Photons are oddballs.
When they’re not busy being waves,
它们没有质量 以光速传播 因为
they’re massless particles that can travel at light speed because,
well, that’s what they are, little packets of light.
For decades it was also thought
photons didn’t interact with each other at all,
but recently researchers have discovered how to bind photons together
as though they were molecules.
With flashlights, unlike ghostbusting equipment,
you can cross the streams all you want.
Photons don’t bounce off each other
or cause every molecule in your body to explode
because photons don’t much care for one another.
Unless, that is,
they’re fired through a ultracold cloud of rubidium atoms.
When scientists from Harvard and MIT
fired a weak laser through a rubidium cloud,
they observed photons coming out the other side in pairs and triples.
Not only that, but they could tell
from how much the photons were oscillating
that they weren’t just bunched up together coming out of the cloud —
they were bonded, like molecules.
They could even tell how strong the bond was based on their oscillation frequencies!
But before we get too ahead of ourselves, I should tell you
that not all of this is new news.
Back in 2013, scientists fired a blue laser
at ultracold rubidium gas and observed the
photons forming pairs when they came out theother side.
What’s new THIS time are that the photonsformed the trios.
Scientists weren’t sure
if it was even possible to form groups of three interacting photons.
Turns out it’s not only possible,
but three photons interact even more strongly than pairs of photons.
To explain how this happens,
researchers believe that as the photons travel through the rubidium cloud,
they’re briefly captured
by the atoms to form an atom-photon hybrid called a Rydberg polariton.
The photon travels from atom to atom doing this,
and if two polaritons come across one another,
the photons can mingle thanks totheir atomic partner.
They become entangled, and when they reach the edge
of the gas cloud the atoms stay behind
while the photons stick together.
It’s like two shy people being
introduced to each other by their more outgoing friends at a party.
They’d never approach each other on their own,
but once they meet they really hit it
they’re even open to
adding a third person to the mix. Ok,
I’m going to abandon this metaphor
before I get in trouble.
These new photonic molecules have interesting properties,
like taking on a tiny amount of mass,
which is crazy when you remember photons by themselves are massless.
They also travel about 100,000 times slower than normal,
so you know, around a sluggish
10,000 kilometers per hour.
What we can DO with these photon molecules remains to be seen.
They could make it possible for computer logic gates to use light,
instead of inefficiently
converting light to electrical impulses and back again like some do now.
Or they could be used in quantum computing to carry information,
thanks to their entangled state.
OR if adding more photons to the mix makes them interact more strongly,
maybe it’s possible to make entire crystals out of light!
Time and more research will tell, so moreresearch is needed.
Be the light of our life, take a sec, andsubscribe.
Speaking of quantum craziness, did you hear scientists teleported stuff to SPACE?
A handsome devil talks about it here.
While photons in the visible spectrum usually won’t interact,
very high energy photons
have a higher probability of bouncing off one another,
the process called gamma-gamma scattering.
Thanks for absorbing our photons into youreyeballs.