 Thank you! Thanks for showing up this morning. I have to start with a story. I'm impressed that the room is packed so I was playing in a rather unsuccessful heavy metal band for quite some years and I always dreamed about performing. Life can be very ironic. You start working on quantum computers and diamonds and people show up to your performance. Anyway, so I have to start with a little disclaimer and I mean that from the bottom of my heart. I'm a physicist or more precise I'm a material scientist and with that I have a strong background when it comes to materials and diamonds. My background is not so strong when it comes to the things you are interested in. Quantum algorithms and stuff. Although I will talk a little bit about that. Please be kind when it comes to the question and to answer part of this talk. Anyway, let's start. Whenever you take a look at the concepts of future computers of course it makes sense to take a look back on the computers that were there before and of course everyone of you know this diagram it's Moore's Law and this diagram it shows this is the time scale and it shows the numbers of transistors on a microchip and this diagram never fails to impress me because Moore, he wrote a paper actually on that and he claimed that the number of transistors will double every 24 month and he claimed that 1965 so back here down here at a time where we were only talking about few thousand transistors and this law is still true when it comes to the more modern computers where we have billions of transistors so that's quite impressive this vision that he had. How is that possible? How could we improve from a few thousand to two billions of transistors on a microchip? Well pretty straightforward and pretty easily by scaling down the size of the transistors of course. If we take a look this is again Moore's Law the same but now I show you the feature size the transistor size basically that you can find on such microchips and we started in the 70s with sizes of a few microns ten microns that would compare to your red blood cells to the size of your red blood cells and we're now down to 22 nanometers that's extremely small we're closing in to sizes like the diameter of your DNA which is like two nanometers thick or wide. How was that possible? Well it was possible by simply scaling you had a technology you had a method of producing these transistors and you slightly improved them and so you were able to reduce the feature size. Can we go on like this forever? Obviously no. I actually believe we already have seen the lowest limit that we can reach. There was a work group in 2012 I guess they produced a transistor made out of one single phosphorous atom in a silicon matrix. At least for me it's hard to believe that we can get any smaller than one single atom. I mean in the end you need to store the electron the charge carrier somewhere so I think we hit bottom already but the problem is not that we will at one time really I mean that was an experiment in a laboratory that is obviously not not a ready available market ship yet but still maybe we have seen the lowest limit that we can reach but nevertheless already going there to the lowest limits will make us face some problems and this problems will arise here when the feature size gets even slower because then we have to deal later than we have to deal with quantum effects and what that means I wanted to show you on the next slide with an easy picture again. Let's start with the German Autobahn for those of you who are not coming from Germany German Autobahn's are great because you can drive as fast as you want and that is not a problem as long as everybody stays on the lanes that is or I should say where you are supposed to be so if you are traveling in that direction you better stay on the right side of the German Autobahn if you are if you are somehow able to go over this barrier here in the middle and try to appear on this side you and your opposite car drivers will have some some problems same is true of course for microchips they are some or can be compared to Autobahn's we have these electrons the charge carriers running around somewhere here in these connectors and stuff transistors as long as they stay where we want them to be everything is fine but as soon as we come to really small sizes small scales something really strange is happening and this is a beautiful simulation of John Christophe Benoit showing you one electron this is this blurrish whitish thing moving towards a barrier a barrier that this electron cannot surpass and what you see here most of the electron is reflected or the electron seems to be reflected but what you also can see is that a small whitish blob is actually tunneling through this barrier where the electron is not supposed to tunnel through so you see when we come to small scales we are heading into problems because electrons are freely jumping around and that is not what we want so the question is if we cannot avoid quantum mechanics why don't we use it is there a way to use these effects and this is basically what I want to talk today about my presentation is is in two parts the first part is basic concepts of quantum mechanics but there won't be any equations so I will stick to pictures and nice metaphors and the part two will be a real realization of quantum computers how we try to do this with diamonds okay I promised you pictures so we start with this picture Manuel Neuer I love him dearly he made us world champion but I also envy him a bit because the game he's playing is fairly simple while I'm dealing with quantum mechanics and that's fairly not simple and this guy is learning earning much more money than me I don't have I would not even have a permanent position at a university but anyway let's let's take a look at classical soccer Manuel Neuer easy game he needs to information to play this easy game he needs to know where the ball is so he needs to know where is the position of the ball and he needs to know where is the ball going so the velocity that's what what physicists call it velocity of the ball so that means speed and direction so to information very easy game now we go to quantum soccer that's harder Manuel now needs to choose whether or not he wants to know the position then he don't know absolutely don't know where the ball is going or he chooses to know where the ball is going then he has no idea where the ball is you see the game is getting harder no words cut for us in the case of quantum soccer so being more precise now we can compare it now we can compare classical physics now with quantum physics as we have seen classical physics so if we're talking about balls it's perfectly fine that we know the position and the velocity of a particle that's that changes with with quantum quantum physics let's go back to the electron you see here this bluish reddish electron and we know let's say we know exactly the velocity of the particle we know where it is going and which speed then we don't know the the position of the electron actually so this is not how our physicists would draw it we like diagrams so we would do something like this here the x-axis is the the position of the electron the w here means the probability that the electron is actually at that point so it is very likely that it's somewhere here but there's still the chance that is right of there or left of there so it can be somewhere here with more or less probability Werner Heisenberg Germans physicist was working on that was a founder of this theory and this is Heisenberg's uncertainty principle that simply means the uncertainty of the position times the uncertainty of the momentum which is more or less the velocity is always bigger or equals to this constant this is simply a number this tells us something about nature and this is really interesting this is an intrinsic uncertainty which lies in nature so this is not because our microscopes are too bad or we are not looking close enough where the electron is or not fast enough this is an intrinsic uncertainty when it comes to small particles this is how nature is is behaving and that this is really contrite or you would not expect that I would say now with this simple principle we already can explain tunneling quantum tunneling the thing that we talked about already the electron coming close to a to a barrier to a energy barrier or let's say it's a wall and usually you would expect that a particle cannot go through the barrier but in fact now you see this diagram that that we physicists love and now you see the probability says it's very probable that the electron is on the left side of the barrier but there is still still a small probability that the electron is actually on the other side and this is the reason why a tunneling really happens and can be measured just because there is a mathematical probability that the particle is on the right side it really appears on the right side every once in a while and that this is what I already showed you with this beautiful beautiful animation and simulation by John Christophe Benoit yeah this is physicist humor told you Heisenberg this is actually a toilet in my faculty this is what physicists love about but anyway okay we talked about uncertainty uncertainty in position and velocities but this is not only true for positions and velocities but also for quantum states what what I mean with that let's talk about information so a classical bit you all know can be turned on turn off or in binary code it can be one or zero with quantum bits it's a little bit different and and we already talked about uncertainty and the same is true here for quantum bits if we talk about states of quantum bits you see here the the the quantum bits the qubit can also be one or zero but it can be everything in between that that's what physicists call a superposition these superpositions are really excuse my language fickle bitchers they only you only have a superposition when when you don't look at at the qubit so you don't you are not allowed to make any measurements as soon as you make a measurement you end up with a with a clear one or zero as a state for the qubit but as long as you don't look inside the box no information in no information out then you have the superposition this any state in between and you can actually work with this superposition so is that the same as when I would take a coin flip that coin catch it in front of 400 people and keep my hands cover covering up the the coin is that a superposition no it is not this this the state of my coin is described by yeah basically probability it's 50 50 either it is hats or either or it's tails and of course my ignorance because I haven't looked yet but the fate of the coin is already chosen that's quite philosophical okay the fate is chosen if I uncover it I see the result but the result was there before this is not true for superpositions of qubits as long as we haven't looked the fate of the qubit wasn't decided yet there is no record there there is no decision made yet and this is what makes makes qubits more powerful than that's one reason why why there lies power in the concept of quantum mechanics now let's talk about we already talked about qubits but the question you could ask now is of course what is a qubit so I mean in real life where where can I see one we start again with a classical bit comparison one and zero we could take this this spinning tops as a as an yet another picture easy either it is facing down and turning anti-clockwise or it is facing up and it's turning clockwise the same is true actually this is not true for qubits qubits are small particles and small particles like electrons protons photons they have a property that physicists call the quantum spin you should not make mix this spin with a quantum spin so actually the electron is not turning and spinning but still it's a nice picture so we use it but what you really can measure and see is that qubits have a small magnetic field so they have a north pole and a south pole and that's pretty that that comes handy because we we now can manipulate the state of the of the qubit if we take a rather strong magnetic field and we bring our in our our qubit it will very likely align in the position of the lowest energy that means of course the north pole of the of the magnet will face to the south and the south pole of our little qubit magnet will face to the north just like a compass needle of course you can open the compass and invest a little bit of energy and turn the compass needle in the other direction the same you can do here you can invest a little bit of energy and turn the needle the other way around this is a other state it's an higher energy state and we also use that in our qubit so you you can produce one and zero positions of your qubit and we come back to that later when I show you how we actually do this so then then we are at a point where we need to information so how probable is it that we find our qubit in a up-facing position and how probable is it that it will face down so two numbers and we can describe our qubit that's not very exciting I would say but it gets exciting when we start looking at more than one qubit because then is something very interesting happening let's start first again with two two-bit systems both spins are this year both down one down up up down up up and of course you know 1 1 2 2 0 0 so although the the system our two classical bit system can have four states we need two information to wholly describe the system you need two information what is the state of the first bit what is the state of the second bit that gets a little bit more complicated when we come to qubits and I spare you the and even more I spare me the mathematics behind it two qubit system it can be easy let's say this this case here both qubits facing up very easy two qubits facing down very easy but this here isn't isn't easy at all this is what physicists call entanglement in that state the one qubit is facing up the other one is facing down and the two qubit system the entangled qubit system is perfectly free in whatever direction it want to face we were already talking about that when I when I introduced the superposition but the same is here the entanglement now we have two qubits and they can face in in whatever direction they want so they are more or less perfectly free with one exception the one qubit is facing the one way the other one is facing the other way so you see you need more information to describe such a system in fact for two qubit system you may need for information so a d and this entanglement states b and c which comes out of rather complicated mathematical calculations for informations for two qubits but it's getting more extreme if we are talking about more than one or two bits versus two qubits you see here the classical bit system of course you already already know ten normal classical bits you need ten information and information for n bits but for qubits it's two to the power of n information so this system is getting rather complicated fast in fact if we would succeed in having 300 perfectly entangled qubits this number here two to the power of 300 is so big that you need more informations than we have than we have particles in the known universe to describe this system so you see the system is getting getting complicated but of course you can formulate it the other way around we have a complicated system so we can work on complicated problems and I touch back on that I guess on the next slide but first I have to show you one more thing concerning this strange nature of qubits again we start with a 8-bit register if you want to do calculations or if you want to rewrite the information in such a register you need steps process steps so that takes time so calculations rewriting of the register positions here takes takes you time in entangled systems and qubit superposition or entangled to qubit systems this looks a little bit different and I have already told you about that I told you about this entanglement that we have this two entangled qubits and that they are not independent of each other so if the one is facing the one direction the other one is facing in the other direction and that has a consequence in so far that if you manipulate one of those qubits you manipulate all of them immediately and that's of course there lies a real power because you you can in parallel do operations that you couldn't do in a classical computer are our quantum computers faster for every problem for all the problems well no they're not in fact for most of the problems they're actually slower if you would sit on your couch and stream a movie the quantum computer wouldn't have any advantage there are specific problems where quantum computers have the edge over classical computers and that's problems that I you are of course familiar with for example the the public key encryption protocol which basically is based on the fact that it's very very easy to take two integer numbers prime numbers and multiply them and everybody of you could do that within a minute I guess and tell me that the result is this large number here it is more complicated to do it the other way around if I would ask you what are the prime numbers that if multiplied give this number this is incredibly hard and so hard that that classical computers need thousands of years to do that and a quantum computer would only need some minutes to do that the reason is that this that a lot of calculations can be can be processed in parallel another or other non-radical problems are also problems that seems to be very suitable for quantum computers for example this year the phone book problem it is very easy for you if I ask you for the tele I give you a telephone book and ask you for the number of John Doe you could easily tell me the number if I just give you a number and you are supposed to find me the name from this phone book that will be rather hard and this again is a problem that can be solved with quantum computers more effectively in fact told you I'm not really strong in quantum algorithms but I show you at least the more famous algorithms that were found and they were actually found quite some years ago 1994 and 1996 the shore algorithms algorithm which is for integer factorization I talked about you see here if we take a typical example then you see that a classical computer would need 10 to the power of 19 steps while the quantum computer only needs around 90 steps and the same for the phone book 60 million entries the only strategy basically that a that a classical computer have is starting at a and go through till he finds the number no he's not starting with a but we started with a telephone number but he's starting with the first entry and go through the entries and at one time he by chance finds the right name to the number and the quantum computer is faster there with with a lot of less steps to find the right name to a number so I told you I'm not strong here but the message I want to send with this with this picture is this year the bottom line we have the algorithms so we need hardware now so give us the hardware and we're taking if we are okay we're taking or talking about the realization of a quantum computer there was a nice paper from a from a guy in from the University of Aachen divin chenzo he established the divin chenzo criteria for quantum computers so he said we want to realize quantum computers we need to realize or address these problems in for quantum computers and they are pretty obvious we need well-defined qubits of course we need qubits that are that we can trap that we keep at place and the next thing is we need to initialize them we need to give them a pure state either superposition or tell them be one or be zero we need quantum gates of course to do operations algorithms we need measurements to read out our qubits whether or not they are one or zero at the end of our calculation and we need long coherence times that needs that means those I told you already our superpositions our qubits there are fickle and they don't they act strange and randomly at times so we need qubits that are rather stable okay we need to address all of this in in the next slides but let's start with a short history of quantum computing here 2001 IBM showed the first real quantum computer and NMR computer nuclear magnetic resonance computer and they actually had a short algorithm running on it they're the so that they they used the short algorithm to do this factorization problem I showed you and the incredible number they were able to process was find the prime numbers of this number is anybody capable of doing that here right the gentleman said not not at this time but usually I would say you you are as good as a quantum computer when it's not that early on a on a congress day okay it's I give you the result it's three and five oh man it's I felt with my heavy metal band and now I prepared a good-looking presentation and all I need to do to impress you is giving you the prime numbers of I have I really have to rethink my my life after this Congress okay that was 2001 2005 2011 incremental improvements of the quantum computers 2011 he fight China for qubits giving you the number of other prime numbers of this number these are other in implementations of quantum computers as you know I will talk now about diamonds and quantum computers with diamonds but if you're interested in in in these implementations I strongly suggest if you haven't seen it the wonderful presentation let's build a quantum computer by Andreas Davis on this at this Congress rewatch it if you haven't seen it because it was really fascinating to see those concepts the problem oh I messed my joke you don't have okay what what I wanted to say is although Andreas realized a quantum computer here with these methods they have some kind of drawback all these implementations are rather complicated you need large lasers you need vacuum chambers you need strong electromagnetic fields to trap your qubits so this is nothing that that you would put on your office desk so this is what I call and please act surprised badass physics so of course physicists were looking for for alternatives and they were pretty surprised to find an alternative here in diamonds actually diamonds have extremely stable qubits at room temperature you don't even need to cool down your devices so this is something where scientists are really looking at and hoping for for improvement in the field of quantum computers because the diamond has such an incredible such incredible properties and I will tell you now why they are so incredible but actually we don't what we need is not we we don't need perfect diamonds but we need diamonds with small defects and and I like this this quote here from Colin Humphrey is a physicist crystals are like people it's the defects in them which tend to make them interesting like that very much because we we don't need perfect diamonds we need diamonds with specific defects in them this is a diamond lattice diamond is made out of carbon and what you see here is the special defect I'm talking about the NV center and the N stands for nitrogen and the V stands for vacancy or void so a missing carbon atoms so that that's what what you see here there's the nitrogen atom and there is the the void the missing the vacancy the missing carbon atom and these this structure in a diamond the NV center has remarkable properties they are a very excellent trap for electrons and we already talked about the that that electrons have a quantum spin so we have a trap for electrons the electron stays at the that position and it's rather stable for some reasons in in those qubits have a long coherence time at room temperature in diamond question now of course is let's start with this year we succeeded with the first point we have well-defined qubits now the question of course is can we measure them can we initialize them so first measuring them can we measure the state first an easy picture what physicists do when they want to measure something is they use laser so we shine a laser on this and these centers and we get a signal back and the signal is a little bit different to that that we shine in so we can distinguish between the laser that we put in and the light that comes out now we make that a little bit more okay that that's a picture of such a measurement what you see here these tiny these tiny points are actually single NV centers in our diamond crystals so how does that work I want to explain you that a little bit in more detail this is these are energy levels in our diamond we start with the ground state the electron is at the ground state if we now shoot with our laser light on it the electron will take some of the energy and jump up to the excited state it won't stay there for long it stays there for some milliseconds and jumps down then back again and what we see then here is fluorescence light light that we can measure and we get information from that now we play the same game again but we changed the game a little bit and we change it in the beginning let's start again with the electron on the energy ground level and we use some microwave pulses to give the electron a little bit of energy what happens then is the electron changes its spin you remember the picture I gave you the the compass needle the little magnet in a magnetic field if we invest some of the micro this microwave pulse is a little bit of energy and we turn and spin the the qubit in an up position so now we can with this microwave pulses initialize the qubit whether it should be zero or one and now we repeat the experiment from the left side and something impressive happens now again energy the electrons jumps up but because we are coming now from a from a spin up state something different happens it doesn't jump back down again and giving us the fluorescence light but now it jumps to an intermediate state stays there for a few milliseconds and then jumps back down to the ground level and the surprising thing about that is we don't see light or I should say we don't see the fluorescence light we are looking for so you see now we can initialize a state we can measure the state with our laser pulse we when we see light we know the electron came from the ground state if we don't see any light the electron came from the spin up state and what we also can do is if we choose the the microwave pulse right we can have a superposition so coming back to the to the diva diva Vincenzo criteria we have well-defined qubits in our diamond we have we are able to initialize to a pure state we have qubit specific measurements that is our laser so what we now need our quantum gates so we need to calculate or do operations with the quantum computers I show you an example not for diamond for another spin system because that's a little bit easier to explain on one slide but more or less I guess you you get the idea of how we are doing that with quantum with quantum gates so we're I show you the control not gate the C not gate for the few of us who don't know what that is we have a control bit this is the red one and we have a target bit the blue one if the control bit is zero nothing will happen to the target bit if we have if the control bit is one the the state of the target bit will be changed so if we start with a zero zero we end up with a zero zero zero one ends up with zero one one zero changes to one one and one one changes to one zero so how do we realize I mean in a classical computer you realize something like like gates by transistors how is that realized in a quantum computer well I show you this with an example with a model system of two coupled spins an electron and a proton and as you might know this is a hydrogen atom so we are doing now calculations with a hydrogen atom again we're talking energy levels here so we're starting with a lowest energy level would be the electron is down the proton is down lowest energy level corresponds to zero zero state electron down proton up zero one electron up proton down one zero and both spins up one one state you already heard how we choose the spin of the electron electron transition electron spins spin resonance that was simply the sorry that was simply the the microwave pulse that we are inducing and by that choosing the spin of the of the of the electron so now we can determine whether or not we have electron spin up and electron spin down and now we do something that that is called nuclear resonance NMR again electromagnetic pulse but a different energy and frequency and what we do here now is we choose wisely that the pulse has this energy here and then we have exactly the C not transition because only if the electron is spin up we will have a transition between those two states so there's pretty in your face actually okay the idea of doing operations with a single atom it might be not really be in your face but you see that how you actually do it is is rather simple you need one single pulse to do such a rather complicated logical gate or realize such a complicated gate of course I have to say you just need a single pulse if you have a good spin system that's of course what you need for something like this okay in principle I have shown you that how what that we can have well-defined qubits that we initialize to a pure state how quantum gates could work in such system and how we do qubit specific measurements but now I have started or the title of my presentation says that I'm working with diamond and we are trying to realize quantum computers in diamonds so that your question should be where is this guy getting his diamonds from are we mining them can we get them out of a mine this is an old mine an old diamond mine in Kimberley South Africa I like this picture very much and it is this mine is long closed like I think 1914 or something but this is believed to be the the largest hole that was ticked by bare hands so the people were actually getting the rubbish out there with their bare hands so this is the biggest hole could we take diamonds from diamond mines no because I have already told you that we need very specific diamonds we need them first to be very clear very perfect and then we induce very specific defects the NV centers that we already talked about so if we cannot find them in nature of course we make them by ourselves so what we use there is a microwave plasma chamber funny Lee it's not so different compared to the to the microwave ovens you have at home it has the same frequency it has the same power the only difference is that we we focus the the microwaves very precisely in the middle of our vacuum chamber and by that we can ignite a plasma in in the microwave plasma chamber and the plasma is actually that is what you see glowing here why can we make diamonds from a plasma well we use very specific gases we use methane as a carbon carrier CH4 you see here the carbon atom and and for hydrogen atoms and we use hydrogen because we need that for the chemistry and what happens then here in the plasma ball is that we break those molecules and we have then the CH3 radical and then we we do something tricky we offer those radicals a diamond surface we call that the diamond seed crystals we bring it close to the plasma and then more or less like legal playing by self-organization the this radical goes to the position on the diamond and continues to grow the lattice of the of the diamond so we can start with a rather dirty one and start growing our perfect crystals on top of it so does that really work I want to convince you that that works because this is a video of our plasma chamber you see this greenish plasma over the crystals here and these are our dirty seed crystals they ever heights of around half a millimeter and a diameter of around 10 millimeters so they're rather big and okay for the for this quantum computer application we don't need really thick diamonds but of course if you have a lab and you have a plasma chamber in there and you have seed crystals the first thing you do on a weekend where you don't have any other plans you grow large diamonds so that's nice that you clap your hands because I'm doing that from your tax money thank you okay this is a movie let's let's see how these diamonds are growing this is in the core unfortunately this is in the course of three days Friday evening till Monday evening those diamonds don't look very nicely you would now they are three millimeters tall so they're not now they're really yeah rather large sized diamonds perfectly single crystals in the middle and not so perfect and not good-looking in the in the outer edge here so what I did is I took a laser and cut out the perfect diamonds diamond and went to a jewelry shop and asked them because they really don't look like you couldn't impress anybody with them but I went to them and asked them if they can polish me the diamond like a real brilliant like the stones you would have in rings or amulets or something so the man there was suspicious because I had never seen such a stone so he asked me what material that is and I said that's diamond and then he said where do you have it from and I said I made it by myself we had issues I would say but I found somebody who was able to polish me the stones and they look like this they really look beautiful and whenever I want to impress a crowd like you I have a diamond self-made diamond in my trouser so if you want to take a look after the presentation just come up to me and take a look this is not really a perfect diamond but it's enough to impress people yeah right okay we have perfect diamonds now but the problem is and then we're coming to the end of my presentation the problem is we don't want perfect diamonds I told you we want NV centers in the diamonds so how are we getting now the NV centers precisely in our perfect diamond crystals well we take our iron guns something else that I buy from your tax money we take iron guns with we take the perfect crystal we take iron guns and we shoot irons nitrogen irons obviously on our crystals and what happens then is first a pretty mess so the nitrogen is in the crystal and then we do something that we call annealing we put the crystals at 700 degrees and some kind of oven and then something happens that the nitrogen brings mechanical stress in the crystals and the stress or you the crystal wants to relax the stress so what happens automatically actually is that that the v-centers the vacancies move to the nitrogen without us doing anything very professional with it so that is one way how we can produce the NV centers in our crystal the other one the other method is called delta doping I already showed you how we grow the diamond layer by layer and that is shown here at one specific time we bring in nitrogen into the process and then of course we deposit the nitrogen into our lattice now we have the nitrogen but no vacancies now we take an electron gun yet another thing I buy from your tax money we shoot in vacancies here do again the annealing step and we end up with NV centers yeah so now I'm really coming to the end well we have well I showed you that we have well-defined qubits we have we can initialize them I already told showed you that so we are able in principle to produce a diamond quantum computer how far are we with that what is the state of the art well it's in his infancy of course so we there was a two-bit qubit quantum computer realized Grover's algorithm was running on it and 95 okay and the calculation was pretty pretty right on the first try if we really would want to decode our codes in a reasonable time we need at least or I read an estimation that we need 4,000 qubits to do that and 4,000 perfectly entangled qubits is really not easy but still people are working on that based on Edward Snowden's documents you see that the NSA runs a project worth 80 million called penetrating hard targets I like the name of it very much to develop quantum computers so I already told you that I liked the presentation that's really my last sentence now the presentation of Andreas yesterday and his that was one remark that I want to repeat because I liked it so much if you ask me quantum computers are not there right now they're not effectively working but they will come because the technology already is there it is very likely that those concepts because you see they are there are rather complicated the knowledge about the quantum computers will be in the hands of governments or rich companies so it's very important that we keep an eye on the developments and what's possible and what's not possible and yeah to end on the positive side I will keep an eye on that for you with your tax money so before we start with the question and answer I have a podcast if you like the the way I talk about science the podcast is called me totally incorrect I do it with my PhD students who suffers very much under me so give him some love by downloading our podcast thanks nice plug is this on oh yeah it is nice plug okay so we have time for some Q&A there's four mics in this room to there to there also there's the ISC of course and we also if you're unable to get up for like an actual medical reason we have a backup all your angel to give you a mic so we'll just start with number two okay so thanks for the talk my question is can you realize entanglement between different NV centers which I believe would be necessary to do more than two bit quantum computing yeah first before I answer the question you're the first audience who's not asking about the diamonds and whether or not I'm rich because I'm producing permanently diamonds but I appreciate that there was there yes there were realizations of entanglement of two qubits in diamonds and more than two qubits in diamonds but what what you're talking about is exactly the problem that we are having and what we are doing research right now on because the there are a lot of parameters that influence the stability of those qubits in a quantum diamond computer for example the distance between the qubits is a very important factor the distance of the the qubits to the surface of the diamond is a very important factor the the the chemistry that is that is on top of the diamond crystal even makes a difference so that's actually the problems we are working on yeah thanks does the internet have a question now internet still asleep yes the internet has a lot of questions at first I have to apologize for being imprecise you spoke about the qubit specific measurement the part of the talk the question is what happens with the energy if the qubit does not drop to the to the lowest layer I think you mean when when we're starting with the queue with the qubit up and yeah I was pretending that there is no energy emitted but that's of course not true the energy has to go somewhere but it is in a different frequency so if we are just measuring the fluorescence light or we are just looking at the fluorescence light we want to see then we don't in that frequency we don't see a light but of course the the energy is going somewhere else so there there will be light be transmitted but in another frequency so you don't see it we don't see it and does this effect happen my multiple times yes of course yeah you can initialize your system again and start the process over again and that is actually what's what's being done you you repeatedly initialize your system measure it and do that thousands and millions of times again and again yes and the internet is also interested if it happens if it happens from alone or does the qubit drop by not being measured yes the qubit would also drop without being measured that that's one again one problem that we need to realize we want to have stable qubits that that keep their position as long as possible but every once in a while of course the qubit will change by chance so this is exactly what you need to control you need to have stable systems that stay in the position that you want them to be for as long as possible so but you're absolutely right and that makes it hard at this time to realize quantum computers to have them stable over the time yes okay thank you I'm just a quick reminder if you're leaving now please be aware that there's a camera right there so if you stand up in front of the camera nobody's happy so okay microphone number one please well first of all thanks for spending our tax money in a really reasonable and totally cool way so I was wondering if we assume agencies with basically unlimited funding and highly compartmentalized information do you see any practical risk that they in air quotes have the technology at scale and we simply do not know about it yeah I'm asked this question I'm asked quite a lot and of course it's hard for me to to to really give an estimation about that usually I would say I'm I'm pretty I have an eye on the on the on the developments that that happen in in in science or in my field at least and what you usually see is that you you have publications on one topic and when it's really getting dangerous those publications will drop and you will not hear anymore about the findings in that field and people the experts that are working on in this fields are vanishing so I would say optimistically I don't think that they are much further but I cannot say maybe they are further than the publications suggest yeah with with Stuxnet we've seen that academia has said some people have said that what was in Stuxnet cryptographically was years or even decades ahead of what academia knew about so yeah what that makes a little pessimistic view on the works I'm doing every day but yeah I got I hope you are not right but I cannot yeah thank you thank you so if there's no talk by Nicholas next year you know what happened I'm either really rich then or turn to the dark side yeah right the chances are very really low but Mike number three please hello do you think there's a big difference between building a quantum computer with a few hundred bytes or a few thousand bytes because that's an important question whether we should use elliptic curves and do you have any estimation how long it will take to till we have a practical quantum computer that's really tough questions because we're we're this is really fundamental science right now and we are really struggling with a few qubits having them entangled for a longer period of time or for a time that's enough to do calculations with that and you see we're like yeah this this is really not like Moore's law that we could say now we're at 10 and so we just calculate and say in 20 years we have the thousands that you need there might be there is so much fundamental physics to be done there on material science I couldn't even tell you if a real working diamond or a quantum computer that there will be quantum computers that's for sure but will that be realized in diamonds I cannot tell you because there are so many problems just what you said if you if you're starting with a few quantum bits they they disturb themselves and so it's getting increasingly difficult if you increase starting with four qubits going to eight or 16 so that's really hard I I don't dare to give you any numbers if that will be possible in the future or even when it will be possible so I'm sorry can you say something like if it is much more difficult to build four thousand compared to four hundred bits that's really important for the cryptographic implications since we haven't realized four hundred I'm not sure we find methods that that will scale that's that's the question if we find methods to produce I mean we are really struggling to bring in precisely four or eight in a specific distance from each other so yes when we have the methods to make it with eight maybe it's possible to make it with four hundred and then we are at four thousand but I see no technology now that is scale scalable to do that so right now I don't know how thank you Mike number one please you really often talked about the the the state of the the quantum bits in the diamond how long of time period you're talking about they stay stable some milliseconds so I think from the the one publication that I showed they stated something like two milliseconds but that's enough to do some calculations that that would be enough yeah and then again like the question before we can initialize them again and do the calculation again but that's again something that we are working on this is to improve that time to make more calculations after the initialization how about the internet yes one question is or you talked a lot about our tax money do you publish in open access yes I I tried to yeah my last paper not on diamonds but on graphene was published open access so I'm I I really suffer from the publication system I feel your pain so I I think it's really it's a shame that that you are not able to access the the publications the funny thing is not even I am able to access all of my publications that I published some years ago because we cancelled the subscription of the journal so I cannot access my own papers and that's absolutely bullshit so this the whole system is fucked up but but to be fair the European Union is changing the system a little bit now when I'm funded by European money and also German money from from funding agency they they expect that the science that I do will be published open access so there is something going on in that field so that that's not so pessimistic or it's getting better there at least Mike number two please you said you would watch kind of watch the market for us I've got a question about D-Wave do they have a quantum computer that conforms to your criteria I mean D-Wave is a company and so they are not publishing what they have so it's it's really a little bit difficult to get real hard facts on that but as as as from from everything I know or I see they have a different realization of the of the quantum computer they have something that is called adiabatic quantum computer the real difference there is that they are not working with as far as I understand it with a really entangled qubit so they are not they haven't realized the the power or they haven't set free the power of a real quantum computer as I said it's really hard to get information there but from everything I have read this is not a pure quantum computer that I have suggested today here but this is of course something I mean this is a big company there are big companies behind that and there is money and they are at least working on the realization of the of the principle so this is what I wanted to say with the last sentence so we need to be aware of that that people are working on that and people with lots of money so they they are not there yet this is not a quantum computer I'm talking about and the quantum computer that will crack all our passwords but people are working on that mic number three please you presented two different methods how you get the nitrogen and the gaps in the diamonds and I well in the pictures we saw different orientations of the nitrogen and the gaps and I was wondering if it makes a difference and if so if you can influence what is the orientation it makes no difference and we have we don't have influence like like you saw it's it's more like a random process so we shoot the ions in there or incorporate the nitrogen and then make this tempering step and this is a self-organizing process this is actually the this is the hard thing or we are working on that so that I'm funded by this Mercato research funding agency and that is the the task that we are working on right now is how how are we able to put the NV centers at a specific positions where we want to have them but that is not orientation but position and how can we yeah how is that influencing the performance of the NV centers in our diamond but yeah in the end there is not when it comes to the orientation or this annealing step there is no control if you want like that I mean we have some process control of of course temperature and yeah basically temperature to to make this more efficiently or let the vacancy move faster and and give them more energy to move but that's all yeah thank you okay we are unfortunately out of time so I have to officially shut this down but he and like Nicholas is still here so if you have questions just come up thank you please use the prompt exit