Tag Archives: Richard Feynman

How to think like a genius with Richard Feynman

Richard Feynman in 1984 in Waltham, Massachusetts. Credit: Tamiko Thiel/Wikipedia.

American quantum physicist Richard Feynman was one of the world’s greatest thinkers. He’s famous for his Nobel Prize-winning work in unraveling quantum mechanics and for his work on the Manhattan Project where he helped design the first atomic bomb — but Feynman not only made his mark as a physics genius but also shined as an educator.

Feynman’s legendary Lectures on Physics are available for free on Caltech’s website, still relevant as ever. But rather than formal lectures, I’d rather focus on sharing some of Feynman’s wisdom — particularly his innovative but practical method for solving huge, challenging problems. Essentially, it’s a blueprint for thinking like a genius — from a genius.

Feynman was a rebel who refused conventional education and groupthink. In other words, he strived for originality and creativity, but never at the expense of accuracy. According to Marvin Minsky at MIT, “When Feynman faces a problem, he’s unusually good at going back to being like a child, ignoring what everyone else thinks… He was so unstuck — if something didn’t work, he’d look at it another way.”

It is thanks to such thinking that Feynman arrived at the counterintuitive results of the Columbia Space Shuttle disaster investigation, in which he had a leading role. Feynman quickly realized that NASA had a disconnect among its engineers and its managers, and he concluded that “For a successful technology, reality must take precedence over public relations, for nature cannot be fooled.”

But keeping a childlike curiosity is only part of the approach. In order to really think like a genius (the kind that is rewarded with a Nobel Prize for fundamental work in quantum electrodynamics) one needs to always have big problems at the back of their minds.

According to MIT professor Gian-Carlo Rota, who is a famous professor in his own right, Richard Feynman was fond of giving the following advice on ‘how to be a genius:’

“You have to keep a dozen of your favorite problems constantly present in your mind, although by and large they will lay in a dormant state. Every time you hear or read a new trick or a new result, test it against each of your 12 problems to see whether it helps. Every once in a while there will be a hit, and people will say: ‘How did he do it? He must be a genius!’,” Rota says.

This is very straightforward but extremely powerful advice. It shows that rather than needing a super high IQ, it is possible to tackle very difficult problems with some foresight and mental hacking. Spotting patterns on some abstract test might score you bragging rights, but ultimately it is the ability to solve problems and make the world a better place that is the mark of a real-life genius.

Heisenberg’s uncertainty principle is more than a mathematical quirk, a handy guiding principle, or the inspiration for some really nerdy t-shirts. It is intrinsic to nature, weaved into the fabric of all matter. Together we take a trip to ZME labs to use some everyday objects to demonstrate how nature tells us “you can’t have it all.”

Certainly Uncertain: What’s Heisenberg’s Uncertainty Principle

At the beginning of the 20th Century, physicists were developing the field of quantum physics, discovering in the process that the rules they had grown comfortable with no longer applied at the smallest scales. For example; the argument about the nature of light — was it particle or wave — that had raged for decades  could be answered only by concluding it is neither but has properties of both. Furthermore, they found that this particle/wave duality applies to matter particles like electrons too.  

German theoretical physicist Werner Heisenberg was about to make his own shocking discovery, he was about to find that nature imposes a fundamental limit on what even the most aspiring physicists could know.

He would formulate this concept into the uncertainty principle.

A portrait of Werner Heisenberg taken in 1933. Ironically the author of the image is unknown (CC by SA)

In 1925, Heisenberg would publish a paper that informed physicists that nature has a way of telling you that you can’t have your cake and eat it too. Something intrinsic and built into the fabric of the very Universe that reminds you that no matter how smart you are, no matter how sophisticated your experimental method, how sensitive your equipment, you can’t ‘know’ everything about a system. An idea that contradicts the principles that classical physics was built upon.

Assuming the name Heisenberg’s uncertainty principle, the Heisenberg uncertainty principle, or simply, the uncertainty principle, the concept would become arguably the second most commonly recognised element of quantum physics, outside of Schrodinger’s eponymous feline. Eventually, this idea would find itself absorbed into pop-culture, making its way to jokes, newspaper strips, t-shirts, and cartoons.

“The uncertainty principle ‘protects’ quantum mechanics,” said legendary physicist Richard Feynman of the utility of Heisenberg’s breakthrough. “Heisenberg recognized that if it were possible to measure both the momentum and the position simultaneously with greater accuracy, quantum mechanics would collapse. So he proposed that must be impossible.”

What is the Uncertainty Principle?

The most generalised version of Heisenberg’s uncertainty principle says that if you measure the momentum of a particle with uncertainty Δp, then you are limited in how precisely you can ‘know’ its position. You can’t know it any more precisely than Δx ≥ ℏ/2Δp, where ℏ (or H-bar) is a value known as the reduced Planck’s constant and is extremely small, a fact that will become important when we ask why macroscopic objects like cars and balls don’t seem to be affected by the uncertainty principle. 

Rearranging the equation above gives the most common version of Heisenberg’s uncertainty principle, and perhaps the most famous equation in physics outside of E=mc^2. This equation tells us that when the uncertainty in position is multiplied by the uncertainty in momentum its value can’t be greater than the reduced Planck’s constant divided by two. 

The equation above also applies to several other variables, most notably energy and time, it can also be adapted to any suitable pairs of operators in a system.

The momentum and position version of the uncertainty principle may well be the most familiar but it is by no means the only version, nor should the other versions be considered less important. In fact, the energy/time variation of the uncertainty principle gives rise to one of the most striking and counter-intuitive elements of reality — the idea that virtual pairs of particles can pop in and out of existence. 

If you consider an infinitesimal isolated area of spacetime observed for a precisely ‘known’ period of time, then the uncertainty principle for energy and time (ΔE Δt = ≥ ℏ/2Δ) says that you can’t precisely know the energy content of that area. Meaning that particles must be popping in and out of existence in that box.

This concept, wittily named ‘nature’s overdraft facility’ by some waggish physicists, is a phenomenon that sounds unlikely, impossible even, but has been experimentally verified. The Heisenberg uncertainty principle limits just how long the Universe will allow itself to go ‘overdrawn’ before the particles annihilate and that energy loan is paid back.

In order to get aspiring-physicists to accept the radical ideas birthed from the uncertainty principle, and that concept that there is a fundamental limit to what can be known about a system — something contrary to classical physics —thus meaning that everything classical physics imparts about the ‘knowability’ of a system is wrong,  a ‘semi-classical’ version was first presented to the scientific community.

We approach it now with some trepidation and the warning that it barely scratches the surface of the uncertainty principle and somewhat downplays how intrinsic it is in nature. 

The Semi-Classical Uncertainty Principle

You’re asked to take part in a quantum physics experiment at the ZME labs. You arrive, are immediately handed a tennis racquet and asked to step into an extremely dark room. Once in there, a voice announces that your task is simply to find the tennis balls in the room with the racquet. 

“Sounds simple enough,” you think. That is until a tennis ball strikes your leg at high-speed. You realise that the tennis balls are being fired into the room at completely random angles. Eventually, after some failing around in the dark, you’re racquet hits a ball. “Got one!” you exclaim. 

“That’s great,” comes the voice over the intercom. “Where is it now?”

Of course, the problem with that crude little analogy is that the very act of ‘measuring’ the ball’s position or momentum, intrinsically changes the state of the system and essentially puts you back at square one. It’s a little like that every time we try to take a quantum mechanical measurement. 

In order to ‘see’ an electron, researchers have to fire photons at it. The problem is that photons carry with them momentum. And as electrons are so small, the wavelengths of the photons have to be of a similar scale. The issue is, the shorter the wavelength, the higher the energy and, in turn, the greater the momentum. 

Thus, bombarding an electron with photons imparts this moment to them, changing the very state of the system. 

The reason that the semiclassic description of the Heisenberg uncertainty principle is that it gives the impression that if there was some incredibly sensitive measuring technique, it could, perhaps, be ‘worked around.’ This isn’t true. No matter how sensitive, this relationship is something that can’t really be avoided. It’s ‘built-in’ to nature. 

To see why this is the case it’s necessary to investigate one of the founding principles of quantum mechanics, the ubiquitousness of waves. 

Wave Certainty Goodbye

You receive a call from ZME labs. “We know the last experiment didn’t go so well, and we really hope the bruises are healing,” says a painfully familiar voice. “Look, we’ve got another test and this one will really demonstrate Heisenberg’s uncertainty principle… no tennis balls.”

You reluctantly agree to attend. 

Upon your arrival, you are handed a skipping rope and asked to wave it up and down rhythmically. The opposite end is held by a nervous-looking lab assistant who you notice is covered in tennis ball sized welts. 

Below is what results from your frantic, yet rhythmically waving. A steady wave shape. But, here comes the voice through the loudspeaker again: “Ok, now tell us, where on the x-axis [which marks position] is the wave?”

As you can see, the wave has no well-defined position, and here is how that is analogous to a particle in quantum mechanics. In the mathematics used to describe a quantum system, the spread of the wave is momentum, the square of the amplitude is the probability of the particle being located in a particular position.

Thus, in the above image what we actually have is a very well-known momentum. And as Heisenberg’s uncertainty principle primes us to believe, we can see that we can say nothing about the position as the wave can’t be said to possess a single position on the x-axis. The square of the amplitude is the same everywhere.

Back to ZME labs. You’ve had just about enough of these cryptic unanswerable questions and bizarre sports-equipment related experiments. So to teach the researchers a lesson, you give the rope one sudden ‘whip’ — Indiana Jones style. 

The wave is suddenly localised, as you can see, the amplitude and the thus the square of the amplitude is zero everywhere but in one spot. A position can be assigned to the wave, but as you can see, there is no spread anymore — the wavefunction is destroyed. 

This is analogous to having exact knowledge of a particle’s location. As the wavefunction spread is destroyed and this was the representation of the particle’s momentum, you suddenly have no knowledge of momentum. 

All this shows that Heisenberg’s uncertainty principle really arises from the fact that matter can be described as waves on the quantum level.

You are on your way out of ZME labs, for what you hope is the final time and nursing serious whiplash in your wrist when the lead researcher hands you a tennis ball. “As a memento,” he says chirpily.

You thank him, but mentally vow to throw it over the tallest wall you can find on the way to your car and home. 

Little do you know, your rage against the ball will reveal how without the phenomena described by Heisenberg’s uncertainty principle  the Universe would be a much colder, and darker place. 

Quantum tunnelling: Quantum balls and tall walls

One of the most remarkable features of the quantum realm is the phenomenon of quantum tunnelling, without which the nuclear fusion processes that power the stars and create the Universe’s heavier elements would not be able to take place. 

Tunnelling allows protons in the core of the sun to overcome mutual repulsion caused by their positive charges, a potential barrier that even under extreme pressure, they do not have the kinetic energy to overcome. This allows the formation of deuterium from hydrogen nuclei and begins the nuclear fusion process in the star’s core which leads to the formation of helium from hydrogen and powers its immense energy output.

You’re thinking about quantum tunnelling on your way to your car when you feel the tennis ball you received as a ‘memento’ and stuffed in your pocket pressing into your thigh. Remembering your promise, you look at the nearest wall, noting that it’s probably higher than you can throw the ball. 

You resolve to give it a few tries anyway. 

You throw the ball a few times, each with exactly the same force against the same resistance provided by gravity and air resistance, realising you can’t give it enough kinetic energy to get it over the top of the wall. In fact, you’re falling considerably short. But, this is a special ball. The researchers at ZME labs have found a way to imbue it with the qualities of a quantum particle. 

On your 47th throw of the quantum ball with the same kinetic energy, the ball approaches its usual limit and simply disappears. You inspect the wall seeing no holes, and you know there is no way the ball could have broke through the wall… then you hear a loud cry from the over the side of the wall scream: “My flowers… Whose ball is this?” You decide discretion is the better part of valour, and flee the scene. 

So, how can Heisenberg’s uncertainty principle be responsible for the ball travelling to the other side of the wall, an area that in physics we would describe as ‘classically forbidden’?

The key is, that as we precisely know this quantum ball’s momentum, we can’t be sure of its position. This means that there is a tiny probability that the ball can be found in a region it should be impossible to reach. 

Below, you can see a simulation of what happens when a particle of certain energy approaches an energy barrier that exceeds its energy. It should be noted here that the ‘wider’ or ‘taller’ the barrier, ie. the greater the energy demand, the less likely a particle is to clear it. 

You can think about tunnelling like this. A particle of energy <E> approaches a barrier of <2E>. Clearly it doesn’t have enough energy to ‘jump’ this barrier. Yet, in quantum physics, we find a small probability that transmission occurs. Obviously, that means that in circumstances where you have a lot of particles, like in the core of a star, the law of large numbers suggests that this kind of rare event still happens a lot.

As you muse on this, you have a worrying thought: “I know the exact momentum of my car. Does that mean I can’t know its position?”

You quicken your step considerably. 

Dude where’s my car? Why Heisenberg’s uncertainty principle doesn’t apply to everyday objects

Heisenberg and Schrödinger get pulled over for speeding. The cop asks Heisenberg: “Do you know how fast you were going?”
Heisenberg replies: “No, but we know exactly where we are!”
The officer looks at him confused and says: “you were going 108 miles per hour!”
Heisenberg throws his arms up and cries: “Great! Now we’re lost!”


We’ve thus far had a little fun describing macroscopic objects like tennis balls and skipping ropes displaying quantum behaviour, so it’s probably an idea to explain why this isn’t something we actually see every day.

The key is the very small value of the reduced Planck’s constant (ℏ). This means that the lower limit in the uncertainty of measuring the position and momentum of large objects is negligible when compared to massive objects like tennis balls, skipping ropes or cars. 

All matter has a de Broglie wave (λdb) but that wave has to be a comparable size to the Planck’s reduced constant for Heisenberg’s uncertainty principle to have a considerable effect. The de Broglie wave of a tennis ball is way too small to be subject to the uncertainty principle in any significant way.

It’s for much the same reason that moving objects don’t diffract around trees. Their de Broglie wave is way too small.

Sorry, you’re not getting off with that speeding ticket so easily. 


Sources and further reading

Griffiths. D. J, ‘Introduction to Quantum Mechanics,’ Cambridge University Press, [2017].

Feynman. R, Leighton. R. B, Sands. M, ‘The Feynman Lectures on Physics. Volume III: Quantum Mechanics,’ California Institute of Technology, [1965].

Bolton. J, Lambourne. R, ‘Wave Mechanics,’ The Open University, [2007].

Credit: YouTube.

Celebrating Richard Feynman’s 100th Birthday

Credit: YouTube.

Credit: YouTube.

On this day one century ago, a brilliant mind was born. Richard Feynman is considered one of the 20th-century’s most accomplished theoretical physicists, along with Albert Einstein and the recently-deceased Stephen Hawking.

Feynman’s most celebrated work is his contribution to quantum theory — especially its electrodynamics, “with deep-plowing consequences for the physics of elementary particles,” which won him the Nobel Prize. He could have won it again, many believed, for his work with Murray Gell-Mann that led to a theory for weak interactions, describing such phenomena as the emission of electrons from radioactive nuclei.

”I won the prize for shoving a great problem under the carpet,” Feynman said disingenuously, ”but in this case there was a moment when I knew how nature worked – it had elegance and beauty,” referring to his later work.

He was also one of the members of the top-secret team of scientists at Los Alamos who would go on to invent the atomic bomb. While there, Feynman would often be up to no good, spending his time cracking safes containing secret papers and leaving mocking notes inside, demanding one dollar for the return of patents.

https://www.youtube.com/watch?time_continue=2&v=4zZbX_9ru9U

In this archival footage from BBC TV, celebrated physicist Richard Feynman explains what fire, magnets, rubber bands (and more) are like at the scale of the jiggling atoms they’re made of. This accessible, enchanting conversation in physics reveals a teeming nano-world that’s just plain fun to imagine.

Like Hawking, Feynman is one of the few scientists who has entered the public’s consciousness thanks to his uncanny personality and charisma. His pioneering Caltech lectures and two autobiographical books gained him celebrity status, earning him the reputation of a quirky physicist whose humor and stage persona rivaled those of TV personalities.

Credit: Public Domain.

Credit: Public Domain.

Despite his many accomplishments, it wasn’t until the 1986 unfortunate accident, the explosion of the space shuttle Challenger, that Feynman came to the attention of millions of Americans. At the time, Feynman was appointed to the Presidential commission investigating the explosion. His presence proved essential to uncovering the root cause of the disaster that claimed the lives of all seven astronauts on board, including high school teacher Christa McAuliffe, and brought NASA’s human spaceflight program to an abrupt but temporary halt.

In honor of one of the most creative and original scientists of modern history, the California Institute of Technology, where Feynman worked for almost four decades until his death in 1988, is hosting a two-day meeting. The “Feynman 100” event will feature some of the world’s leading scientists, and some of Feynman’s closest friends and family, including his sister Joan and his adopted daughter Michelle. Some of the guest stars present at the event include Freeman Dyson, David Gross, Lisa Randall, Sara Seager, Leonard Susskind and Kip Thorne who will “survey the current frontiers of knowledge and share their vision of where science is heading.”

[ALSO SEE] Book review: ‘The Quotable Feynman

Richard Feynman

Richard Feynman’s Lectures on Physics released for free online

Richard Feynman

Photo: Scientific American

Arguably the sexiest man in physics, Richard Feynman is one of the most well known scientific personalities. Along with two other physicists, Feynman was awarded the Nobel Prize in Physics in 1965 “for their fundamental work in quantum electrodynamics, with deep-ploughing consequences for the physics of elementary particles” — specifically for the development of “Feynman diagrams.”

There are many physicists who have made remarkable contributions to science, yet what made Feynman so special was his uncanny ability to communicate his findings and physics in general. Feynman was at times called “The Great Explainer” because of his skill at making complex subjects accessible to students, and while still a professor at Caltech he released his now famous Feynman Lectures on Physics. The three-volume collection has since become the most popular physics text book. Now, the whole collection is available for free, online for your personal consideration.

If you’ve ever been discouraged by physics classes, but would still like to dabble, look no further. Study these notes with care and patience and you’ll be amazed how easy it is to understand physics, be it classical thermodynamics or spooky quantum mechanics. Seriously, you’ll be surprised!

Richard Feynman explains the scientific method in 10 miuntes

Richard Feynman is one of the most known and loved physicists to ever walk the face of the planet. He is known for his research in path integral formulation of quantum mechanics, the theory of quantum electrodynamics, and the physics of the superfluidity of supercooled liquid helium, as well as in particle physics. But perhaps for the most of the world, he is known most for his amazing quality to teach very complicated matters in a simple, attractive way. His charismatic persona inspider many, many people, and personally, I highly recommend this, and any other Feynman books or videos.

Richard-Feynman-007

The symphony of science

I was quite stunned to stumble across this video. As the name says, it’s a… well it’s not quite a symphony, but it’s definitely musical, and you can definitely learn a lot of things, or re-hear them in an unique way, if you already know them. Did I mention it’s featuring Carl Sagan, Richard Feynman, Neil deGrasse Tyson & Bill Nye?

LATER EDIT

This following video was published just a few hours ago and… it’s even better than the first one!