Are We Ready for Quantum Computing

[Music]

in 1988

when i’d studied computer science

electronics engineering

applied physics i’d done some research

on information theory

and i’d spent three years working on

designing electronics electronic systems

to prevent

lighting systems

industrial lighting systems from blowing

up

in the trade this is known as a a

non-passive

failure and at the time i was in the uk

working in research

working on these electronic systems and

i can remember at the time

hearing about the very first quantum

bits qubits

1988 now among the engineering and

scientific community

this was a client a little bit of a

sensation

but everywhere else it didn’t really uh

didn’t really

raise any eyebrows people didn’t really

notice it

but back then i thought oh this is this

could be interesting

something interesting could come out of

this

a year later i moved to germany

having fixed the problem with the

exploding light bulbs

and i became a midwife to the world wide

web

and back then this clunky

buggy document hypertext system

the very first of its kind scalable

hypertext system

we were working on this and i remember

thinking

and my colleagues as well this is

probably going to change

a lot this is probably going to be a

fundamentally new kind of technology

we didn’t realize it would be things

like cat videos and

fake news and cyber wars

and world of warcraft but

we did think it something momentous

would have would happen

i think if at the time if you’d asked

anybody generally about

the impact of the web people will just

have said

it’s a neat way to write documents

that’s all

but what the world wide web did for us

was give us a new way

to present information and a new way

to interact with each other

this interaction and information

presentation

was fundamental paradigm shift something

fundamentally new

it allowed a new level of

interaction between people

and at the time the

implications of that as i said were not

clear it’s

perhaps a coincidence that at the same

time of course

we had this beginnings of

quantum computing the first qubits

but if you want to

understand a little bit about quantum

computing we need a metaphor

we need some kind of stabilizer wheels

of kids when they learn to ride a

bicycle

they have stabilizer wheels we need

stabilizer wheels

and our stabilizer wheels today

are going to be coins and balls

so if you throw a coin

a thousand times then give or take

a standard deviation you’ll get 500

heads

and 500 tails incidentally the standard

deviation

the actual number of coins you see when

you toss a thousand coins

uh bears a very very deep mathematical

relationship

to the distribution of prime numbers

it’s not relevant here but it’s an

interesting fact

if you have two coins then

when you throw them both then

some of the time you’ll get in heads

plus heads head

plus tail tail plus heads tails plus

tails

and each of those variants will also

they will occur 250 times

plus or minus a standard deviation and

with three coins

eight different variations each one

occurring

125 times

for quantum computing we need a

different module

model this is where the ball comes in

now if we take this ball here and we

define a some arbitrary point on its

surface

say here

if we spin the ball and then stop it

then that point on the surface

is just as likely to point in one

direction as in any other direction

and we can describe that with two angles

an angle we call the azimuth

which is this way and an angle we call

the elevation

this way strictly speaking we also need

to know the size of the ball

but physicists are very clever about

cheating so normally in physics we

define the radius of the ball to be one

that makes the mathematics

very easy and some of the calculations

very simple

this is our simple model of a qubit

quantum bit

like a ball a qubit has a specific state

a specific

direction when we look at it

the interesting thing happens

when we put the ball on the cubit

behind a screen or inside a bag

just imagine that you can’t look inside

this bag it’s transparent for a reason

so you can see what’s happening so just

imagine that

we’ve got a spinning ball in here

something’s happening to it

with a quantum bit with a qubit

that ball can be in many possible

states have many possible positions at

the same time

we call this superposition also we can

link two

balls together so that the position the

direction of one of them completely

determines

the position and direction of the other

one and vice versa

you can even put three of them in there

or as many as you want

we call that entanglement

and entanglement and superposition are

the fundamental principles

of quantum mechanics the question then

becomes how can we use that

we need to convert these qubits

into bits the simplest example is if you

imagine a qubit

and you imagine that it’s you’ve done

something to it and it’s now

pointing at the equator

if we repeat that experiment like the

coin a thousand times

then 500 times we will measure it as

pointing upwards and 500 times

downwards so it’s just like a coin

the interesting part happens of course

when we’ve prepared the qubit in the

right way

when we’ve entangled the qubits in the

right way

then that’s no longer the case

then each qubit will favor a one or a

zero more

than just with a coin we found a way to

get

inside or behind the pure probability of

the coin

by using quantum mechanics the

trick with quantum computing is to

construct these interactions between the

balls between the qubits

in such a way that the right answers the

answer you’re looking for

occurs more often and the answers you’re

not looking for

occur less often we call this

constructive and destructive

interference and this is the principle

behind every quantum program in order

to understand how that actually works we

need to look a little bit at the

history how quantum computers actually

came into being in 1973

a man called charles bennett this is an

extract from his

scientific paper um

don’t worry you’re not supposed to

understand it he showed

that any computer program

can be reconstructed so it’s reversible

and that’s important because that means

that you can execute the computer

program

get it to produce a result and then run

it backwards

so that you’re in the initial state you

were when you started

this is important because it allows us

to now construct programs with quantum

mechanical systems

in other words we can run a quantum

program to produce a result

without actually changing anything this

is a major step

a few years later in 1988

when i was when i was fighting my

exploding light bulbs

the very first qubits were invented

and a few years later a physicist

called richard feyman came up with a

proof

that you could actually use these kinds

of programs to solve

problems a particular problem which was

infeasible to solve on a classical

computer

it was so complex and so difficult the

classical computer would never be able

to solve it

but a quantum computer was trivial

that changed again in 1994

when peter shaw developed an algorithm

for factoring numbers

factoring numbers is a difficult problem

we know that 5 times 3 is 15.

5 and 3 are the factors of 15. if we

want to factor a thousand bit number

and even with the biggest supercomputer

we have today this would take millions

or billions of years peter shaw’s

algorithm sped that up

and if we had a perfect quantum computer

it would mean we could factor such

numbers in weeks or days or maybe even

hours or minutes that was the

really the birth and the impetus that

quantum computing

needed

quantum computers are very beautiful

this is the inside of one

i i like to think that the reason they

are beautiful is because form follows

function

and quantum computing the function of

quantum computing is as fundamental as

it gets

we’re now at the stage where we have

quantum computers we’re able to use them

we’re able to program them we’re

searching for

better industrializable more robust more

stable

technologies we’re learning how to write

algorithms for them

we’re working on different types of

quantum computing different types of

qubit

different types of chips for doing this

so we’re now out of the stage of what we

call quantum the quantum physical era

we’re now in the stage of the era of

quantum readiness

and i see this when i look at the number

of students attending

university courses on quantum computing

or the number of attendees on

online summer schools and classes the

numbers

are astounding we are now at the stage

where

we’re getting ready to go into the phase

of quantum advantage and quantum

advantage means

the point where quantum computers

overtake classical computers

become so performant that they are

solving problems

way beyond what we will ever be able to

do

on current computers

we have quantum computers the technology

is starting to mature

and the question is are we ready for

quantum computers

i think we are i’d like to encourage you

to

everybody out there everybody here

you have access to completely free

quantum computers

you can try it out it’s very simple

give it a go i think we’re ready for

quantum computers computers

i’d like to invite you to join me on the

journey

to try this out and learn this

technology anybody want some qubits

thank you