All language subtitles for NOVA.S46E02.Einsteins Quantum Riddle.480p.WEBRip.x264.rmteam

We live in a world

where objects have permanence.

And we see cause, then effect.

But a startling phenomenon
is revealing

that this is not
how the universe works

at the smallest scales of atoms
and tiny particles.

Albert Einstein argued
it couldn't possibly be real.

Einstein was like
a jack-in-the-box;

every day, he'd pop up
with a new challenge.

But after a century of disputes
and discoveries...

The experiment is
just beautiful.

We're using it to create
revolutionary, new technologies.

What we have here is
a quantum playground.

We want to push
these technologies

as far as possible.

It's perhaps the strangest
concept in physics.

We're left with conclusions
that make no sense whatsoever.

Yet it could be what forms
the very fabric of our cosmos.

In the end, we just have
this quantum mechanical world.

There is no space anymore.

It's like being
in "Alice in Wonderland."

Everything is possible.

Could it be real?

It's
"Einstein's Quantum Riddle,"

right now, on "NOVA."

Major funding for "NOVA"
is provided by the following:

Is reality an illusion?

Could something here
mysteriously affect

something there?

A century of discoveries
in physics

reveals a strange,
counterintuitive micro-world

of atoms and tiny particles

that challenges
our intuitive understanding

of the world we see around us.

It's known as quantum mechanics.

This strange theory has
enabled us to develop

the remarkable technologies
of our digital age.

But it makes
a very troubling prediction...

Called quantum entanglement.

Entanglement is

this very powerful
but strange connection

that exists
between pairs of particles.

Even if they're very far apart,

in a way,
they're always coordinated.

Nature's fundamental building
blocks could be connected

and influence each other
instantaneously,

as if the space between them
doesn't exist.

As if two objects can mirror
each other

without any apparent connection.

Einstein called it
"spooky action at a distance."

He rejected the idea

and tried to prove
it couldn't be real.

You could have situations

where the cause and the effect
happen at the same time.

But if entanglement isn't real,

cutting-edge technologies
could be in jeopardy.

Quantum computers,
quantum encryption...

They depend on entanglement
being a fact in the world.

Underlying it all

is a profound question:

do we live in Einstein's
universe of common-sense laws

or a bizarre quantum reality

that allows spooky connections
across space and time?

300 miles off the coast
of West Africa,

on one of the Canary Islands,

a team of physicists is setting
up a remarkable experiment

that will use almost the
entire breadth of the universe

to settle the question,

"Is the seemingly impossible
phenomenon

"of quantum entanglement

"an illusion,

or is it actually real?"

Leading the team
is Anton Zeilinger.

So we're now going up
the mountain

towards
the Roque de los Muchachos.

So everything looks perfect
today.

It's a precarious undertaking.

They've got a short window

on two of Europe's
largest telescopes.

Each one will simultaneously
focus on a different quasar...

An extremely distant galaxy

emitting huge amounts of light
from its core.

This light will be used
to control precise equipment

that must be perfectly aligned

to make measurements
on tiny subatomic particles.

Okay.

And if that isn't tricky enough,

the weather on the mountain
is notoriously unpredictable.

The team needs
perfect conditions

for the experiment to work.

In the end
it could be running smoothly

or there need to be
a couple of decisions made,

you know, in an excited state
in the last instant.

With the experiment
finally set up,

the team takes their positions.

David Kaiser
has worked on this experiment

with his colleagues

Jason Gallicchio
and Andy Friedman

for four years.

Coordinating it all
is Dominik Rauch.

The experiment is
his thesis project,

and it's been years
in the making.

But as darkness falls,

temperatures on the mountain
begin to drop.

Okay, there's bad news.

They have been told to leave
the William Herschel

because the road will be
so dangerous,

too dangerous,
so they have to go down now.

Too icy?

Yeah.
That's okay.

The next day, the team prepares
for another attempt.

They verify the equipment hasn't
been affected by the weather.

But now, the air is thick
with clouds.

Here's the humidity
at the various telescopes,

and you see
the humidity is 100%.

So as long as this lasts,

we can't do much.

The teams at both telescopes
wait.

But the clouds don't clear.

All the preparation has come
to nothing.

Time on these huge telescopes
is precious,

and theirs has run out.

This ambitious test
of quantum entanglement

must wait.

Why are physicists so determined

to put this bizarre aspect
of quantum mechanics

to the ultimate test?

To explore the beginning
of the story,

David Kaiser has come
to Brussels,

the city that Albert Einstein
traveled to in 1927

to attend a meeting
about a new theory

that described the micro-world
of atoms and tiny particles...

Quantum mechanics.

Quantum mechanics is one

of the most amazing intellectual
achievements in human history.

For the first time,

scientists were able to probe
a world that was, until then,

quite invisible to us.

Looking at the world
at the scale of atoms,

a million times smaller
than the width of a human hair.

One way to think
about the scales

is that if you take
an everyday object,

like a soccer ball...

and you enlarge
that soccer ball,

so that actually you can see
the individual atoms,

you roughly have to make it
the size of the Earth.

And then move into the planet.

Then you are in the world
of atoms and particles.

It was the nature
of fundamental particles,

which make up the world
we see around us,

that Einstein had come
to Brussels to discuss.

And it was here that Einstein
entered into a heated debate

that would lead to the discovery
of quantum entanglement...

A concept that would trouble him
for the rest of his life.

David Kaiser has come
to the place where it all began.

This is the original
Solvay Institute building.

Beautiful grand building.

And this is the place,

back in October 1927,

where the fifth
Solvay Conference was held.

This amazing, weeklong series
of discussions

on really
what the world was made of,

on the nature of matter
and the new quantum theory.

And these steps are
the very steps

on which this famous
group photograph was taken.

It's a collection

of the some of the most
brilliant people in the world.

Here in the front row,
we see Albert Einstein,

and the great Marie Curie
and Max Planck;

in the back row, standing,
the dapper Erwin Schroödinger.

And these sort of brash
20-year-olds, or mid-20s,

Werner Heisenberg
and Wolfgang Pauli.

These scientists were the
pioneers of quantum mechanics.

I had a huge version
of this photograph

up on the wall,

it was a poster
in my college dorm room.

My roommates had
their favorite bands,

and I had
the 1927 Solvay Conference,

which says a lot.

This was one of the greatest
meetings of minds

in history.

More than half were,
or would become,

Nobel Prize winners.

Their experiments were showing
that deep inside matter,

tiny particles... like atoms
and their orbiting electrons...

Were not solid little spheres.

They seemed fuzzy and undefined.

So this, this group here,

these, these were the folks

who had just been plumbing
deeper and deeper and deeper

to find what they hoped would be
a bedrock

of what the world was made of,

and to their surprise,

they found things less
and less solid as they dug in.

This world was not
tiny little bricks

that got smaller and smaller.

At some point, the bricks
gave way to this mush,

and what looked like solidity,
solidness,

in fact became very confusing

and kind of a whole new way
of thinking about nature.

The theory of quantum mechanics
presented at the meeting

was strange.

It said that a particle,
like an electron,

isn't physically real
until it's observed...

Measured by an instrument
that can detect it.

Before it's detected,

instead of being
a solid particle,

an electron is just
a fuzzy wave...

A wave of probability.

These objects,
like electrons and atoms,

when we describe mathematically
their behavior,

the only thing we can describe

is the probability of being
at one place or another.

It's like a wave

of all those different
possibilities.

It's not that the electron is
in one place or the other,

we just don't know,

it's that the electron really is
a combination

of every possible place
it could be

until we look at it.

Quantum mechanics only tells us
the probability

of a particle's properties,

like location.

The laws of nature were
no longer definite statements

about what's going to happen
next.

They were just statements
about probabilities.

And Einstein felt,
"Well, that's defeat.

"You're giving up on the heart
of what physics has been,

namely, to give a complete
description of reality."

For Einstein,

the idea that particles only pop
into existence

when they're observed

is akin to magic.

It's said he asked,

"Do you really believe
the moon is not there

when you are not looking at it?"

Outside of the formal setting
of the conference...

Bonsoir.

He challenged the most vocal
supporter of these ideas:

the great Danish physicist
Niels Bohr.

Einstein would show up
to breakfast at the hotel,

and Niels Bohr would be there,

and Einstein would present
his latest challenge.

Niels Bohr would sort of mumble
and wonder

and confer
with his younger colleagues.

They'd head off to the formal
meeting at the institute,

and somehow, every night
by suppertime,

Bohr would have an answer.

One of the observers said

that Einstein was like
a jack-in-the-box;

every day, he'd pop up
with a new challenge.

And Bohr would flip
this way and that,

and in the end, by supper,
have crushed that one,

and it would start
all over again.

To Bohr and his colleagues,

quantum mechanics not only
explained experimental results,

its mathematics were elegant
and beautiful.

And since Einstein hadn't found
flaws in their equations,

they left the Solvay meeting
feeling more confident than ever

in their ideas.

But Einstein didn't give up
his conviction

that quantum mechanics
was flawed.

And in his refusal to accept

the weird implications
of the theory,

he would wind up uncovering
something even weirder.

In 1933, with the Nazi Party
in power in Germany,

Einstein chose to settle
in America

and took a position at the
Institute for Advanced Study

in Princeton, New Jersey.

He recruited two physicists
to help him,

Nathan Rosen and Boris Podolsky.

And in 1935, at afternoon tea,

the three men spotted a possible
flaw in quantum mechanics

that would shake the
very foundations of the theory.

They noticed that the
mathematics of quantum mechanics

led to a seemingly impossible
situation.

Today, Robbert Dijkgraaf is
the director of the institute.

Apparently Podolsky would say,

"Well, Professor Einstein,

"this is very important
in your arguments

showing that quantum theory
is incomplete."

So they got
this very animated discussion

and what can happen still is,

now you have a bunch of
scientists discussing,

and at some point, someone says,
"Let's write a paper together."

So they did.

Their paper, known today as EPR,

argued that the equations
of quantum mechanics

predicted an impossible
connection between particles...

A seemingly magical effect.

It would be like having
two particles,

each hidden under a cup.

Looking at one

mysteriously causes the other
to reveal itself, too,

with matching properties.

Quantum theory suggested

this effect could happen
in the real world,

for example, with particles
of light... photons.

The equations implied
that a source of photons

could create pairs in such a way

that when we measure one,

causing it to snap
out of its fuzzy state,

the other mysteriously snaps
out of its fuzzy state

at the same instant,

with correlated properties.

The 1935 paper
that described this effect

has become Einstein's
most referenced work of all.

It has captivated generations
of physicists,

including Anton Zeilinger.

The Einstein-Podolsky-Rosen
paper fascinated me.

And I had to read it
at least five or six times

until I finally understood
what goes on.

And then it didn't let me go
again.

Another way to think
of the paired particles

is to imagine a game of chance
that's somehow rigged.

Suppose I had a pair
of quantum dice.

I put these two quantum dice
in my little cup,

throw them.

I look at them,
they show the same number... six.

I put them again in the cup,

throw them again.

Now they both show three.

I put them in again,
throw again,

now they both show one.

Point now being,
what I see here is,

I see two random processes...

Namely, each die showing
some number...

But these two random processes
do the same.

It's really mind-boggling.

How could two particles act
in unison,

even when they're separated
from each other?

Essential to the EPR argument

is that these particles can be,
can be separated

at an arbitrary distance.

One could be here at Princeton,

one could be
in the Andromeda Galaxy.

And yet, according
to quantum mechanics,

a choice to measure
something here

is somehow
instantaneously affecting

what could be said
about this other particle.

You can't go from Princeton
to Andromeda instantly,

and yet that, they argued,

is what the equations of quantum
mechanics seemed to imply,

and that, they said,

so much the worse
for quantum mechanics.

The world simply can't operate
that way.

For Einstein, this strange
effect conflicted

with the most basic concept
we use to describe reality...

Space.

For him, objects, particles,
everything that exists

is located in space.

Space, together with time,

was the key ingredient in his
theory of special relativity,

with its famous equation,
E = MC squared.

Einstein, of course, was
the master of space-time.

He thought that
if something happened here,

that shouldn't immediately
and instantaneously

change something
that is going on over there...

The principle of locality,
as we currently call it.

For Einstein,
it's simply common sense

that if objects are separated
in space,

for one to affect the other,

something must travel
between them.

And that traveling takes time.

Quantum particles acting in
unison could be explained

if they were communicating...

One particle instantly
sending a signal to the other,

telling it what properties
it should have.

But that would require a signal

traveling faster
than the speed of light,

something Einstein's theory
of special relativity

had proven impossible.

And it would mean the particles
were fuzzy and undefined

until the moment
they were observed.

Instead,

Einstein thought the particles
should be real all along.

They must carry with them
a hidden layer of deeper physics

that determines their properties
from the start.

Almost the way
that magic tricks,

while appearing mysterious,
have a hidden explanation.

But this hidden physics was
missing from quantum theory.

So Einstein, Podolsky, and Rosen
argued that quantum mechanics

was incomplete.

Podolsky was very enthusiastic
about this project.

In fact, he was so enthusiastic

that he ran
to the "New York Times"

and told them the news.

So Einstein was really upset
with Podolsky,

and apparently, he didn't speak
to him anymore.

When Niels Bohr heard
of Einstein's paper,

he wrote an obscure response,

arguing that one particle
could somehow

mysteriously influence
the other.

This seemingly impossible
phenomenon

became known
as quantum entanglement.

But Einstein dismissed it as
"spooky actions at a distance."

No one could think of
an experiment to test

whether Einstein or Bohr
was correct.

But that didn't stop
physicists and engineers

from making use
of quantum mechanics

to do new things.

In the '30s and '40s,

the debate around the EPR paper
sort of dies down.

But, quantum theory
actually takes off.

The mathematics leads to all
kinds of amazing developments.

Entanglement aside,

the equations
of quantum mechanics

enabled the scientists
of the Manhattan Project

to develop the atomic bomb.

And in the years
after the Second World War,

researchers at Bell Labs
in New Jersey

used quantum theory to develop
one of the first lasers...

In our laboratories,

men experiment with a light

once undreamed-of
in the natural world.

And build small devices

that could control
the flow of electricity...

Transistors.

It's destined to play
a vital role in your future,

your electronic future.

Transistors became
the building blocks

of the burgeoning field
of electronics.

Computers, disc drives...

The entire digital revolution
soon followed,

all made possible

by the equations
of quantum theory.

Yet Einstein's questions
about entanglement

and what it implied

about the incompleteness
of quantum mechanics

remained unanswered
until the 1960s,

when a physicist
from Northern Ireland

made a remarkable breakthrough...

John Bell.

Bell was a very talented
young physics student,

but he quickly grew dissatisfied
with what he considered almost,

almost a kind of dishonesty
among his teachers.

Bell insisted

that Einstein's questions
about quantum mechanics

had not been addressed.

He got into shouting matches
with his professors.

"Don't tell us that Bohr solved
all the problems.

This really deserves
further thought."

Quantum mechanics has been
fantastically successful.

So it is
a very intriguing situation

that at the, at the foundation

of all that impressive success,

there are these great doubts.

It's a very strange thing
that ever since the 1930s,

the idea of sitting
and thinking hard

about the foundations
of quantum mechanics

has been disreputable
among professional physicists.

When people tried to do that,

they were kicked out
of physics departments.

And so, for someone like Bell,

he needed to have a day job
doing ordinary particle physics,

but at night,
you know, hidden away,

he could do work

on the foundations
of quantum mechanics.

Bell became
a leading particle physicist

at CERN, in Geneva.

But he continued to explore
the debate

between Einstein and Bohr.

And in 1964, he published
an astonishing paper.

Bell proved

that Bohr's and Einstein's ideas
made different predictions.

If you could randomly perform
one of two possible measurements

on each particle,

and check how often
the results lined up,

the answer would reveal whether
we lived in Einstein's world...

A world that followed
common-sense laws...

Or Bohr's...

A world that was deeply strange

and allowed
spooky quantum connections.

We now know with hindsight

this was one of
the most significant articles

in the history of physics...

Not just the history
of 20th-century physics,

in the history of,
of the field as a whole.

But Bell's article appears
in this, you know,

sort of out-of-the-way journal...

In fact, the journal itself
folds a few years later.

This is not central
to the physics community.

It's sort of dutifully filed
on library shelves

and then forgotten.

It literally collects dust
on the shelf.

A few years later,
completely by chance,

a brilliant
experimental physicist

stumbled upon Bell's article.

I thought this is one
of the most amazing papers

I had ever read
in my whole life.

And I kept wondering,
"Well, gee, this is wonderful,

but where's
the experimental evidence?"

John worked on Bell's theory

with fellow physicist
Abner Shimony,

and at the University
of California, Berkeley,

started work on an experiment
to test it.

He had a talent for tinkering
in the lab

and building the parts
he needed.

I used to rummage around here

and scavenge and dumpster-dive
for old equipment.

He knew where to find hidden
storage rooms, like this,

which he could raid
to salvage spare parts

for his experiments.

This was a power supply
for diode lasers.

That looks like
something I built.

Here is a picture
of the experiment I did.

I had more hair in those days.

Here's another picture.

This is of Stu Freedman,

who worked on it with me.

Piece by piece,
John Clauser and Stuart Freedman

constructed the world's first
Bell test experiment.

They focused a laser
onto calcium atoms,

causing them to emit
pairs of photons

that the equations
of quantum theory suggested

should be entangled.

They recorded whether or not
the photons passed

through filters on each side

and checked how often
the answers agreed.

After hundreds of thousands
of measurements,

if the pairs were
more correlated

than Einstein's physics
predicted,

they must be spookily entangled.

We saw the stronger correlation

characteristic
of quantum mechanics.

We measured it,
and that is what we got.

The outcome was exactly

what Bohr's quantum mechanics
predicted.

The experiment appeared to show

that the spooky connections
of quantum entanglement

did exist in the natural world.

Could it be that the great
Albert Einstein was wrong?

Remarkably,

the first people to react
to this extraordinary result

were not the world's
leading physicists.

Ronald Reagan's definition
of a hippie

was someone who dresses
like Tarzan,

has hair like Jane,

and smells like Cheeta.

A small group
of free-thinking physicists

at the heart of San Francisco's
New Age scene

got in touch with John.

They called themselves
the Fundamental Fysiks Group.

They spelled physics with an F.

Some members would experiment
with psychedelic drugs.

I mean, they were,
they were kind of in the flow

of the kind of hippie scene.

And that group was
just mesmerized

by the question of entanglement.

The idea was just to discuss
fringe subjects

with an open mind.

And I thought, "Oh, sure!

Uh, that's kind of what I do."

They were doing their best
to link Eastern mysticism

with quantum entanglement.

They sold a lot
of popular textbooks.

There were a lot of followers.

Their books became bestsellers,

like "The Tao of Physics,"
which highlighted

that Eastern philosophy
and quantum entanglement

both described
a deep connectedness

of things in the universe.

It was the great cosmic oneness.

The group held meetings
at the iconic Esalen Institute.

It was a marvelous,
beautiful place

where they would discuss
all of these ideas.

It was right
on the Pacific Coast

with the overflow
from the hot tubs

cascading down the cliffs
into the Pacific Ocean.

To my knowledge,

no useful connections
to Eastern mysticism

were ever discovered
by the group.

But it was fun.

The Fundamental Fysiks Group

may not have uncovered
the secrets of "cosmic oneness,"

but in seeing entanglement
as central to physics,

they were decades ahead
of their time.

40 years later,

cutting-edge labs
around the world

are now racing
to harness quantum entanglement

to create revolutionary
new technologies...

like quantum computers.

In our everyday computers,

the fundamental unit
of computing is a bit,

a binary digit... zero or one.

And inside the computer,
there's all these transistors,

which are turning on and off
currents.

On is one, off is zero,

and these combinations lead
to universal computing.

With a quantum computer,

you start
with a fundamental unit

that's not a bit,
but a quantum bit,

which is not really
a zero or a one,

but it can be fluid.

A quantum bit makes use of the
fuzziness of the quantum world.

A qubit, as it's known,

can be zero or one,
or a combination of both.

A particle
or tiny quantum system

can be made into a qubit.

And today, it's not just
pairs of particles

that can be entangled.

Groups of qubits can be linked
with entanglement

to create a quantum computer.

The more qubits, the greater
the processing power.

At Google's quantum computing
laboratory in Santa Barbara,

the team has recently succeeded
in creating a tiny chip

that holds an array
of 72 qubits.

The task for researcher
Marissa Giustina

and her colleagues

is to send signals
to these microscopic qubits

to control and entangle them.

Mounted on the underside
of this plate,

we have the quantum
processing chip itself,

in essence,
a quantum playground,

you could say.

Each qubit is a quantum object

that we should be able
to control at will.

Thinking about it as...

"the faster version
of that PC over there"

would be a great slight to this.

It can be much more than that.

By using entangled qubits,

quantum computers could tackle
real-world problems

that traditional computers
simply can't cope with.

For example,

a salesman has to travel
to several cities

and wants to find
the shortest route.

Sounds easy.

But with just 30 cities,

there are
so many possible routes

that it would take
an ordinary computer,

even a powerful one,

hundreds of years
to try each one

and find the shortest.

But with a handful
of entangled qubits,

a quantum computer could resolve
the optimal path

in a fraction
of the number of steps.

There's another reason teams
like Marissa's are racing

to create a powerful
quantum computer...

Cracking secret codes.

In today's world,
everything from online shopping

to covert
military communications

is protected from hackers
using secure digital codes,

a process called encryption.

But what if hackers
could get hold

of quantum computers?

A quantum computer

could crack
our best encryption protocols

in minutes,

whereas a regular computer,

or even a super-computing
network today,

couldn't do it, you know,
given months of time.

But while quantum entanglement
may be a threat

to traditional encryption,

it also offers an even more
secure alternative...

A communication system
that the very laws of physics

protect from secret hacking.

Researchers in China
are leading the way.

Here in Shanghai,

at the University
of Science and Technology,

Jian-Wei Pan runs a leading
quantum research center.

His teams are working to harness

the properties
of the quantum world.

They can send secret messages
using a stream of photons

in a system
that instantly detects

any attempt to eavesdrop.

Jian-Wei's team

has created
a network of optical fibers

more than a thousand miles long

that can carry
secure information

from Beijing to Shanghai.

It is used by banks
and data companies.

But there's a limit to how far
quantum signals can be sent

through optical fibers.

To send signals further,

Jian-Wei's team launched

the world's first quantum
communication satellite.

Above Earth's atmosphere,
there are fewer obstacles,

and quantum particles can travel
much further.

Each night, teams on the ground
prepare to track the satellite

across the sky.

Laser guidance equipment
locks on

and allows signals to be sent
and received.

The team aims to use
this equipment

to create a new, secure
communication system

using quantum entanglement.

The satellite sends
entangled photons

to two users.

An eavesdropper could intercept
one of the entangled photons,

measure it, and
send on a replacement photon.

But it wouldn't be
an entangled photon...

Its properties wouldn't match.

It would be clear an
eavesdropper was on the line.

In theory,
this technique could be used

to create a totally secure
global communication network.

So the next step is,

we will have ground station,
for example, in Canada,

and also in Africa
and many countries.

So, we will use our satellite

for the global
quantum communication.

We want to push this technology
as far as possible.

These are the first steps

in creating a completely
unhackable quantum internet

of the future...

Made possible
by quantum entanglement.

But there's a problem.

What if quantum entanglement...

"spooky action at a distance"...

Isn't real after all?

It could mean entangled photons
are not the path

to complete security.

The question goes back

to Clauser and Freedman's
Bell test experiment.

In the years
after their pioneering work,

physicists began to test
possible loopholes

in their experiment...

Ways in which
the illusion of entanglement

might be created,

so the effect might not be
so spooky after all.

One loophole is especially hard
to rule out.

In modern Bell test experiments,
devices at each side test

whether the photons can pass
through one of two filters

that are randomly chosen,

effectively asking
one of two questions

and checking how often
the answers agree.

After thousands of photons,

if the results show
more agreement

than Einstein's physics
predicts,

the particles must be
spookily entangled.

But what if something

had mysteriously influenced
the equipment

so that the choices
of the filters

were not truly random?

Is there any common cause,

deep in the past, before
you even turn on your device,

that could have nudged
the questions to be asked

and the types of particles
to be emitted?

Maybe some strange particle,

maybe some force that had not
been taken into account,

so that what looks
like entanglement

might indeed be an accident,
an illusion.

Maybe the world still acts
like Einstein thought.

It is this loophole

that the team at
the high-altitude observatory

in the Canary Islands

is working to tackle.

With quantum mechanics
now more established than ever,

they're determined
to put entanglement

to the ultimate test,

and finally settle
the Einstein-Bohr debate

beyond all reasonable doubt.

The team is creating
a giant version

of Clauser and Freedman's
Bell test,

with the entire universe
as their lab bench.

In this "cosmic Bell test,"

the source
of the entangled particles

is about a third of a mile
from each of the detectors.

The team must send perfectly
timed pairs of photons

through the air to each side.

At the same time, the telescopes
will collect light

from two extremely far-off,
extremely bright galaxies

called quasars.

These are among the brightest
objects in the sky,

emitting light in powerful jets.

Random variations in this light

will control
which filters are used

to measure the photon pairs.

And since the quasars
are so far away...

The light has been traveling
for billions of years

to reach Earth...

It makes it incredibly unlikely

that anything could be
influencing the random nature

of the test.

If the experiment is successful,

the team will have tackled
the loophole

and shown
that quantum entanglement

is as spooky
as Bohr always claimed.

Dominik and Jason are
at one telescope.

Hello, Anton.

Anton is at the other.

With clear skies
finally overhead,

the huge telescopes awaken...

poised to collect light
from distant quasars.

Moving.

All right.

Dark count level.

Okay, this is good.

So we're doing everything...

everything at once now.

So the guys for the links

are setting the state
of the entangled photon pair.

We're trying to acquire
the quasar.

We're just centering it

and making the field of view
as small as possible,

to be sure that we only have
the quasar.

Okay.

It's guiding now?
Yes.

Let's wait for one more image.

Okay.
Of this one.

All right.

Great, great, great,
great, great.

Yeah, that's good.

Looks like, 90,

let's say 91 to be conservative,
of purity.

With the telescopes
now locked on

to two different quasars,

the team begins
to take readings.

The red counts, 12,000.

Blue counts, 7,000.

We did a full,
the full cosmic Bell test.

What?

Yeah, we're doing
a full cosmic Bell test.

It's working.

Light from the quasars is
selecting which filters are used

to measure
the entangled photons.

It is exciting.

It is.

Now we do have a test,

but it's not clear
what the outcome will be.

Moving.

All right.

Everything is exactly the same,
beautiful, perfect, yeah.

Two months later,
back in Vienna,

the team analyzes
the experimental data.

This might take a second.

The numbers look really great.

And it is extremely pleasing
to see

that all this worked so nice.

We clearly see correlations

that correspond
to quantum mechanics.

The results show entanglement.

And since the light
from the quasars

controlling the test

was nearly
eight billion years old,

it's extremely unlikely

that anything could have
affected its random nature.

This remaining loophole seems
to be closed.

The experiment we did
is just fantastic.

The big cosmos comes down

to control
a small quantum experiment.

That, that in itself is a,
is, is beautiful.

You know, honestly, I still,
I still get chills.

I mean...

when I realize what our team
was able to do,

in this intellectual journey
that stretches back

to the early years
of the 20th century.

There's, there's hardly
any room left

for a kind of alternative,
Einstein-like explanation.

We haven't ruled it out,

but we've shoved it into
such a tiny corner of the cosmos

as to make it
even more implausible

for anything
other than entanglement

to explain our results.

Accepting that entanglement
is a part

of the natural world around us

has profound implications.

It means we must accept
that an action in one place

can have an instant effect
anywhere in the universe,

as if there's no space
between them.

Or that particles
only take on physical properties

when we observe them.

Or we must accept both.

We're left with conclusions
about the universe

that make no sense whatsoever.

Science is stepping outside
of all of our boundaries

of common sense.

It's almost like being
in "Alice in Wonderland," right?

Where everything is possible.

It was first seen

as an unwelcome
but unavoidable consequence

of quantum mechanics.

Now, after nearly a century
of disputes and discoveries,

"spooky action at a distance"

is finally at the heart
of modern physics.

At the Institute
for Advanced Study,

where the concept
of entanglement

was first described,

researchers are now using it

in their search for a single
unified theory of the universe...

The holy grail of physics.

Einstein's theories of special
and general relativity

perfectly describe
space, time, and gravity

at the largest scales
of the universe,

while quantum mechanics
perfectly describes

the tiniest scales.

Yet these two theories have
never been brought together.

So far, we have not yet had
a single complete theory

that is both quantum mechanical

and reproduces the prediction

of Einstein's wonderful theory
of general relativity.

Maybe the secret
is entanglement.

What if space itself
is actually created

by the tiny quantum world?

Just like temperature,
warm and cold,

consists simply of the movement
of atoms inside an object,

perhaps space as we know it

emerges from networks
of entangled quantum particles.

It's a mind-blowing idea.

What we are learning these days

is that we might have to give up
that what Einstein holds sacred,

namely, space and time.

So, he was always thinking,

"Well, we have little pieces
of space and time,

and out of this,
we build the whole universe."

In a radical theory... known
as the holographic universe...

Space and time are created
by entangled quantum particles

on a sphere
that's infinitely far away.

What's happening in space

in some sense all described

in terms of a screen
outside here.

The ultimate description
of reality

resides on this screen.

Think of it as kind of quantum
bits living on that screen.

And this,
like a movie projector,

creates a illusion of
the three-dimensional reality

that I'm now experiencing.

It may be impossible
to intuitively understand

this wild mathematical idea,

but it suggests

that entanglement could be

what forms the true fabric
of the universe.

The most puzzling element
of entanglement,

that, you know, somehow two
points in space can communicate,

becomes less of a problem,

because space itself
has disappeared.

In the end, we just have
this quantum mechanical world.

There is no space anymore.

And so in some sense,
the paradoxes of entanglement...

The EPR paradox
disappears into thin air.

Truly understanding
quantum mechanics

will only happen
when we put ourselves

on the entanglement side,

and we stop privileging
the world that we see

and start thinking
about the world

as it actually is.

Science has made
enormous progress for centuries

by sort of breaking complicated
systems down into parts.

When we come to a phenomenon
like quantum entanglement,

that scheme breaks.

When it comes to the bedrock
of quantum mechanics,

the whole is more
than the sum of its parts.

The basic motivation is

just to learn how nature works.

What's really going on?

Einstein said it very nicely.

He's not interested
in this detailed question

or that detailed question.

He just wanted to know

what were God's thoughts
when He created the world.

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