 Hello and welcome to NewsClick today in Talking Science and Tech. We are joined by Prabhupi Prakash. So Prabhupi, we see that in the last few days, for the past couple of weeks, China has made varied tech advancements. We saw that the Chinese moon lander just came back and it returned with the first moon samples in 44 years. Then Chinese scientists also fired up their artificial sun nuclear fusion reactor successfully for the first time. But what we want to talk about today is the Chinese quantum computer which has achieved quantum supremacy becoming only the second computer ever to do so. But before we get into how it was done, can you explain to our viewers what quantum supremacy is? Why is this so significant? Without getting into what is a quantum computer and we'll do that just a little, what it is, the quantum supremacy means that a computer based on quantum principles can do calculations which are classical computer, the computer that we all know which is what we used in our lives that cannot do. So this is the quantum supremacy issue that it can calculate in a finite time something which will take a classical computer much longer. Then the what is a quantum computer? Of course, becomes the second issue therefore that unlike classical computers which have only two states, zero or one, it's either a bit is on or off and that's the basis of our computing. As you know, it's a series of zeros and ones we use and they can be converted into the numbers that we want at the end of it. But the computer really has every bit of it has two states so that's a bistable state so to say. So that's why we have binary arithmetic inside the computer while what we write programs can use our numbers but it converts for the computer everything into a binary system. Quantum computer works on the basis of what are called qubits, quantum bits which means that in the same bit can have multiple states. It can have a combination of zero one as it were and this is difficult for us to understand. What do I mean by a bit being in two states or a combination of two states? So this is something that comes from quantum mechanics and we're not going to try and understand it today. All we need to know is that it the same bit can exist in multiple states simultaneously and therefore the quantum computer as you pile up qubits is capable of computing much larger numbers and much larger combinations than what a classical computer can do. Therefore certain kind of maths it can do which a classical computer cannot do and therefore it would solve a certain class of problems that classical computers would take eons to solve. That's the basis of this whole exercise and it really comes from the fundamentals of quantum physics that there are multiple states in which a certain bit can be if it is using quantum principles and therefore the combinatorial power and this really works out if there are combinatorial problems then the combinatorial power of such bits means it can crack much larger problems and much lesser times than what a classical computer do. Therefore a whole bunch of computational problems may be open to quantum computers. Did Google do something which made a did it solve a problem which can't be solved otherwise? Well again this led to a big debate and IBM said they had actually said that the IBM supercomputer will do this in x number of years while we are able to do it in 200 seconds. IBM said you know that's not that much of a difference. We can also do it pretty fast. We have to pre-compute a whole bunch of stuff put it on a hard disk a gigantic hard disk and then we can calculate quite fast. Now the issue here is not whether Google achieved a overwhelming defeat of the IBM supercomputer. It is that the specifically how you solve a problem can be accelerated also by a classical computer but the point is that the fact that IBM had to do all these contortions to prove that the Google computer wasn't really that superior means that obviously it had an edge over straightforward calculations we do today. When we come to the Chinese example the why they should repeat something which Google had already shown namely quantum supremacy but by itself have not been that important. But I think the importance of this is not that it has demonstrated a second time because don't forget IBM still contests Google's argument that they have achieved quantum supremacy but I think the important part is apart from quantum supremacy it also shows that you can use photons as qubits and that's a huge new ballgame opening up for the world. So I think the important part of this is two four one that you can use photons in qubits and you can that has been done earlier with small number of photons but you can do it with a large number of photons in this particular case it's 50 to 100 photons were used again there is a range because there is a photon escape and so on so I'm not I don't understand it well neither am I going to go into those details but I think the important part of it suddenly it has been shown that one approach is using certain kinds of materials and also near zero temperatures which is what Google's quantum computer was based on and the other possibility is use mirrors and use light to create photonic quantum computers and that provides a new basis of calculation and it can be scaled up to the extent of 50 to 100 photons as the Chinese paper in science talks about and therefore a class of calculation which cannot be done by classical computers becomes open to it of course there is one difference between the Google psychomore computer and the Chinese example that has been presented to us which is the psychomore is a more programmable quantum computer this computer has been created essentially for the problem the boson sampling problem so in that sense it's one of a kind competition is doing and unless there are some more technological advances which could happen because it's shown theoretically they could happen it cannot become a universal quantum computer but let's face it even the Google quantum computer hasn't really been used as a general purpose quantum computer because there are hard problems we still need to solve which is what is called error correction and so on so these are all proof of concept and I think the Chinese example using for photons is a proof of concept that protons can be used as qubits and if more advances take place they can also then be used as programmable quantum computers but let's face it whether it is Google whether it is the Chinese case that we are talking about or other quantum computers which are in the offing all of them are at the moment maybe 10 15 20 years away from actual implementation of a universal computer using quantum principles so I think that this is there but it is exciting times because we have shown that something which was proposed by Feynman as a could be used as computers within about 30 years 35 years is now actually being developed people are spending huge amounts of money on it and it seems to be able to solve the class of problems which classical computers may not be able to solve. So then what can we do with these problems that quantum computers can solve what does this mean for us in the regular life what applications do we get from this you know because as you said the Chinese computer was only able to solve one it was made to solve a particular kind of problem and we're far from universal general computer so what sort of problems do we want these computers to solve. So if we are able to do programmable quantum computers which I think now that gave another 5 10 years we should be able to do both because of advance in materials that will take place the kind of technologies we are dealing with that will take place all of this is a function of the amount of money we are able to put on it and if it has functions obviously people will put in the money so it really depends on what is the expectation from this. So there are two sorts of applications one I will call the more benevolent the humanitarian kind advancing science advancing everyday technology that is regarding a set of calculations which today our computers cannot do for instance the simple thing which is called protein folding. Now protein folding is very important if you want to do biotechnology you want to develop new materials you want to see its properties it could also be in drug development so all of this is something that we cannot do with classical computers protein folding nature does in a couple of seconds phones the protein even shorter but a classical computer would take you know a thousand years 500 years 200 years to solve such a problem of course Google has made some advances using heuristics using past information and they are able to do using artificial intelligence as it is called they have been able to predict protein folding much better than what we thought was possible a few years back but nevertheless it's something which is not easy to do in a classical computer. So these are one class of problems which have immediate implications then of course the other sets of issues which are there is the fact that you can break code and if you break code therefore all the encryption algorithms that we use would then be obsolete so that of course is something which the militaries of the world are very interested in because you could do that they could crack enemies code on the even the friends code because you're always trying to steal other stuff from them as well. So in this world of gray and black white world of spying and surveillance this would be a huge boom so of course that is that can be weaponized too so that is of course the second attraction and the converse of that you could do quantum information exchange you could use the principles of this kind also to communicate with each other with yourselves I mean your different entities different places which could also provide unbreakable codes so there is a military application to it but the civilian administration is really because we are now getting into the area of biotechnology in a very big way and I think the future of the technology lies today in biotechnology and competitions therefore quantum computers can provide really in the future huge advances in this direction because that's something that we cannot obviously do with classical computers and therefore we do most of this stuff empirically. So finally Praveen the Chinese computer which we were just discussing it's called Zhuzan can you tell us what this means why has it been named so? You know that's a very interesting history that we are talking about this is an ancient Chinese text I think it was found or it has been dated what copies we have found is second century AD and it may go back much further in terms of unwritten copies which may not be available today now that is basically mathematics in nine chapters that's really what the title is the interesting part is it has a different approach to mathematics and what comes in the Greek geometrical approach which was really problem solving state axioms and then you try to solve and the restrictions you solve it only with straight edge and a compass so the various various kinds of restrictions put on that it tried to make mathematics as a branch of logic almost while when you come to most other places in the world the approach has been problem solving how do you solve problems and Zhuzan not only provides a set of solutions how to solve problems in a general way but it was considered in advance of a lot of the mathematics that we saw in rest of the world not all but some of it was in advance so some of the principles they talked about are discovered relatively much later but the interesting part of it it also has proved for instance the Pythagoras theorem has also a proof in this particular example in China it's I think called the Gogu theorem so that is also there and even the proof is described so it's not that they were not aware that you know mathematics can be done through proof it can be done through logic and proof but their approach was how to solve problems and this therefore summarizes generalized principles of solving problems that means also recognizing what are the class of problems that we have now this is something which is not unique to the Chinese the other civilizations which also did that also we have the the recently the Bhakshali manuscripts which were not mathematical manuscripts there were more manuscripts which are used by essentially business trade trading people who went on trade had to calculate various things so there were alternative approaches to mathematics and it's another matter that the Greek one has been sort of elevated to a much higher pedestal because the Europeans would like to believe that they were superior and the superiority comes because the Greeks did something so interestingly the Greeks they're talking about half of them were actually the Anatolian plateau which is really then Asia modern day Turkey but the point is civilizational terms that's what they would like to believe that that's where the west has come from therefore the focus on the western sources Du Zhang in that sense is also a way of talking that it is not just the west that has done all this that China and other civilizations in this case China because that's why they have named their computer Du Zhang and I think the is what they're trying to say hey you know others have also done mathematics you know it's not only the west not only the Greeks and I think that's why they have also named this after this famous mathematical text thank you for talking to us today on this issue that's all the time we have keep watching this