history of science teaches us that the biggest breakthroughs almost always come from ideas that, before a particular breakthrough occurs, sound incredibly weird. Einstein’s discovery that space and time are really the same thing (general relativity) is one example, Darwin’s discovery that humans evolved from more primitive life forms, is another. And of course, Planck, Einstein and Bohr’s discovery of quantum mechanics in the first place, is yet another.

All of which strongly implies that the ideas behind tomorrow’s game changing advances in neuroscience, today will seem to most people to be highly unorthodox and improbable. 

Now, just because quantum biology in the brain sounds weird and improbable doesn’t automatically qualify it to be the source of the next giant leap forward in neuroscience. But I have a hunch that a deeper understanding of quantum effects in living systems will yield important new insights about our brains and nervous systems, if for no other reason, that adopting a quantum point of view will cause neuroscientists to look for answers in strange and wonderful places they never considered investigating before. 

And when investigators look into those strange and wonderful phenomena, those phenomena, might, like their entangling cousins in particle physics, look back at them!

References

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3768233/

https://phys.org/news/2016-02-evidence-vibration-theory.html

http://jgp.rupress.org/content/150/3/383

https://phys.org/news/2018-05-quantum-effects-photosynthesis.html

https://www.quantamagazine.org/a-new-spin-on-the-quantum-brain-20161102/

https://en.wikipedia.org/wiki/Quantum_biology

https://www.lindau-nobel.org/what-is-quantum-biology/