Can we make quantum technology work? | Leo Kouwenhoven | TEDxAmsterdam

good morning everybody does anybody recognize the picture behind me what is it that computer and it was in fact a mechanical computer the computer that was used by Alan Turing which helped to end the Second World War what is interesting is that here the wheels are turned and by registering clicks and no clicks they could break encrypted messages so it's a mechanical motion that actually can do some calculations for us now we use of course electronic computers where electrical signals and code for our bits zeros and ones but clicks or no clicks or zeros and ones actually is the same principle for encoding information no difference between the Turing machine and our computers what is amazing is that and what happened in the last 50 60 years is that this machine now fits around your wrist and it sells as a SmartWatch the same computing power anybody else who has a SmartWatch here I see a few uh-huh so you fell for the same commercial as I did I guess but what it's smaller and it's you know you see that the revolution in making things smaller is very visible but what is maybe even more amazing is that the underlying principles of the Turing machine are clicks and all clicks and in my SmartWatch it's still the same that has not changed clicks or no clicks zeros or ones now some time ago a very interesting new idea started to become popular and there's not really a single inventor and in fact it is not really an invention it's rather a change of perspective and the idea is that nature also calculates for instance when light hits a green leaf it induces all kinds of chemistry which at the end of the chemistry reaction it produces ox among other things and the process in between the input light and the output oxygen can be viewed as a calculation now why this is an interesting change of perspective is because nature actually calculates a lot faster and a lot smarter than our computers do the key ingredient that nature uses is in fact quantum mechanics and the beautiful thing of quantum mechanics is that you don't have to be a 0 or a 1 you can be 0 and 1 at the same time and this option of being 0 and 1 at the same time is used in nature zero ones at the same time that they sound acceptable but clicks and no clicks at the same time that is absurd nevertheless people like me we've started to use these principles of quantum mechanics to build a new very powerful computer it's called a quantum computer and how the quantum computer works and why it is actually good that's going to be my story today and you first tell you a little bit about myself I grew up in a small town in the Netherlands on a farm and I was actually doing okay in high school and I was allowed to go to university but the only people in my town that I knew who had a university degree was our town veterinarian and our priest now becoming a priest was not an option for me so I was going to be come a vet however and unfortunately my university had no entrance exam but instead a lottery which I lost so I ended up at my second choice which was physics but my roots remain III as a farmer's son I keep this pragmatic approach and nowadays as a professor if I hear some of my colleagues you know make very profound theoretical predictions now I think wow that sounds profound can we actually do something useful with it and that is also my my attitude to watch quantum mechanics and quantum mechanics is certainly among the most profound scientific ideas that we have around people like Bohr and Einstein now discovered the deeper principles of quantum mechanics about a hundred years ago and those principles of complex are absurd for us humans but not for small particles like electrons so what a small particle like an electron can do is for instance not be confined to one single point in space now it can actually occupy different points in space at the same time now how that is possible is actually very impossible to explain in words in our language the best thing we can do is just accept that was what is absurd for us is OK for small particles like electrons and so think about this for a moment because it's actually very essential for my story that a single particle the single object can actually be at different locations at the same time we call this superposition superposition and when you accept superposition then you can actually also understand things like chemistry a friends is a very simple example the oxygen molecule we draw it like two oxygen atoms that are held together by these horizontal lines in the oxygen molecule now what do these horizontal lines actually stand for well they share an electron but this electron does not sit still in the middle between these two atoms no it actually divides itself up goes into a superposition and occupies the space around each of these two oxygen atoms and since these two parts these two parts of the same sing electron doesn't want to be too separated it actually keeps the oxygen atoms together and so it's actually superposition that binds atoms in molecules and since it's actually actually our our body consists out of molecules so without superposition you know our body would fall apart and without superposition all our molecules would fall apart in loose atoms so superposition is a good thing and you should like it on Facebook so since Einstein and Bohr and actually also other genius scientists developed the principles of quantum mechanics we've been using mostly formulas formulas to describe nature as it is given to us but now 100 years later it's actually time for something new we now view nature as an information processor instead of formulas we use this symbol to describe that there is an information flow in nature and we no longer study nature as it is given to us we actually have started to design and construct actual subprogram the machines that we make ourselves and study how our own designed machines can actually solve quantum problems so my job has become to make qubits instead of a farmer instead of that I have become a qubit maker or a superposition maker and I want to illustrate that with electrons in boxes what you see here in the upper row are two boxes and one electron in our world that electron has to choose it can sit in the left or in the right box in an information description of the same thing what we say is that in the upper case when the electrons in the left box I call it a bit zero or if it's in the right box I call it a bit one and this is actually how we encode information in our normal computers that's a bit zero and a bit one now the special thing that we do in our lab in Delft is that we can do also super positions so we can take a single electron and put it in both boxes at the same time the kind of similars the oxygen at molecule but now we've boxes that we have made ourselves and we can also control and program so when the electron is involved boxes at the same time in an information description we say the system is in a qubit state and the qubit is in a superposition of a bit zero and a bit one at the same time so then codes for that information at the same time now if we have these qubits we've made actually a little animation to illustrate how it can be used to speed up calculations and you see here a labyrinth and if we put a classical electrons into this library then the way electrons actually solve classically this problem to find the exit of the labyrinth is what we would do we try path by path and every time we find you know it's not a solution we try again so sequentially we go through the system until we found the exit but as when we find the exit we know we have the right solution quantum electron would split itself up and in parallel in a superposition take all the paths at the same time and also reaching the exit but now a lot faster and there is the magic of a quantum computer all these actions all these different possibilities can be checked in a massive parallel calculation and find the answer in a single step that speeds up the calculation so what would we do if we have a quantum computer what kind of do we actually have good problems to feed such a super powerful computer well to answer this question let's zoom out a little bit and ask ourselves what are actually the big challenges that we face on earth the big problem so that the many big problems but let's focus on our natural resources here we are we're spoiling energy we're wasting materials our climate is changing too fast and many people on earth don't get the right medicine and these are very big problems that somehow we have to solve and we have to solve it rather soon at least within the next few decades to solve those problems we need radically new tools and no one doubts that help from a supercomputer will be of vital importance to actually solve these problems and that's what the use of the quantum computer can come in now universities I'm working at a university have started to develop the fundamentals of quantum computers since two decades or so and in the last few years also some of the bigger global IT companies have joined this effort and when companies join and invest money they actually have some specific ideas for the purpose they want to use the quantum computer for and has made a little list of what they say will be the applications of a quantum computer so it's a list starting with electrical cables with zero loss of energy drug development by solving quantum chemistry problems predicting material properties for electronics and energy storage machine learning optimization problems for robotics handling big data for sequencing genomes and airplane design but this list is of course by far not complete these are just a few examples and it is impossible to predict you know what you can do in a new technology so we started a Institute a new Institute in Delft to actually work in a focused way on developing this quantum computer it's called Q Tech and in this Institute we make the hardware so by using nanotechnology and cleanroom fabrication we make electronic chips with a whole bunch of qubits that we can program and by program these chips we can learn the how quantum systems solve problems now with we do that together with electrical engineers and we make these chips that you see here in the last shot and this is an electronic chip that has a whole bunch of qubits on it and nowadays we can make between five and ten cubits on the chip and program and control it we think that we need another 10 years or so to make circuits that are big enough to really solve you know relevant problems and have an illustration how it will go how it will develop from there so suppose that we know we take for instance the biggest supercomputer that we have nowadays in the world it's in the u.s. it's called the Titan and this computer is actually as big as this concert hall now if I want to make this computer 2 times faster what I have to do is I have to make it 2 times bigger two concerts all if this were a quantum computer it's the same starting point then in order to make it 2 times faster I only have to add one cubit to the to the supercomputer and one cubit is very tiny you can't even see by your by the naked eye so every time you're adding a qubit to the corne computer it becomes 2 times faster and that is because the computational power of a quantum computer scales as an exponential it's 2 to the power the number of qubits now Exponential's are difficult to understand but let me try to illustrate it with a number example and I have to go off stage for this example actually because if I I'm a linear machine if I start to give handshakes to everybody in the audience then you know it's a linear process and I need now ten steps in fact to give ten handshakes and I need two four four more I do this linear I'm a classical machine suppose I could go into a superposition then in ten steps I actually can shake two to the power 10 that is a thousand twenty-four hands so in the same sequence I would have given everybody here in the concert hall a handshake and that is the difference between a classical computer or small section and a quantum computer everybody in the concert hall so we're not talking here about some incremental improvement of computing speed this is really a revolution in information technology it's a game-changer now funny enough and lucky enough its nature it actually helps us to develop this quantum computer and that brings me back to my leaf in the photosynthesis reaction that happens in between the light input where it actually releases electrons in the leaf that have to find a way from their starting point to some specific end point where they can release the oxygen and in between there are many different paths for the electron to take to go to the site where it can release the oxygen luckily the electron can go into a superposition and as in the liberian problem can find the end state very quickly and produce you know the oxygen for us very efficiently so our bodies are kept together the brief oxygen or because of superposition and that brings me to my take-home message nature uses quantum mechanics to compute and we quantum engineers have start to begin to make programmable quantum computers and help solve some of our earth problems so I hope that with a common computer that we will live better lives and be more careful with our resources on earth thank you very much thank you

Channel: TEDx Talks

Views: 508,449

Rating: 4.8114619 out of 5

Keywords: TEDxTalks, English, Netherlands, Science (hard), Computers, Nanoscale, Nature, Physics, Technology

Id: aUuaWVHhx-U

Length: 18min 20sec (1100 seconds)

Published: Sun Nov 29 2015