© RIA Novastation martinis, quantum chief technologist at Google© RIA Novosti

John martinis, quantum is a leading technologist of Google, spoke about the creation in his laboratory heavy duty quantum computer, which would be impossible to check by conventional computers, and shares his thoughts on whether such machines threaten the military and state secrets.

This week, Moscow hosted the international conference on quantum technologies, ICQT 2017, organized by the Russian quantum center. Leading physicists of the world, engaged in the development of quantum computers, quantum cryptography technologies and systems for secure transmission of data, presented in the framework of the major discoveries and achievements in these areas in recent years.

Professor martinis said at the conference today about how Google and members of his lab are moving toward so-called «quantum supremacy» – create a computational system based on quantum bits, qubits, which would be impossible to calculate with ordinary computer for a time less than the lifetime of the Universe.

— In fact, such wording at the moment is a small but exaggerated. In my opinion, full-fledged quantum computer needs not only to work but to be of some practical use. In this sense, we are not yet ready to solve this problem.

On the other hand, now we are preparing and are already working on creating a really powerful computer system. First, we would like to solve the problem of «quantum supremacy» by proving that quantum computers can actually solve «unsolvable» problems, and then we start to think about how you can use it in practice.

These experiments will, we hope, will help us to demonstrate the power of quantum computing systems and their ability to get the right answers to very difficult questions. If we succeed, then we will have the opportunity for a second to get the answers to those tasks that are the most powerful conventional supercomputers decide over days or weeks.

**— How are you going to test a similar computer, if it work it will be impossible to calculate with classical computing systems?**

— Of course, from a formal point of view, you cannot do this, but such checks do not have to be implemented through a full understanding of what is happening inside a quantum computer.

We just need to make sure that parallel computing within the computer that do occur, and that its capacity correctly increases as increasing the number of qubits.

If computing power and all the resources in our computer will grow exponentially as you add new qubits, then the time of receipt of the correct answer will decline the same way. This will show that we have achieved «quantum supremacy».

Our hybrid approach is not a device, but a special algorithm, which allows us to combine a large number of qubits required to achieve a «quantum supremacy» and to control their behavior, greatly complicating the device of the whole system.

Why it seems to me that superconductors would win this race? In recent years superconducting qubits suddenly began to work well, we have learned very well to produce them and to unite with each other. We have managed to combine the nine qubits, and we have good reason to believe that their number can be increased significantly in future.

Right now in our labs tested 22-Cubana machine, and now we can say that it works and that in principle we could move on. Today we can say that we learned how to create a working quantum computers, and that in itself is a huge achievement and step forward.

**— What are the most unexpected problems can quantum computers solve?**

— This question, in fact, is the next logical step in the development of quantum computers once we reach the «quantum supremacy». In recent times we often say that quantum computers most of all will help us in the study of quantum processes in chemistry.

Here we are actually back to what he was talking about Richard Feynman, father of quantum computing systems – we create quantum computers to solve complicated quantum problem, and describe the behavior of complex quantum systems.

This is today – according to current statistics, approximately 30-40% of the capacity of modern supercomputers is spent on the solution of problems of quantum chemistry and the simulation of processes in the quantum world.

Interestingly, the minimum level of performance of the quantum computer and the number of qubits needed to solve such tasks has declined markedly in recent years. For example, recently our colleagues-theorists from Google published an article in which they managed once again to reduce the number of qubits and the complexity of linking their elements that has brought us close to the solution of these tasks today. The gap still exists, but it no longer looks so insurmountable a few years ago.

**— Many of your colleagues claim that a universal quantum computer will be created in the next 10 years, and something like they were talking another 10 and 15 years ago. How do we need such cars and whether their creation at all?**

— I kind of predictions always seem to be fun – their authors are usually theorists, and my team and I have to build such a machine and solve a lot of complicated tasks. We still only know how to create something similar to a universal computer, but not the full version. It was one of the reasons why I started working at Google.

Of course, today we have reached a point of development when we just have to try to build a universal computing machine, and now we and our colleagues at Google are making a lot of efforts and allocate huge amount of resources to this task.

On the other hand, the solution of many practically important tasks requires algorithms and error-correcting systems, and more simple quantum computing system can create today. The problem is that we don’t know if one or the other «analog» algorithm to work in each case because of the lack of rigorous evidence, available in the «world» of universal computing machines.

In fact, we here repeat the history of the development of computer technology in General – at the dawn of the computer era there were a large number of heuristic algorithms that do not have proof, but working with them helped to move computing forward.

Similarly, analog computers appeared much earlier than their digital counterparts, and they are very long and used to address the serious challenges before appeared in modern processors with enormous computational capacity. Something similar, I believe, will happen in our experiments and in the quantum world in General.

**In the last two years, your colleagues have started to think about the fact that one particle can contain not one but two or even three of a qubit. Will this approach to accelerate the establishment of universal quantum machines?**

— In fact, our logical qubits and the devices that we are manufacturing at their base, use the third energy level to his work, and therefore we can say that they actually are qubits, and kutrite. And overall, it’s a very good approach for the creation of quantum computer systems from an engineering point of view.© Photo : Guilherme Tosi & Arne Laucht/UNSWФизики «dressed» quantum light computer in a «straitjacket»

There are other proposals on the use of multidimensional spaces to encode information, but until we have a theory that would describe the behavior of such qubits.

This theory is needed in order that we may find and correct errors that occur during operation of a universal quantum computer. Without such a system of error correction, we cannot use them in principle. Of course, these ideas are interesting, but it seems to me that a full-fledged computer on the basis of such multilevel systems will be very difficult to create.

**— IBM and other IT companies plan to create a «quantum cloud» and selling time on quantum computers for any users on the network. Given that a quantum computer crack RSA and other cryptographic systems do we use the government to impose severe restrictions on the sale of such services?**

— Actually, it started already, company D-Wave already sells computing power of their computing devices to customers, and IBM is also already offers such services. It seems to us that this is the right approach – it saves customers from having to keep a very complex and expensive equipment.

On the other hand, Google goes the other way – we first try to create a «working» quantum computer and then we will begin to share its capacity with clients and community.

Now it is very hard to predict how such initiatives will affect the US government. It can work on different systems based on quantum computers, but of these projects, we know nothing, unlike our own projects, completely open to the public. We believe that open-source projects in this area will benefit society. © Photo : Rcchati from Russia created the world’s first quantum blockchain

If to speak about the encryption system, they are actively discussing this issue and trying to find a solution. The good news is that today there are protocols that are secure against hacking with a quantum computers on the level of mathematics, and programmers actively develop and adapt them for practical use.

The problem is that formal verification of all these algorithms require a large amount of time and no one will be able to implement. On the other hand, we still have a few years before becoming the first full-scale quantum machine, and this time is enough to check the classical algorithms are able to withstand them.

In any case, I think, to create such an algorithm is much easier than to create a «working» quantum computer.

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