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