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The Quantum Internet | Stephanie Wehner | TEDxVienna


[Music]

[Music] I want to ask you a question what

I want to ask you a question what

I want to ask you a question what happened on the 29th of October 1969

happened on the 29th of October 1969

happened on the 29th of October 1969 landing on the moon close but on this

landing on the moon close but on this

landing on the moon close but on this day something equally enormous happened

day something equally enormous happened

day something equally enormous happened namely the first message was sent over

namely the first message was sent over

namely the first message was sent over the Internet

so let me explain just how difficult it

so let me explain just how difficult it actually was to send that first message

actually was to send that first message

actually was to send that first message so the internet was super tiny and at

so the internet was super tiny and at

so the internet was super tiny and at half-past 10:00 in the evening

half-past 10:00 in the evening

half-past 10:00 in the evening researchers had gathered down in Los

researchers had gathered down in Los

researchers had gathered down in Los Angeles and at Stanford up in Menlo Park

Angeles and at Stanford up in Menlo Park

Angeles and at Stanford up in Menlo Park to send the first test message and they

to send the first test message and they

to send the first test message and they had agreed to send the message log in

had agreed to send the message log in

had agreed to send the message log in like looking into a remote computer and

like looking into a remote computer and

like looking into a remote computer and because this was challenging they called

because this was challenging they called

because this was challenging they called each other on the phone make sure

each other on the phone make sure

each other on the phone make sure message arrived so there were these guys

message arrived so there were these guys

message arrived so there were these guys down in Los Angeles at the computer and

down in Los Angeles at the computer and

down in Los Angeles at the computer and they type the first letter L and he

they type the first letter L and he

they type the first letter L and he asked on the phone did you see the L an

asked on the phone did you see the L an

asked on the phone did you see the L an excited message comes back yes yes we

excited message comes back yes yes we

excited message comes back yes yes we see the L and we sent the first letter

see the L and we sent the first letter

see the L and we sent the first letter over the internet they typed the second

over the internet they typed the second

over the internet they typed the second letter Bo and asked again did you see

letter Bo and asked again did you see

letter Bo and asked again did you see the O and he said yes we also see the O

the O and he said yes we also see the O

the O and he said yes we also see the O and they typed the letter G and the

and they typed the letter G and the

and they typed the letter G and the system crashed

so the Internet is a little bit larger

so the Internet is a little bit larger now and we use it to send vast

now and we use it to send vast

now and we use it to send vast quantities of data I’ve recently moved

quantities of data I’ve recently moved

quantities of data I’ve recently moved into a new apartment and just like in

into a new apartment and just like in

into a new apartment and just like in many places in the world I sign up for

many places in the world I sign up for

many places in the world I sign up for internet like you sign up for power or

internet like you sign up for power or

internet like you sign up for power or water the Internet is everywhere and it

water the Internet is everywhere and it

water the Internet is everywhere and it certainly changed the way that we live

certainly changed the way that we live

certainly changed the way that we live today so I’m working on a quantum

today so I’m working on a quantum

today so I’m working on a quantum internet because I believe that it will

internet because I believe that it will

internet because I believe that it will similarly revolutionize the world so of

similarly revolutionize the world so of

similarly revolutionize the world so of course you’re asking now what is this

course you’re asking now what is this

course you’re asking now what is this quantum Internet so on the surface it

quantum Internet so on the surface it

quantum Internet so on the surface it looks a lot like a classical Internet

looks a lot like a classical Internet

looks a lot like a classical Internet there’s computers and we’re gonna send

there’s computers and we’re gonna send

there’s computers and we’re gonna send data from one computer to another only

data from one computer to another only

data from one computer to another only on the quantum Internet this is a

on the quantum Internet this is a

on the quantum Internet this is a quantum computer and I’m sending quantum

quantum computer and I’m sending quantum

quantum computer and I’m sending quantum data quantum bits or qubits from one

data quantum bits or qubits from one

data quantum bits or qubits from one place to another so these qubits are

place to another so these qubits are

place to another so these qubits are pretty special for example we cannot

pretty special for example we cannot

pretty special for example we cannot copy a qubit unlike a classical bit that

copy a qubit unlike a classical bit that

copy a qubit unlike a classical bit that can be either 0 or 1

can be either 0 or 1

can be either 0 or 1 a qubit can be both 0 and 1 at the same

a qubit can be both 0 and 1 at the same

a qubit can be both 0 and 1 at the same time so you might imagine that instead

time so you might imagine that instead

time so you might imagine that instead of sending pictures of a cat that is

of sending pictures of a cat that is

of sending pictures of a cat that is either dead or alive we are going to

either dead or alive we are going to

either dead or alive we are going to send a Schrodinger’s cat that is both

send a Schrodinger’s cat that is both

send a Schrodinger’s cat that is both dead and alive or 0 and 1 at the same

dead and alive or 0 and 1 at the same

dead and alive or 0 and 1 at the same time so these qubits are pretty cool but

time so these qubits are pretty cool but

time so these qubits are pretty cool but it brings us to the question why do we

it brings us to the question why do we

it brings us to the question why do we want to send them around so a quantum

want to send them around so a quantum

want to send them around so a quantum Internet has many applications that are

Internet has many applications that are

Internet has many applications that are impossible on the Internet today it can

impossible on the Internet today it can

impossible on the Internet today it can make many things more efficient and in

make many things more efficient and in

make many things more efficient and in fact to use the quantum Internet

fact to use the quantum Internet

fact to use the quantum Internet you also don’t need to have a large

you also don’t need to have a large

you also don’t need to have a large quantum computer at home

so probably the most famous application

so probably the most famous application of a quantum internet is to use it for

of a quantum internet is to use it for

of a quantum internet is to use it for secure communication so secure

secure communication so secure

secure communication so secure communication means that I am going to

communication means that I am going to

communication means that I am going to send data to you like my credit card

send data to you like my credit card

send data to you like my credit card information or maybe state secrets and I

information or maybe state secrets and I

information or maybe state secrets and I want that no one is able to listen into

want that no one is able to listen into

want that no one is able to listen into this communication a quantum internet

this communication a quantum internet

this communication a quantum internet allows us to use quantum key

allows us to use quantum key

allows us to use quantum key distribution that enables secure

distribution that enables secure

distribution that enables secure communication whose security relies only

communication whose security relies only

communication whose security relies only on the laws of quantum mechanics in

on the laws of quantum mechanics in

on the laws of quantum mechanics in particular it’s secure even if some

particular it’s secure even if some

particular it’s secure even if some eavesdropper was trying to snoop into

eavesdropper was trying to snoop into

eavesdropper was trying to snoop into our communication has a quantum computer

our communication has a quantum computer

our communication has a quantum computer and it remains secure even if this

and it remains secure even if this

and it remains secure even if this eavesdropper buys a quantum computer

eavesdropper buys a quantum computer

eavesdropper buys a quantum computer tomorrow so that’s pretty nice but the

tomorrow so that’s pretty nice but the

tomorrow so that’s pretty nice but the quantum Internet has many other possibly

quantum Internet has many other possibly

quantum Internet has many other possibly less well-known applications which

less well-known applications which

less well-known applications which personally I find probably even more

personally I find probably even more

personally I find probably even more exciting using a quantum Internet we can

exciting using a quantum Internet we can

exciting using a quantum Internet we can use a quantum computer in the cloud so

use a quantum computer in the cloud so

use a quantum computer in the cloud so quantum computers promise to solve many

quantum computers promise to solve many

quantum computers promise to solve many problems much faster than a classical

problems much faster than a classical

problems much faster than a classical computer in particular we think that

computer in particular we think that

computer in particular we think that they’re extremely good at simulating

they’re extremely good at simulating

they’re extremely good at simulating problems in quantum chemistry so you

problems in quantum chemistry so you

problems in quantum chemistry so you might imagine that in the future if you

might imagine that in the future if you

might imagine that in the future if you want to explore a new material or a new

want to explore a new material or a new

want to explore a new material or a new medicine you don’t first go into the lab

medicine you don’t first go into the lab

medicine you don’t first go into the lab and with some hugely long time consuming

and with some hugely long time consuming

and with some hugely long time consuming experiment but you’re first going to run

experiment but you’re first going to run

experiment but you’re first going to run the quick simulation on your quantum

the quick simulation on your quantum

the quick simulation on your quantum computer to see whether that makes sense

computer to see whether that makes sense

computer to see whether that makes sense at all now quantum computers are pretty

at all now quantum computers are pretty

at all now quantum computers are pretty expensive I sort of expected I will

expensive I sort of expected I will

expensive I sort of expected I will actually be dead by the time that we all

actually be dead by the time that we all

actually be dead by the time that we all have a quantum computer at home or in

have a quantum computer at home or in

have a quantum computer at home or in our office but of course we want to use

our office but of course we want to use

our office but of course we want to use this computing power

this computing power

this computing power so the first quantum computers are

so the first quantum computers are

so the first quantum computers are likely going to be somewhere in the

likely going to be somewhere in the

likely going to be somewhere in the cloud and I’m going to pay say to use

cloud and I’m going to pay say to use

cloud and I’m going to pay say to use that for an hour

now maybe I want to use this quantum

now maybe I want to use this quantum computer to perform a simulation on some

computer to perform a simulation on some

computer to perform a simulation on some proprietary material or possibly even my

proprietary material or possibly even my

proprietary material or possibly even my own DNA so I don’t want to give my DNA

own DNA so I don’t want to give my DNA

own DNA so I don’t want to give my DNA to this quantum computer so it turns out

to this quantum computer so it turns out

to this quantum computer so it turns out that using a quantum internet we can use

that using a quantum internet we can use

that using a quantum internet we can use this remote quantum computer in the

this remote quantum computer in the

this remote quantum computer in the cloud securely in the sense that it has

cloud securely in the sense that it has

cloud securely in the sense that it has no idea what we’re going to use it for

quantum Internet can also do all kinds

quantum Internet can also do all kinds of other cool things like it’s good at

of other cool things like it’s good at

of other cool things like it’s good at synchronizing clocks much more

synchronizing clocks much more

synchronizing clocks much more accurately than we can do classically it

accurately than we can do classically it

accurately than we can do classically it can be used to enhance password

can be used to enhance password

can be used to enhance password identification to some server far away

identification to some server far away

identification to some server far away and curiously we can even use it to play

and curiously we can even use it to play

and curiously we can even use it to play better at an online game so what is it

better at an online game so what is it

better at an online game so what is it about these qubits that is so special

about these qubits that is so special

about these qubits that is so special that it enables all these applications

that it enables all these applications

that it enables all these applications to qubits can be entangled using a

to qubits can be entangled using a

to qubits can be entangled using a quantum Internet

now entanglement also still sounds

now entanglement also still sounds pretty mysterious but there’s actually

pretty mysterious but there’s actually

pretty mysterious but there’s actually only two features of quantum

only two features of quantum

only two features of quantum entanglement that lie at the bottom of

entanglement that lie at the bottom of

entanglement that lie at the bottom of all of these applications so if you

all of these applications so if you

all of these applications so if you understand these two features you will

understand these two features you will

understand these two features you will have a pretty good intuition of what a

have a pretty good intuition of what a

have a pretty good intuition of what a quantum Internet is good for so what are

quantum Internet is good for so what are

quantum Internet is good for so what are these two features so the first one is

these two features so the first one is

these two features so the first one is called maximum coordination let’s say

called maximum coordination let’s say

called maximum coordination let’s say I’ve used the quantum Internet to

I’ve used the quantum Internet to

I’ve used the quantum Internet to entangle a qubit here in Vienna with

entangle a qubit here in Vienna with

entangle a qubit here in Vienna with some cubed far away somewhere down in

some cubed far away somewhere down in

some cubed far away somewhere down in Sydney and I’m going to perform a

Sydney and I’m going to perform a

Sydney and I’m going to perform a measurement on my qubits and let’s

measurement on my qubits and let’s

measurement on my qubits and let’s imagine a friend down in sydney performs

imagine a friend down in sydney performs

imagine a friend down in sydney performs exactly the same measurement now if you

exactly the same measurement now if you

exactly the same measurement now if you make the same measurement we will get

make the same measurement we will get

make the same measurement we will get the same measurement outcome

the same measurement outcome

the same measurement outcome instantaneously you can think of a

instantaneously you can think of a

instantaneously you can think of a measurement as asking a question to a

measurement as asking a question to a

measurement as asking a question to a qubit I can ask qubits are you pointing

qubit I can ask qubits are you pointing

qubit I can ask qubits are you pointing left

left

left or are you pointing right and if I ask

or are you pointing right and if I ask

or are you pointing right and if I ask the question to Mike you eat here in

the question to Mike you eat here in

the question to Mike you eat here in Vienna and my friend asks the same

Vienna and my friend asks the same

Vienna and my friend asks the same question down in Sydney then if I see

question down in Sydney then if I see

question down in Sydney then if I see left he will see left and if I see right

left he will see left and if I see right

left he will see left and if I see right he was he right

he was he right

he was he right and this happens instantaneously even

and this happens instantaneously even

and this happens instantaneously even though the answer is not determined

though the answer is not determined

though the answer is not determined ahead of time and the cool thing is that

ahead of time and the cool thing is that

ahead of time and the cool thing is that it actually works for any question that

it actually works for any question that

it actually works for any question that we might have asked to disk you bit if I

we might have asked to disk you bit if I

we might have asked to disk you bit if I had asked you red or green we would have

had asked you red or green we would have

had asked you red or green we would have seen exactly the same we get always the

seen exactly the same we get always the

seen exactly the same we get always the same answer so entanglement is maximally

same answer so entanglement is maximally

same answer so entanglement is maximally coordinated and it is this feature that

coordinated and it is this feature that

coordinated and it is this feature that makes it naturally so suited for tasks

makes it naturally so suited for tasks

makes it naturally so suited for tasks that require coordination or

that require coordination or

that require coordination or synchronization so remember I said there

synchronization so remember I said there

synchronization so remember I said there were two features of quantum

were two features of quantum

were two features of quantum entanglement so what is this second

entanglement so what is this second

entanglement so what is this second feature the second feature of quantum

feature the second feature of quantum

feature the second feature of quantum entanglement is that it’s inherently

entanglement is that it’s inherently

entanglement is that it’s inherently private if I have two qubits and they’re

private if I have two qubits and they’re

private if I have two qubits and they’re completely entangled with each other

completely entangled with each other

completely entangled with each other then it’s physically impossible for any

then it’s physically impossible for any

then it’s physically impossible for any other qubit or actually anything else in

other qubit or actually anything else in

other qubit or actually anything else in the universe to have any share of this

the universe to have any share of this

the universe to have any share of this entanglement this means that if I have a

entanglement this means that if I have a

entanglement this means that if I have a qubit that is completely entangled with

qubit that is completely entangled with

qubit that is completely entangled with your qubit no one else can have a share

your qubit no one else can have a share

your qubit no one else can have a share of the entanglement our to entangle

of the entanglement our to entangle

of the entanglement our to entangle qubits form a private connection that no

qubits form a private connection that no

qubits form a private connection that no one else can share so entanglement

one else can share so entanglement

one else can share so entanglement cannot be shared and it’s inherently

cannot be shared and it’s inherently

cannot be shared and it’s inherently private and it’s this feature that makes

private and it’s this feature that makes

private and it’s this feature that makes it naturally very suited for secure

it naturally very suited for secure

it naturally very suited for secure communication remember these two

communication remember these two

communication remember these two features

features

features it’s maximally coordinated and

it’s maximally coordinated and

it’s maximally coordinated and inherently private so now I’ve told you

inherently private so now I’ve told you

inherently private so now I’ve told you all these things about qubits and

all these things about qubits and

all these things about qubits and entanglement but given that quantum

entanglement but given that quantum

entanglement but given that quantum entanglement is so cool you might ask

entanglement is so cool you might ask

entanglement is so cool you might ask why don’t we have a quantum intimate yet

it turns out that we can actually send

it turns out that we can actually send qubits over short distances

qubits over short distances

qubits over short distances you can go online and actually buy a

you can go online and actually buy a

you can go online and actually buy a commercially available box that performs

commercially available box that performs

commercially available box that performs quantum key distribution quantum secure

quantum key distribution quantum secure

quantum key distribution quantum secure communication over standard telecom

communication over standard telecom

communication over standard telecom fiber over distances of roughly 100

fiber over distances of roughly 100

fiber over distances of roughly 100 kilometers so the real challenge in

kilometers so the real challenge in

kilometers so the real challenge in building a quantum Internet is to get

building a quantum Internet is to get

building a quantum Internet is to get these qubits to travel further than

these qubits to travel further than

these qubits to travel further than these hundred kilometers so of course

these hundred kilometers so of course

these hundred kilometers so of course you might be asking why is it so

you might be asking why is it so

you might be asking why is it so difficult for these qubits to traverse

difficult for these qubits to traverse

difficult for these qubits to traverse long distances if I wanted to send a

long distances if I wanted to send a

long distances if I wanted to send a qubit down a communication line we are

qubit down a communication line we are

qubit down a communication line we are sending a single photon one particle of

sending a single photon one particle of

sending a single photon one particle of light so you can imagine that if I take

light so you can imagine that if I take

light so you can imagine that if I take one single particle of light and I send

one single particle of light and I send

one single particle of light and I send it down a communication line very soon

it down a communication line very soon

it down a communication line very soon it will be lost

remember that also qubits cannot be

remember that also qubits cannot be copied so if it’s lost it’s gone

copied so if it’s lost it’s gone

copied so if it’s lost it’s gone I cannot resend and try again so how can

I cannot resend and try again so how can

I cannot resend and try again so how can we hope to send these qubits over long

we hope to send these qubits over long

we hope to send these qubits over long distances so fortunately as as I

distances so fortunately as as I

distances so fortunately as as I mentioned we can actually send them over

mentioned we can actually send them over

mentioned we can actually send them over short distances so let’s put like a box

short distances so let’s put like a box

short distances so let’s put like a box in the middle and the box is not so far

in the middle and the box is not so far

in the middle and the box is not so far away from the left and it’s not so far

away from the left and it’s not so far

away from the left and it’s not so far away from the right namely close enough

away from the right namely close enough

away from the right namely close enough that I can send qubits both from the

that I can send qubits both from the

that I can send qubits both from the left and from the right to the box all

left and from the right to the box all

left and from the right to the box all right

right

right let’s try that what we’re going to do is

let’s try that what we’re going to do is

let’s try that what we’re going to do is we’re going to take two entangled qubits

we’re going to take two entangled qubits

we’re going to take two entangled qubits on their left and I’m going to send one

on their left and I’m going to send one

on their left and I’m going to send one of them to the box box is not far away

of them to the box box is not far away

of them to the box box is not far away so we can do that I’m going to take

so we can do that I’m going to take

so we can do that I’m going to take another two qubits which are entangled

another two qubits which are entangled

another two qubits which are entangled I’m going to send one of them to the box

I’m going to send one of them to the box

I’m going to send one of them to the box so now we have entanglement with this

so now we have entanglement with this

so now we have entanglement with this box so the cool thing is that there is a

box so the cool thing is that there is a

box so the cool thing is that there is a procedure called entanglement swapping

procedure called entanglement swapping

procedure called entanglement swapping with which we can glue this entanglement

with which we can glue this entanglement

with which we can glue this entanglement together and create entanglement over

together and create entanglement over

together and create entanglement over the entire distance that’s pretty cool

the entire distance that’s pretty cool

the entire distance that’s pretty cool so such a box is called a quantum

so such a box is called a quantum

so such a box is called a quantum repeater and we can use it to make

repeater and we can use it to make

repeater and we can use it to make entanglement over long distances but

entanglement over long distances but

entanglement over long distances but you’re probably saying what about this

you’re probably saying what about this

you’re probably saying what about this entanglement you promised us that we

entanglement you promised us that we

entanglement you promised us that we could send my Schrodinger cats this

could send my Schrodinger cats this

could send my Schrodinger cats this particular data qubits that I want to

particular data qubits that I want to

particular data qubits that I want to send somewhere else so there’s a nice

send somewhere else so there’s a nice

send somewhere else so there’s a nice feature of quantum that if we have

feature of quantum that if we have

feature of quantum that if we have entanglement we can now send a data

entanglement we can now send a data

entanglement we can now send a data qubit by teleporting it across so we I

qubit by teleporting it across so we I

qubit by teleporting it across so we I take my yellow data qubit and i teleport

take my yellow data qubit and i teleport

take my yellow data qubit and i teleport it to the other side

so this way we can send qubits over long

so this way we can send qubits over long distances so we’re probably saying you

distances so we’re probably saying you

distances so we’re probably saying you know this talk is getting more

know this talk is getting more

know this talk is getting more fantastical by the minute

fantastical by the minute

fantastical by the minute first there are these qubits now are we

first there are these qubits now are we

first there are these qubits now are we even going to teleport them around so we

even going to teleport them around so we

even going to teleport them around so we are actually actively working on this

are actually actively working on this

are actually actively working on this box

box

box the quantum repeater and by 2020 we

the quantum repeater and by 2020 we

the quantum repeater and by 2020 we wanted to have the first demonstration

wanted to have the first demonstration

wanted to have the first demonstration network in the Netherlands that

network in the Netherlands that

network in the Netherlands that showcases this box

showcases this box

showcases this box the quantum repeater it might become the

the quantum repeater it might become the

the quantum repeater it might become the first quantum Internet in the world that

first quantum Internet in the world that

first quantum Internet in the world that actually connects small quantum

actually connects small quantum

actually connects small quantum computers small quantum processors in

computers small quantum processors in

computers small quantum processors in such a way that we can send qubits from

such a way that we can send qubits from

such a way that we can send qubits from any of these quantum computers to

any of these quantum computers to

any of these quantum computers to another we can make entanglement between

another we can make entanglement between

another we can make entanglement between any of the

any of the

any of the two cities so you can sort of think that

two cities so you can sort of think that

two cities so you can sort of think that we are now on the edge of the quantum

we are now on the edge of the quantum

we are now on the edge of the quantum 1969 and in 2020 we want to send the

1969 and in 2020 we want to send the

1969 and in 2020 we want to send the first quantum message over what might be

first quantum message over what might be

first quantum message over what might be the first quantum Internet thank you

the first quantum Internet thank you

the first quantum Internet thank you very much

very much

very much [Applause]

”

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