Physicists have conducted a famous physics experiment for the first time using antimatter.
Get ready to dive into the quantum world, folks.
We’re goin’ deep.
If you’re new to quantum physics, you may want to watch this video where we cover the
basics.
Essentially, we’ve got two main ways of explaining the universe--one that works with
our idea of gravity, and one that works on the quantum level.
The problem is, they don’t agree with each other.
Experimentalists and theorists are searching for the magic key that could resolve this
paradox for us--what we like to call ‘a theory of everything’.
And some think that the answer lies in a classic physics exercise called the double-slit experiment.
Here’s how it works: you have a sheet with two slits in it.
Behind that, a blank sheet.
You have your source of matter, let’s say...cheese balls.
If you fire the cheese balls through the double slit sheet, you should get two lines of orange
cheese ball dust on that back sheet.
Simple enough.
But let’s say instead of cheese balls we want to fire something that moves in a wave,
like sound.
Instead of getting two slit-like impressions on the back sheet, you get a pattern of several
lines.
That’s because the sound waves, as they’re passing through the slits, bounce off each
other and cancel each other out in what’s called an interference pattern.
But some things are not only a wave, they’re also a particle.
For example, the basic unit of light is the photons--so what would happen if we start
firing individual photons, not as a wave?
Well, if you cover one of those slits, you get what you’d expect--the imprint of those
particles on the back sheet in one line.
They just travel straight through--they’re behaving like the cheese balls, and not like
the wave.
But then--and hold onto your hats here--you uncover both slits, and fire the photons (again,
not as a wave).
You’d expect to see two lines on the back sheet, like with the cheese balls, but NO!
You see an interference pattern, even though the light shouldn’t be behaving as a wave.
It’s almost like the photons know where the other photons are going to end up before
they’ve gotten there, like they’re connected to each other on some level we can’t understand.
Maybe somehow the particle splits itself and travels through both slits at once, interferes
with itself, and then reunites into one particle and that’s what produces the pattern?
Well, if you put a detector by the slits to try observe what’s happening, the particles
stop producing an interference pattern and start behaving like the cheese balls.
Like they KNOW you’re watching.
What?
This mystery--this absolutely bizarre behavior--is widely considered one of the central mysteries
of quantum physics, bringing together what we still don’t know about the wave particle-duality
of matter and the problem of measuring things on the quantum level.
We still don’t really know why observing and measuring a phenomenon may change what’s
happening.
Some scientists think that if we could understand the mechanics behind the double slit experiment,
that knowledge would be the missing piece we need to unify our quantum theories of the
universe with the theory of gravity.
And for the first time ever, we’ve seen that the double slit experiment works for
antimatter too.
Each fundamental particle has a complementary particle that behaves in some kind of opposite
way, like its spin or its charge.
That’s antimatter.
The electron’s antimatter particle is the positron.
The electron is negatively charged, the positron is positively charged.
This new study replicated the double slit experiment using positrons, demonstrating
that antimatter behaves the way matter does in this situation.
Part of the reason no one’s done this before, is because antimatter is pretty hard to get
your hands on.
Now, this paper was just published, and has yet to be peer-reviewed, but aims to be just
the start of this team’s exploration into the nature of antimatter.
Why?
The main goal is to find out how gravity acts on antimatter.
Which is important because some scientists think that gravity may act differently on
antimatter than it does on matter, potentially helping us fill in the gaps between general
relativity and the standard model, getting us one step further to a unified theory of
everything.This may also help us explain why there’s so much more matter in the universe
than antimatter...a question we still don’t know the answer to.
So that would be pretty cool.
Subscribe to Seeker for all your quantum physics needs.
And Fun fact: the double-slit experiment was first performed in 1801!
Thanks for watching.