Speaker 1: Okay, I want you to try something with me, just
for a second. We're gonna do a little visualization exercise.
I want you to imagine you are floating in the
absolute deepest, darkest void of empty space. Okay, I'm talking
light years away from the nearest star. There are no planets,
no dust, no gas. It's just pure, unadulterated nothingness.
Speaker 2: The perfect laboratory. Yeah, the physicists dream, No friction, no noise,
just a perfect vacuum.
Speaker 1: Exactly. It's a blank canvas. Now, in this total emptiness,
you fire a single electron, just one tiny little particle
zipping through the dark. Right, according to everything you and
I were taught in high school physics, and let's be honest,
most of what you learn in university too, what should
happen to that electron?
Speaker 2: Well, the classical intuition here is rock solid. It goes
all the way back to Isaac.
Speaker 1: Newton, the man himself.
Speaker 2: The rule is, if there are no forces acting on
an object, and by that I mean no electric fields
pushing it, no magnetic fields twisting gravity pulling on it,
it has to just continue in a straight line, in
a straight line at a constant speed. It's the law
of inertia.
Speaker 1: Newton's first law. An object in motion stays in motion
unless an external force gets involved. It's like the golden
rule of physics, no force, no change.
Speaker 2: Precisely, if there's nothing touching it and nothing pulling it
from a distance, Yeah, it cannot possibly change its path.
It's it's impossible.
Speaker 1: Okay, So hold that word impossible in your head, because
what if I told you that I have a device.
It's a little metal box, and it's completely shielded, locked down,
and it's separated from that electron by that same empty space.
This device creates zero force field where the electron is flying.
The magnetic field where the electron is is strictly zero.
Speaker 2: So by definition no force, the rule.
Speaker 1: Hold no force. But if I flip a switch on
that box a box, remember the electron, ever touches a
box that isn't pushing or pulling it in any way,
we can measure. I can still change how that electron behaves.
Speaker 2: What do you mean change?
Speaker 1: I can make it shift its path.
Speaker 2: That sounds telepathy or you know, magic.
Speaker 1: It sounds like a glitch in the simulation, but it
isn't magic. It is real. It's verifiable physics. It's called
the Haranov Bohm effect, and when it was first proposed,
it didn't just confuse people, it split the physics community
right down the middle.
Speaker 2: Oh, it really did, because it forces us to ask this,
this really terrifying question. We spent our whole lives learning
that force fields, electric fields, magnetic fields, gravity, those are
the real things.
Speaker 1: Yeah, they're what run the universe.
Speaker 2: But this phenomenon suggests that maybe the force field is
just a shadow. Maybe there's something deeper, something hidden in
the mathematics that we all thought was just a trick
that is actually running the show.
Speaker 1: So are we looking at the puppet or are we
looking at the strings?
Speaker 2: That is exactly the question.
Speaker 1: Welcome to Thrilling Threads. I'm your host, and I have
to say, looking through the source material we've pulled for today,
including our really fascinating transcript and some pretty heavy papers
from the nineteen fifties, I felt a little bit betrayed
by my physics teacher atrade.
Speaker 2: That's a strong word.
Speaker 1: Well, I mean think about it. We spend years drawing
force diagrams, all those little arrows pointing this way in
that way, and now we're finding out that that whole
system might just be secondary.
Speaker 2: I get it. It's like finding out the alphabet you
learned is just a suggestion exactly.
Speaker 1: So today we are pulling out that one little loose
thread in the fabric of reality, and we are just
going to keep unraveling it until we see what lies beneath.
Speaker 2: And I'm ready. We are going on a journey today
that you know. It starts with something as simple as
planetary orbits and ends with the fundamental question of what
real even means.
Speaker 1: I love this topic because it takes something that sounds
so dry on the surface, you know, textbook definitions of
potentials and scalers, and it turns it into this psychological thriller.
We've got mathematical cheaters, we've got exiled physicists literally on
the run from the government, and an experiment that broke
all the rules.
Speaker 2: And what's so fascinating to me is that this story
doesn't even start with quantum mechanics. It starts with a failure,
a massive, centuries long failure to solve a very specific
math problem.
Speaker 1: Okay, let's unpack that. We're going back to the og
Isaac Newton.
Speaker 2: The man who wrote the rules. When Newton figured out gravity,
he solved what we now call the two body problem
almost trivially. If you have the Earth in the Sun,
he could calculate their orbits perfectly. The math is beautiful,
it's elegant. You draw a line between them, calculate the force,
and boom you're done.
Speaker 1: Two is company, Two is easy.
Speaker 2: But three, three is a crowd. As soon as Newton
added a third body, say you add the Moon to
the Earth's sun system, where you add Jupiter tugging on
the Earth, the math just completely fell apart.
Speaker 1: This is the famous three body problem. And I've always
wondered why is it so hard? I mean, if you
can calculate the force from the Sun, and you can
calculate the force from Jupiter, why can't you just add
them up?
Speaker 2: You can, but it's an absolute nightmare. And the reason,
the entire reason, comes down to one word. Vectors varrows.
Exactly in Newton's world forces our vectors. They have a magnitude,
so how strong is the pole? And crucially, they have
a direction.
Speaker 1: Where's a pulling like an arrow, a little arrow pointing
from the Earth to the Sun.
Speaker 2: Right now, imagine three bodies all moving in every single
split second, their positions change, which means the angles between
them change, which means the direction of all the arrows changes.
Speaker 1: So you're trying to track three different arrows that are
all spinning and growing and shrinking at the same time, and.
Speaker 2: They all affect each other. If body A moves, that
changes its poll on body B. So body B moves,
which changes its pull on body C, which then changes
its pullback on body A. It's a feedback loop of
pure chaos. It's a hair ball, it's a computational catastrophe.
For one hundred years, the smartest people on the planet,
we're talking at Eilerdllen Bear, the absolute heavy hitters of mathematics.
They all tried to solve the three body problem using
force vectors, and every single one of them hit a
brick wall.
Speaker 1: Enter the hero of our first act, Luis Lagrange. It's
the seventeen seventies, and he looks at this, this spaghetti
of arrows, this mess of vectors, and he just decides
to throw the whole approach out.
Speaker 2: Lagrange had this incredible insight. He realized that working with
direction was the core of the problem. Direction means geometry,
it means angles, it means trigonometry. It is messy. He
wanted to find a way to strip direction out of
the equation entirely.
Speaker 1: So he invents a new character for our story, the potential.
Speaker 2: Right, And to really get your head around the potential,
you have to stop thinking about space as this empty
void and start thinking of it as a landscape.
Speaker 1: I love this analogy. Let's really break this down.
Speaker 2: Okay, imagine a hilly terrain. You're looking at a topographical map.
At every single point on that map, there's a specific
height and altitude. Maybe you're a five hundred meters, maybe
you're at two hundred meters.
Speaker 1: Okay, So that height is just one number. It doesn't
point north or south or upper down. It's just five.
Speaker 2: Hundred precisely, it's a scaler. A scaler is just a
magnitude of no direction. Temperature is a scaler, mass is
a scaler, Altitude is scaler. Legrange's idea was to assign
a height number a gravitational potential to every single point
in space around a star.
Speaker 1: So instead of drawing an arrow pointing at the star,
you just draw a map where the star sits at
the bottom of a really deep valley.
Speaker 2: Yes, a gravity Well, now here's the stroke of genius.
If you place a marble on the side of a hill,
which way does it roll?
Speaker 1: It rolls down the slope, the steepest way down right.
Speaker 2: The slope tells you the direction. The slope is the force.
The slope is the vector.
Speaker 1: I see it now. So if you just know the
shape of the hill the potential, you automatically know the
force on anything you put there. You just look at
which way is down.
Speaker 2: You've got it. And here is why this changed everything.
Adding scalers is incredibly easy. If you have three stars,
you don't have to do all this complicated trigonometry with arrows.
You just take the altitude map of Star A and
you literally just add it to the map of Star
B and add that to the map of Star C.
Speaker 1: You're just adding numbers five plus ten plus two.
Speaker 2: You're just stacking the landscapes on top of each other
to get one final master landscape. And once you have
that master landscape, you just look at the slope at
any point to see how things most.
Speaker 1: It is. Honestly, it feels like it as sheet code for physics.
Speaker 2: It really felt like one to them too. It completely
revolutionized physics. Now, it didn't solve the three body problem
in the sense of finding one simple formula that was
actually proven to be impossible later on, but it gave
physics a whole new language. It turned a really hard
geometry problem into a much easier accounting problem.
Speaker 1: And this is what led to the famous Lagrangian, which
sounds like a spaceship from Star Trek, but it's actually
an equation.
Speaker 2: It is the absolute foundation of all modern physics. One
dollar isles TV Molner. It's the kinetic energy minus the
potential energy. Lagrune showed that the universe is, in a
sense fundamentally lazy. It always tries to minimize this quantity
over time.
Speaker 1: So you just plug the energies into this other thing,
the Eiler LaGrone equation.
Speaker 2: And you get the answer or for how things move. Yeah,
you can do it without ever drawing a single force.
Speaker 1: Errow the sorts of material we looked at had this
great line it said, this method allows you to get
the right answer without being a good physicist, meaning you
don't need that deep intuitive sense of vectors and forces.
You just plug in the numbers, you turn the crank,
and outcomes of truth.
Speaker 2: It democratized the math in a way, but it also
shifted the entire philosophical focus of physics. Suddenly energy and
potential became the primary tools, not force. And it works
so well for gravity that they immediately started trying to
apply it to other things.
Speaker 1: Right, like electricity, because electricity is pretty similar. Mass attracts mass,
positive charge attracts negative charge. So this guy, Simeon Dennis Poisson,
great name, by the way, excellent name, he applies this
whole hill and valley map idea to electric fields.
Speaker 2: Yeah, and it worked perfectly with one little twist. Gravity
only attracts, so its potential map is always a pit.
Electricity can attract and repel, so you get hills for
positive charges and pits for negative charges. But the math,
the core idea. It held up beautifully.
Speaker 1: Until they hit the boss fight. Ah. Yes, magnetism.
Speaker 2: Magnetism the unruly child of classical physics, the thing that
ruins everyone's perfectly elegant theories.
Speaker 1: So why what makes a magnet so different from a
star or a charged particle.
Speaker 2: Think about the shape of the field itself. With gravity
or electricity, the force lines radiate out from a center
or in towards a center. They're like spikes on a
sea ar chin, right.
Speaker 1: They start somewhere and they end somewhere exactly.
Speaker 2: But magnetic field lines are different. They're loops. If you
look at a simple bar magnet, the field lines come
out of the north pole, they loop around through space.
They go into the south pole, and this is the
critical part. They continue inside the magnet to come back
to the north pole. They form a closed loop. They
have no beginning and no end.
Speaker 1: So you can't make an altitude map out of that.
A hill has to have a peak, the highest point.
You can't have a hill that just goes up forever
in a circle. It's like an mcsher staircase.
Speaker 2: You absolutely can't galer potential. That simple number map just
doesn't work from agnotism because there's no highest point or
lowest point to anchor it. So in the eighteen forties,
this genius William Thompson, who later became Lord Kelvin, he
had to invent a whole new kind of tool. He
introduced something called the magnetic.
Speaker 1: Vector potential, usually written as just the letter A the
mystery character the mystery character.
Speaker 2: And to make a work he had to use a
mathematical operation called the curl.
Speaker 1: Okay, we need to spend a minute on the curl.
Because this is where the visualization gets really cool. The
source we looked at uses a paddle wheel analogy, which
I think is perfect.
Speaker 2: It's the best way to think about it. Imagine the
magnetic potential isn't a landscape of hills, but a river.
It's a slowing current of.
Speaker 1: Water, Okay, a swirling river.
Speaker 2: Now imagine you drop a tiny microscopic tattle wheel into
that water. If the current is moving at the exact
same speed everywhere, the paddle wheel will just float downstream.
Speaker 1: It won't spin at all, right, it just gets care along.
Speaker 2: But what if the current is moving faster on the
left side of the paddle wheel than it is on
the right side.
Speaker 1: Well, the fast water on the left is going to
push that side harder, so the whole wheel will start
to spin.
Speaker 2: Spin. That is the curl. Thompson defined the magnetic field,
the thing we can actually measure with the compass, the
real force as the curl of this underlying potential.
Speaker 1: Okay, so there's a hierarchy here at the bottom. We
have this invisible flowing water the potential. If that water
swirls or changes speed and just the right way, you
get a curl and that curl is the magnetic field.
Speaker 2: That's the mathematical relationship. So in a very real sense,
the potential is the parent and the field is the child.
It's derived from the potential.
Speaker 1: And this is the huge plot twist that I think
set physics on the wrong path for one hundred years.
The physicists of the day didn't believe the parent was real.
Speaker 2: No, they didn't. They decided that the water the potential
was fake, fake.
Speaker 1: As in like imaginary.
Speaker 2: Just a math abstract was the polite word. They used
a book keeping cool, a mathematical scratchbad. They came to
believe that only the spin of the paddle wheel the
field was physically real.
Speaker 1: But why if the math works and it gives you
the right answer, why would you call it fake.
Speaker 2: It all came down to a problem called gauge invariants.
This is kind of the villain of our story in
a way.
Speaker 1: Let's go back to the altitude map to explain this
one perfect.
Speaker 2: Okay, you're standing on a hill. Let's say your GPS
says you're at an altitude of one thousand meters. The
slope is steep, so gravity is pulling you down.
Speaker 1: Got it?
Speaker 2: Now, imagine I have some kind of cosmic being. I
snapped my fingers, and I lift the entire continent, the oceans,
the mountains, the valleys, everything up by ten thousand meters.
Speaker 1: Okay, so I'm way higher up now. My GTS reads
eleven thousand meters, right.
Speaker 2: But has the slope of the hill you're standing on
changed it all?
Speaker 1: No, the steepness is exactly the same.
Speaker 2: So the force of gravity pulling you down that hill
is exactly the same. The physics of how you would
tumble down that hill hasn't changed one single bit, right.
Speaker 1: Okay.
Speaker 2: This means I can change the absolute value of the
potential the altitude arbitrarily. I can add ten, I could
add a million, I can subtract five billion. As long
as I do it everywhere equally, the physical result the
force stays exactly the same.
Speaker 1: I see. So the specific number one thousand meters doesn't
actually matter. Only the difference in height from one point
to another matters exactly.
Speaker 2: And the physicists of the nineteenth century look at that,
and they said, hey, wait a minute. If I can
change this number to whatever I want and the universe
doesn't care, then that number itself can't be real.
Speaker 1: It's subjective. It's not a fundamental property of reality.
Speaker 2: It's redundant. They concluded that the potential was just a
mathematical phantom, a convenient way to calculate the slope. But
the slip, the field, that was the only thing that
actually existed, because the slope is unique. You can't change
the slope without changing the physics.
Speaker 1: So for basically one hundred years, the dogma was set
in stone. Feels are real, Potentials are just math tricks.
Speaker 2: Case closed, don't ask any more questions, just do the
calculations and move on.
Speaker 1: And that consensus held strong for decades until a couple
of real outcasts decided to poke the bear, or maybe
poke the solinoise.
Speaker 2: This is where we get to the human drama of
the episode, and we have to talk about David Boem.
Speaker 1: This guy's origin story is just wild. You'd think a
person who's about to rewrite the laws of physics would
be sitting in some comfy tenured chair at Harvard or something.
But Boem was basically on the run.
Speaker 2: He really was. So let's set the scene. It's the
nineteen forties, We're at Berkeley. David Boehm, is this incredibly
brilliant PhD student, and his advisor is Jay Robert.
Speaker 1: Oppenheimer, the father of the atomic bomb.
Speaker 2: The very same Boehm was working on calculations that were,
it turns out, actually critical to the Manhattan Project, specifically
about how protons scatter. But there was a snag, a
big one. General Leslie Groves, the military head of the
Manhattan Project, was not a fan of Boem. He ran
a background check and found that the Boehm had dabbled
a bit.
Speaker 1: He joined a communist group he.
Speaker 2: Had, and by all accounts, it was mostly out of
boredom and a desire for intellectual debate. He actually quit
the group because he found the meetings dull and the
people too dogmatic. But in the nineteen forties, just having
had the membership card was enough.
Speaker 1: So Groves blocks a security.
Speaker 2: Clearance, which leads to this absolutely absurd situation. Boehm's own
PhD thesis, the work that he wrote, was classified top
secret because it was useful for the bomb. Boem himself
was banned from reading his own thesis.
Speaker 1: That is kofka esque. I mean, you can't make that up.
Speaker 2: Oppenheimer had to go to the university administration and personally
certified that Boehm was a brilliant physicist, so he could
graduate without even defending his thesis because he wasn't legally
allowed to discuss it.
Speaker 1: And the story doesn't even end there. The war ends,
the Cold War starts, and McCarthyism sweeps across the United States.
Speaker 2: The Red Scare ye the House on American Activities Committee
drags Boem in to testify against his friends and colleagues.
He pleads the Fifth Amendment refue using to name names.
Speaker 1: Which was an incredibly brave thing to do back then.
Speaker 2: It was career suicide. Princeton, where he was working at
the time, suspended him and then fired him. He was
effectively blacklisted from American academia.
Speaker 1: And Oppenheimer, who was powerful but was also under a
lot of suspicion himself, basically told Boehm, you need to
leave the country before they completely crush you.
Speaker 2: So Bom goes into exile. He moves to Brazil, then
to Israel, and finally he lands a position in Bristol
in the UK.
Speaker 1: And I think this context is just so important. Boehm
was a true outsider. He had been schewed up and
spit out by the establishment and when you're an outsider,
you're just much less likely to blindly follow the establishment's
rules about physics.
Speaker 2: Absolutely, he had nothing left to lose by questioning the fundamentals.
He was willing to look at the foundations of quantum
mechanics and say, you know what, this doesn't really make sense.
Speaker 1: So in Bristol he teams up with this brilliant grad
student named Yaki Aharanov. And Ahranov isn't trying to solve
some specific engineering problem. He's just he's just poking at
the Schrodinger equation.
Speaker 2: The holy grail of quantum mechanics, the central equation.
Speaker 1: And he notices something that everyone else had just sort
of ignored.
Speaker 2: He notices that the Schrodinger equation, the fundamental formula for
how particles behave as waves, is written using potentials, not fields.
It explicitly usestel fee for the electric potential and other
for the magnetic potential.
Speaker 1: Now, the standard textbook answer for decades had been so what,
it's just written that way for convenience. It's that math
trick again.
Speaker 2: But Aharnov argued, and this is the absolute key insight
that you cannot just swamp the potential for the field
in that equation without fundamentally breaking it.
Speaker 1: Why not?
Speaker 2: It has to do with integration. Let's do a quick,
painless calculus for refresher. If I have a function, say
the field, and I want to get back to the
potential I have integrated and the source we've reviewed use
a great example. If I have the expression ten biole
of dollars and I tell you to integrate it, what
do you get?
Speaker 1: You get five by two two dollars plus C plus C.
Speaker 2: Yeah, you always get plus a constant, that.
Speaker 1: Pesky little constant of integration.
Speaker 2: In classical physics. That C is the arbitrary number. It's
the sea level. It doesn't matter. It watches out. But
Harnoff looked at the quantum math and realized, wait a minute,
in this equation, the sea isn't just disappearing, it's doing something.
Speaker 1: He suspected that the potential contained information that the field
had literally thrown away in the process of being calculated.
Speaker 2: Precisely, he realized that if you try to rewrite quantum
mechanics using only the fields E and B, the equation
becomes a horrible, non local mess. It's hideous. But if
you use the potentials, you'll owneio. It's simple and elegant.
Speaker 1: So he proposes this radical idea. What if the electron
isn't reading the field at all, What if the electron
is directly reading the potential.
Speaker 2: This is a massive paradigm shift. He's basically saying the
ghost in the math, the potential is the real actor,
and the force we measure the field is just a
derivative side effect.
Speaker 1: But extraordinary claims require extraordinary proof. They couldn't just argue
about the math. They had to design an experiment, and
this is.
Speaker 2: Where the pure genius of the Aharanov bone paper from
nineteen fifty nine comes in. They designed an experiment that
was effectively a perfect trap for the old force field theory.
Speaker 1: They needed to create a situation where the magnetic field
is absolutely zero, but the potential is not zero, because.
Speaker 2: If the electron reacts in that zone, if it changes
its behavior, then the potential has to be real. Case closed.
Speaker 1: How how in the world do you build a box
of nothing that is simultaneously full of something. You use
a solenoid, a simple coil of wire.
Speaker 2: A simple coil of wire, think of a spring, a
tightly wound spiral of copper. When you run an electric
current through it, It creates a magnetic field basic electromagnetism
one on one, but the geometry is very special. The
magnetic field is trapped inside the coil. It runs straight
down the middle of the.
Speaker 1: Tube, like water flowing through a pipe.
Speaker 2: Exactly, but outside the coil, if the solenoid is long enough,
the magnetic field is effectively zero.
Speaker 1: So outside the pipe there is no magnetic force. A
compass held out there wouldn't spin.
Speaker 2: Correct, the magnetic field B equals zero. However, remember the curl.
Remember our little.
Speaker 1: Paddle wheels swirling water.
Speaker 2: The math says that even though the slope the field
is zero outside the coil, the underlying potential is still
swirling around the outside of that coil.
Speaker 1: Wait, let me get this straight. The actual force is
trapped inside the pipe, but the ghost water the potential
is swirling around the exterior of the pipe.
Speaker 2: Yes, it's like a whirlpool surrounding a perfectly calm island.
The potential gets weaker as you move further away, but
it is definitely non negotiably there.
Speaker 1: So here's the plan they came up with. You take
a beam of electrons, You use a splitter to send
them down two separate paths. Path one goes over the
top of the solenoid. Path two goes under the bottom.
Speaker 2: And this is the crucial part. Neither path ever touches
or enters the solenoid itself. They travel entirely through that
region where the magnetic field is zero.
Speaker 1: They are flying through the void. No force touches them.
Speaker 2: According to Newton, and according to all of classical physics,
absolutely nothing should happen to them. They should behave exactly
as if the solenode wasn't even there.
Speaker 1: But Boem and a. Harnoff predicted something very different.
Speaker 2: They predicted that the electrons would feel the potential.
Speaker 1: But how how can it feel something if there's no.
Speaker 2: Force through the phase of their wave function. You have
to remember in quantum mechanics, an electron isn't just a dot,
it's a wave. It oscillates, It goes up.
Speaker 1: And down like a little clock ticking.
Speaker 2: That's a great way to put it. Think of it
like a clock on the back of each electron, ticking
at a very specific frequency. Now, on the top path,
the electron is moving in the same direction as the
swirling potential.
Speaker 1: It's going with the flow of the ghost water.
Speaker 2: And that interaction the potential acting on the wave actually
changes the speed of the ticking. It advances the clo
it shifts the phase. And on the bottom path, the
electron is moving against the swirling potential.
Speaker 1: It's going upstream, so it's clock ticks at a different speed.
It gets delayed exactly.
Speaker 2: So when these two electrons from the top path and
the bottom path meet up on the other side of
the solenoid and recombine, their clocks are out of sinc
Their waves are out of phase.
Speaker 1: And when waves are out of phase, you get an
interference pattern.
Speaker 2: The peaks don't line up with the peaks anymore, the
troughs don't line up with the troughs. Everything shifts. This
creates a visible, measurable shift in the interference pattern the
bright and dark stripes on the detector screen.
Speaker 1: So the final prediction is this, I flip a switch,
turning on the solenoid. The magnetic field outside remains zero.
No force ever touches the electrons, but the interference pattern
on the screen jumps to the side. The electrons know
the magnet is on.
Speaker 2: That just wasn't says to happen. It's action without a
force it's spooky.
Speaker 1: So the reaction from the physics community at the time was,
let's just say skeptical.
Speaker 2: Skeptical as being polite. Neil's Boorr, the godfather of quantum mechanics,
the high priests of the Copenhagen interpretation, he hated it.
He absolutely could not accept that a particle could be
affected without a local force. He spent weeks trying to
find a flaw in their logic and couldn't.
Speaker 1: But Richard Feineman Fineman is always my favorite character in
the story of physics. What did he think?
Speaker 2: Fineman loved it. He looked at it, and his reaction
was basically, well, of course, it's obvious, scrange. No one
thought of it before. He saw immediately that the mathematics
of his own path integal formulation demanded it.
Speaker 1: And there was another one, Victor Weiskopf, another giant of
the field, who had that great quote, Oh yeah, he said.
Speaker 2: My first reaction, it's wrong. My second reaction, it's obvious.
Speaker 1: And that's the mark of a real paradigm shift, isn't it. It
goes from that's impossible and you're crazy to well, of course,
how did we not see that?
Speaker 2: It completely reframes the problem. But you know, a theory
on paper is just talk. Someone had to actually build
the damn.
Speaker 1: Thing, and this was incredibly difficult to do in practice.
The first attempt was in nineteen sixty by a physicist
named Robert Chambers.
Speaker 2: And his biggest problem was the infinite solenoid assumption. Right,
you can't just go to the store and buy an
infinitely long wire.
Speaker 1: No, and real solenoids have ends, and magnetic fields leak
out of the ends of the solenoid. They create what's
called a fringe field.
Speaker 2: So Chambers runs the experiment and he sees the shift.
The interference pattern moves just like they predicted.
Speaker 1: But the skeptics immediately pounce. They said, Aha, see your
solenoid isn't infinite. There are leakage fields. The electron isn't
touching some magical ghost potential. It's touching a tiny stray
magnetic field leaking from the top and bottom. Your experiment is.
Speaker 2: Just sloppy, and it's a valid critique. To prove the
effect is real, you have to be absolutely one hundred
percent certain that there is zero magnetic field touching the electron.
If there's even a tiny bit the whole potential is real,
argument falls apart.
Speaker 1: It took twenty six years to get the definitive answer
nineteen eighty six, a kiratonoma at Hitashi in Japan.
Speaker 2: Totamore was a true experimental artist, a perfectionist. He was
not going to leave any room for doubt.
Speaker 1: He realized that the long straight wire approach was always
going to be flawed, so he changed the geometry. He
used a toroid, the donut magnetic donut.
Speaker 2: With a donut shape, the magnetic field can just go
round and around in a perfect circle inside the dough.
It never has to leave the material. It has no ends,
so there's nothing to leak from.
Speaker 1: That's brilliant. But he didn't even stop there. He wanted
to be paranoid. He wanted to be absolutely sure nothing
could possibly.
Speaker 2: Leak out, So he wrapped the entire magnetic donut in
a layer of niobium.
Speaker 1: And naobium is a superconductor.
Speaker 2: It is and superconductors have this amazing property called the
Meisner effect. They actively expel magnetic fields. They're the ultimate
magnetic shield. By wrapping his magnet in a superconducting layer,
he physically guaranteed that the magnetic field outside that donut.
Speaker 1: Was zero, not almost zero, not close to zero.
Speaker 2: Zero point zero. And then he used a new technology
called holographic electron microscopy to actually visualize the wavefronts of
the electrons. This is bleeding edge stuff.
Speaker 1: So let's just recap the setup. You have an electron beam.
It's aimed at a tiny, perfectly shielded magnetic donut. The
beam is set to go right through the hole of
the donut. The field in the hole is zero. The potential, however,
is swirling.
Speaker 2: He turned on the current and he looked at the hologram.
Speaker 1: What did he see?
Speaker 2: The phase shifted perfectly. The peaks of the electron waves
lined up with the drops, exactly as a Hornoff and
Boom had predicted nearly thirty years earlier.
Speaker 1: So it's real. The ghost is real, The.
Speaker 2: Ghost is real. The potential, that thing that physicists for
a century had called a bookkeeping trick and abstract scratch
pad number, actually reached out across empty space and touched
the electron.
Speaker 1: This is the part where my brain just starts to melt,
because now we have to interpret this. What does this
actually mean about the nature of reality?
Speaker 2: It means we have to choose between two maybe three,
very uncomfortable.
Speaker 1: Option Eh, lay the mummy, what's option one?
Speaker 2: Option one? Potential are real? This is the view that
Bowman feinement generally lean towards team potential team potential. This
view says we were wrong for two hundred years. The
field the force is not the fundamental layer of reality.
The potential is the fundamental layer of reality. The universe
is literally made of these scaler and vector values that
are assigned to every single point in space.
Speaker 1: We're all just navigating an invisible landscape of numbers that
dictates how we move.
Speaker 2: Yes, and the force that we feel is just what
happens when that landscape changes shape. As Feinemann wrote in
his lectures, A is as real as B realer, whatever
that means.
Speaker 1: But wait, what about the gauge invariance problem, the whole
C level issue. If I can add a thousand to
the potential everywhere and nothing changes, doesn't that still prove
its arbitrary and not real?
Speaker 2: Ah? This is the really subtle and beautiful part. The
Aronoff Bom effect relies on the electron taking a loop,
it splits and then comes back together. Okay, when you
do the mathematics, of an integral around a c closed loop.
The arbitrary constants that plus C they cancel out. If
I raise the sea level by one thousand meters, I'm
raising it for both the top path and the bottom path,
so the difference in the altitude between the two paths
stays exactly the same.
Speaker 1: So the absolute value of the potential might be arbitrary,
but the topology, the way it changes as you go
around a loop that's absolute and physically real exactly.
Speaker 2: The loop intergral is gauge invariant, the math is solid.
The loop makes the potential real.
Speaker 1: Okay, I think I can live with that. Invisible landscapes.
What's option two?
Speaker 2: Option two? Non locality. This is actually where aronoff himself.
Eventually landity changed his mind over the years.
Speaker 1: Non locality. That's the spooky action at a distance. Stuff.
Speaker 2: That's the one. This view says, no, no, No. Potentials are
still just math tools. The fields are the only real things.
Speaker 1: But but the field was zero where the electron was exactly.
Speaker 2: So if the field is the only real thing and
the field is trapped inside the doughnut, then the field
must be effected in the electron from a distance.
Speaker 1: So it's telekinesis the magnetic field inside the donut is
pushing the electron outside the donut without ever making contact,
without any intermediary.
Speaker 2: Yes, and this just shatters the golden rule of Einsteinian physics,
which is locality, the idea that things can only affect
their immediate surroundings. If option two is right, then the
universe is fundamentally interconnected in a way that allows for instantaneous,
non local.
Speaker 1: Influence That is deeply unsettling.
Speaker 2: It upsets the entire cause and effect structure that we
rely on in classical physics.
Speaker 1: So you have to pick your poison. Either the universe
is run by invisible math numbers that we can't directly see,
which is team potential, or things can touch you from
across the room without anything traveling between you, which is
team nonlocal.
Speaker 2: There is sort of a third way, a kind of
mill ground. We could call it option three. The path
integral view.
Speaker 1: The Casper the friendly ghost speculation.
Speaker 2: Is Feinnman's view of quantum mechanics. In his path integral formulation,
a particle doesn't take just one path from A to B.
It takes every possible path simultaneously.
Speaker 1: The multiverse of paths.
Speaker 2: Right so even though the main path for the electron
goes through the whole of the doughnut where the field
is zero, there are other less probable ghost paths that
might actually tunnel through the magnet itself, touch the field,
and then rejoin the main group.
Speaker 1: So the electron did touch the field, it's just the
version of the electron that did that wasn't the main
one we were tracking.
Speaker 2: In a manner of speaking, it's like the particle sends
out feelers along all paths, samples the entire environment brings
that information back, and that's what shifts the phase. It
saves locality, but it requires you to accept that particles
are kind of doing everything everywhere all at once.
Speaker 1: I think I need to sit down for a minute.
Speaker 2: It's heavy stuff, it really is.
Speaker 1: And just to twist the knife one last time. This
isn't just some weird quirk of electricity, is it.
Speaker 2: No, it's not. For a long time we thought maybe
this was just a weird thing about electromagnetism, But very
recently twenty twenty two, a team of researchers at Stanford
finally managed to test this with gravity.
Speaker 1: With gravity the original force.
Speaker 2: They use something called atomic fountains. They take these ultra
coold rubidium atoms and launch them up in a vacuum.
Speaker 1: Tube, and they split them somehow.
Speaker 2: They use lasers to split the wave function of the atom,
so one part of the atom's wave goes slightly higher
than the other part.
Speaker 1: So they were at two different altitudes on the gravitational
potential hill exactly.
Speaker 2: They were exploring different values of the gravitational potential. Yeah,
and even when they accounted for every other possible effect,
they saw the phase shift.
Speaker 1: So gravity does it too.
Speaker 2: Gravity does it too. It seems this effect, this connection
to the potential, is not a bug. It's a fundamental
feature of our universe.
Speaker 1: Wow, so let's just try to wrap this whole thing up.
We started with Isaac Newton crying over his vector arrows
because the three body problem was too hard.
Speaker 2: Then we invented a math hack called potentials to make
the problem easier.
Speaker 1: We then spent the next two hundred years telling physics students,
by the way, that hack is fake, it's not real,
just use it to pass the test.
Speaker 2: And then, thanks to an exile physicist and his curious student,
we ran in an experiment that proved the hack is
actually the reality.
Speaker 1: There's that old saying the map is not the territory,
But in this case, it's like we found out the
map is the territory.
Speaker 2: Or perhaps we were looking at the map the whole
time and mistakenly calling it the world.
Speaker 1: It really just highlights the danger of dogma and science,
doesn't it. If Bohm hadn't been pushed to the outside,
if he had stayed in the comfortable center of the
physics establishment, maybe he never would have had the guts
to question the rules.
Speaker 2: Sometimes you have to be standing outside the donut to
see what's happening in the hole.
Speaker 1: I love that that's a perfect summary.
Speaker 2: It's a lesson for all of us. Really, just because
a model works, just because you can build bridges and
land on the moon with it, doesn't mean it's the
ultimate truth. Newton's laws got us to the moon, but
they couldn't explain this.
Speaker 1: Electron textbooks are always provisional. So I have to ask
a final question, both to you and to everyone listening.
Where do you stand on this?
Speaker 2: It's the ultimate vote on the nature of reality.
Speaker 1: Are you team potential? Do you like the idea that
we're guided by this invisible landscape, these hidden scaler values
that make up a kind of script for the universe.
Or are you Team non Local. Do you prefer the
spookier idea that the universe is a single, interconnected web
where things can touch each other from a distance across
the void?
Speaker 2: You know, I think I'm gonna have to go with
Team Non Local. I like the idea of that fundamental connectivity.
It's weird, but it feels more holistic.
Speaker 1: See I'm going Team Potential. I like the idea of
a hidden landscape. It feels more grand and architectural.
Speaker 2: Well, we want to hear from you. Leave a comment
wherever you are listening. Let us know your vote, Team
Potential or Team Non Local. Let us know which one
is more unsettling to you.
Speaker 1: Thanks for unspooling these mysteries with us. It has been
a truly mind bending ride. This has been thrilling threads.
Speaker 2: Keep pull into those loose ends. You never know what's
going to unravel.
Speaker 1: We'll see you next time.