Quantum the power of the little things

[Music]

you live in the quantum world

you take advantage of it every single

day

and you don’t even know what it means

in the morning you wake up

you have a shower

you fry your eggs toast your bread for

your coffee

you brush your teeth pack your laptop

take your

phone

close the door and run for the tram that

is one hour of your daily life sponsored

by at least

one million

of scientific discoveries

i’m here as a quantum researcher to tell

you

why quantum mechanics is amazing

and how quantum computers are going to

change

your lives

as scientists we really try to explain

the world we want to explain the

phenomena and the effects that we see

around

we see that something is moving around

and we want to predict its trajectory

or we feel that something is like

heating up or even bursting and we want

to understand why this is happening so

all these things were already observed

and explained long time ago

when i was a long time ago i’m talking

like a few centuries those are the

classics so things like gravity

thermodynamics

maybe electromagnetism they were

explained long time ago

but human curiosity wanted to go a

little bit farther

so humans are starting to look into the

really small tiny things

at some point they found things like

atoms photons or electrons and they

could no longer explain what was

happening with these little particles

using the set of laws that they were

using for the bigger things

so they realized they needed a new set

of laws

so in the 1920s very important and

renowned scientists like schrodinger

heisenberg bohr came up with the first

mathematical framework for quantum

physics

and that was really revolutionary

because from that moment on we would

distinguish the world into two different

worlds

so we would have the set of laws that

would explain the classical mechanics

and we would have also the set of laws

that would explain the little things the

quantum particles

so

actually

this was really a big thing

and it changed the whole thing

but i want to bring another

differentiation here today

and this distinction is about what was

told to us and what is untold to us

so let me try to explain this a little

bit

when we are children when we are at the

school we believe everything our

teachers tell us

i’m not saying we shouldn’t have i’m not

saying they were lying to us i’m just

saying whatever they would tell us we

would be like

and so they would tell us about gravity

and if you really think about it gravity

it’s amazing it’s even unbelievable

there is like an imaginary transparent

invisible force that is like pulling you

down 24 7. and nobody questions it

everybody is like oh yeah gravity i’ve

heard of it yeah

but what about those things that we

weren’t told about this is quantum

physics

because of that because we never heard

about it because our teachers didn’t

tell us about it we feel really

disconnected to this world

we feel so disconnected the only thing

we know about it is that it’s difficult

to understand counterintuitive so we

just don’t even give it a try

but let me tell you something if i can

pretend to understand quantum physics so

can you

so nowadays when we do research we don’t

actually take a notebook sit on a stone

and just look at the world pass by

we have a different approach we try to

implement everything in our laboratories

or what is actually even lazier approach

we try to implement everything in our

little computers

and this is kind of where we are stuck

at the moment because the calculations

we wanted to are not possible to be made

in our classical computers even in the

classical super computers

so now what is the concept of a computer

let’s start very basic

in any computer what we need to do is to

encode information in a system

in our computers we call this system a

bit and to be a little bit scientific a

bit is a binary system but it’s just a

technical world word to say

that is a system that can be in two

different states

usually we refer to it as zero or one

in reality this is just a little

transistor where we just apply a voltage

or apply no voltage at all and this is

pretty much our one or zero

but now what happens when quantum

mechanics wants to be like simulated in

a normal computer

well quantum mechanics is beautiful it’s

really gorgeous believe me but it’s also

a little bit complicated and this is

where our computers get a stack there

are many characteristics that make it

really beautiful and really complicated

but there are two that i think are most

important one of them is quantum

superposition which means that a quantum

particle is not in a defined state but

it can be in a superposition of two

different states

and on the other hand there is the

quantum uncertainty

which means that we don’t know the state

of the particle until we measure it

so okay let’s try to bring a little like

hand wavy example and see if we all

understand it

imagine i’m gonna toss a coin it’s still

up there in the air until we get to the

example so basically we have the coin

flipping around

and while it is in the air

the state can be somewhere between heads

and tails so we can say it is in a

superposition of heads and tails

and at the same time

while it is in the air

we don’t know

what the state is

however when we catch

the coin we are sort of like making a

measurement we are making an observation

and we are disrupting the system and at

the same time we are also defining the

state of the coin because it is no

longer in a superposition but it’s gonna

be in zero

or one which is the same heads and tails

right

so now i’ve said in normal computers we

just have a bit that can be in zero or

one but if we would have a quantum

computer we would have something that we

call quantum bit or what is the same a

qubit

in this case it’s not only in 0 or 1 but

it is in 0 and 1

at the same time

so now let’s imagine we have 20

particles 20 is a very small number

everybody can imagine 20 particles in a

box if you want

and now this seems kind of easy

but what happens if every single

particle can be in a superposition of

two different states

now you say okay it’s 20

two different states it cannot be that

bad

but actually if you want to consider the

entire system

and if you want to consider every single

possible combination

you would end up with more than a

million combinations

and this is exactly where quantum

computers are really beneficial and can

boost the computing power because our

qubits can naturally be in a

superposition of states which means that

they can naturally consider all the

possible combinations at once

so now let’s say i’ve convinced you and

find quantum computers are amazing but

how do we actually build them

so there are many different ways of

building quantum computers

and basically the main difference is the

system in which we encode the

information

so we can use photons we can use atoms

we can use superconducting circuits the

only thing that matters is that all

these systems can be in a superposition

of two different states zero and one

in my case i worked with photons

i love their properties they’re gorgeous

but they are also a pain to work with

as many photons as we get from the sun

or as many photons as we can create in a

laser system

these little bastards love bunching with

each other

all the time

so actually getting single photons one

at a time is one of the major challenges

that we have in photonic quantum

computing

believe it or not i spend my entire phd

trying to get single photons using

graphene and we did quite some good

steps forward but it’s still a long way

to go

so there are other systems as i said

another one would be atoms they have

their own advantages but they also have

their own disadvantages in the case of

atoms they get really distracted with

everything that is around them they like

interacting with everything all the

fields around them and because of that

it’s very difficult to get them isolated

in the case of superconducting circuits

they also have their own advantages but

they also like being really cold and

when i say really cold i’m talking

colder than outer space so this is

certainly a big challenge in a

laboratory

so what i’m trying to say is all the

systems have their advantages and

disadvantages

so basically it’s not clear who is going

to win this race of quantum computing

but of course like in any other

competition we need to define our

criteria how are you going to define who

the winner is

so in quantum computing we talk about

something that is called quantum

supremacy

and i thought how am i going to explain

quantum supremacy and i thought i’m just

going to show them what wikipedia says

because that’s what we all do don’t we

so this is what

wikipedia says in quantum computing

quantum supremacy is the goal of

demonstrating that a programmable

quantum device can solve a problem that

no classical computer

can solve in any feasible amount of time

and the funny part comes in a little

parenthesis that it’s right after and it

reads irrespective of the usefulness of

the problem

so actually this may not make any sense

to you but it totally does because

nowadays every single quantum computer

that is built is built with a specific

purpose with the specific purpose of

solving one and only one problem so

basically companies and

research institutions they’re just

looking for the problems that their

quantum computers are good at

then

they compare the performance of the

quantum computers with the classical

computers so whenever quantum computers

are ridiculously faster than classical

ones we are talking about quantum

supremacy

in 2019 google presented the first

quantum computer it was based on

superconducting circuits and they got up

to 53 cubits

and they claimed to solve one problem

within 200 seconds whereas the classical

counterpart would have taken 10

000 years

so a year later ibm actually claimed

that this could have been solved within

2.5 days

but this is not the point of my talk

and none of the companies is paying me

to advertise their products so i’m just

going to leave it there

the second and latest quantum computer

was presented by the university of

science and technology of china this was

this year

and this was based on photons they got

up to 76 cubits

they showed that they could compute a

problem within 200 seconds

whereas the classical computer would

have taken 2.5

billion years

so now if we really look at what they

were solving

without offending anyone here

it was kind of useless

but don’t get me wrong this is what

fundamental research is about

we make a little step forward

and it doesn’t look like we’re getting

anywhere but this step forward is so

important to eventually get to the

ultimate point

this is what research is about so we

shouldn’t focus on what’s the

applicability of this exact step but

like where is this taking us to

because i’m pretty sure

the first car was slower than bikes

and here we are nowadays with our fancy

cars that can go way faster than what

they’re allowed to

so

when i’m talking about the impact of

like quantum computers what is this

about what am i talking about

am i talking about i don’t know maybe

netflix not getting stuck when we’re in

the middle of the movie or tinder

getting a little bit more efficient

looking for matches

or maybe finally understanding the logic

behind the price of the flights

unfortunately this is not what quantum

computers are going to help us with

but there is something very very

important that they are going to help us

with and this is combinatorics

before i said that because quantum

particles our qubits can be naturally in

a superposition of states they’re very

good at looking at into different

combinations at once

so now imagine that you have a pile of

pieces

and they tell you you can put them

together in any way you want and this is

exactly what chemical and biological

engineering is about they have a bunch

of atoms the entire periodic table

actually and they can put them in any

way they want to get the drugs with the

properties that they’re looking for

so now if you imagine like the billions

and trillions of ways in which you can

put atoms together this is exactly where

our classical computers are crashing and

this is exactly where quantum computers

are gonna really boost the computational

power

another very important point when we

really consider different options

is when we have to make decisions that

consider many parameters at the same

time so you can have many combinations

at the same time and this is exactly

what artificial intelligence is about

us humans are very good at considering

the consequences of our acts

sometimes

but basically when we want to make our

robots our machines

smarter somehow we just want them to be

able to look at different parameters at

different options and give us the best

one because they have gone through all

of them

so hopefully i have convinced you that

quantum computing is amazing and that we

should totally go for it

the question is when is this going to

happen

so unfortunately

i have no idea

and it’s not because i didn’t pay

attention at university

it’s because nobody knows

it could be a decade two decades half a

century

to be honest your guess is as good as

mine

but there is something i know

and this is that it’s gonna happen

because in theory we know how to build a

quantum computer

the problem is that our technology is

classical it’s very big it’s very rough

and basically we have to adapt all our

machinery all our technology to be able

to deal with these little quantum

particles

so basically one could say that it is

just

an engineering problem

just

thank you