How quantum computers will change the world. Just about the complex: what is a quantum computer and why is it needed?

You are all accustomed to our computers: in the morning we read the news from a smartphone, in the afternoon we work with a laptop, and in the evening we watch movies on a tablet. All these devices have one thing in common - a silicon processor consisting of billions of transistors. The operating principle of such transistors is quite simple - depending on the supplied voltage, we get a different voltage at the output, which is interpreted either as logical 0 or logical 1. In order to carry out division operations, there is a bit shift - if we, for example, was the number 1101, then after shifting it by 1 bit to the left it will be 01101, and if now we shift it by 1 bit to the right it will be 01110. And the main problem lies in the fact that for the same division several dozen such operations may be needed. Yes, given the fact that there are billions of transistors, such an operation takes nanoseconds, but if there are many operations, we lose time on these calculations.

How quantum computers work

A quantum computer offers a completely different way of computing. Let's start with the definition:

Quantum computer -computing device, which uses phenomenaquantum superpositionAndquantum entanglementfor data transmission and processing.

It clearly hasn't become any clearer. Quantum superposition tells us that a system, with some degree of probability, exists in all states possible for it (the sum of all probabilities, of course, is equal to 100% or 1). Let's look at this with an example. Information in quantum computers is stored in qubits - while ordinary bits can have a state of 0 or 1, then a qubit can have a state of 0, 1, and 0 and 1 at the same time. Therefore, if we have 3 qubits, for example 110, then this expression in bits is equivalent to 000, 001, 010, 011, 100, 101, 110, 111.

What does this give us? That's it! For example, we have a 4-character digital password. How will it be hacked? regular processor? Simply search from 0000 to 9999. 9999 in binary system has the form 10011100001111, that is, to write it we need 14 bits. Therefore, if we have a quantum PC with 14 qubits, we already know the password: after all, one of the possible states of such a system is the password! As a result, all problems that even supercomputers now take days to calculate will be solved instantly using quantum systems: do you need to find a substance with certain properties? No problem, make a system with the same number of qubits as your requirements for matter - and the answer will already be in your pocket. Do you need to create AI (artificial intelligence? It couldn’t be simpler: while a regular PC will try all the combinations, a quantum computer will work with lightning speed, choosing the best answer.

It would seem that everything is great, but there is one important problem - how do we find out the result of the calculations? With a regular PC, everything is simple - we can take it and read it by directly connecting to the processor: logical 0 and 1 are definitely interpreted there as the absence and presence of charge. But this will not work with qubits - after all, at every moment of time it is in an arbitrary state. And this is where quantum entanglement comes to our aid. Its essence lies in the fact that you can get a pair of particles that are connected to each other (in scientific terms - if, for example, the spin projection of one entangled particle is negative, then the other will definitely be positive). What does it look like on your fingers? Let's say we have two boxes each containing a piece of paper. We carry boxes to any distance, open one of them and see that the piece of paper in it is horizontally striped. This automatically means that the other piece of paper will have vertical stripes. But the problem is that as soon as we know the state of one piece of paper (or particle), the quantum system collapses - uncertainty disappears, qubits turn into ordinary bits.

Therefore, calculations on quantum computers are essentially one-time: we create a system that consists of entangled particles (we know where their other “halves” are located). We carry out calculations, and after that we “open the box with the piece of paper” - we find out the state of the entangled particles, and therefore the state of the particles in the quantum computer, and therefore the result of the calculations. So for new calculations, you need to create qubits again - simply “closing the box with the piece of paper” will not work - after all, we already know what is drawn on the piece of paper.

The question arises - since a quantum computer can instantly guess any passwords - how to protect information? Will privacy disappear with the advent of such devices? Of course not. The so-called quantum encryption comes to the rescue: it is based on the fact that when you try to “read” a quantum state, it is destroyed, which makes any hacking impossible.

Home quantum computer

Well last question- since quantum computers are so cool, powerful and unhackable - why don’t we use them? The problem is trivial - the impossibility of implementing a quantum system in ordinary home conditions. In order for a qubit to exist in a state of superposition indefinitely, extremely specific conditions are needed: complete vacuum (absence of other particles), a temperature as close as possible to zero Kelvin (for superconductivity), and the complete absence of electromagnetic radiation(for absence of influence on the quantum system). Agree, it is difficult to create such conditions at home, to put it mildly, but the slightest deviation will lead to the fact that the superposition state will disappear and the calculation results will be incorrect. The second problem is getting the qubits to interact with each other - when interacting, their lifetime is catastrophically reduced. As a result, the maximum for this day is quantum computers with a couple of tens of qubits.

However, there are quantum computers from D-Wave that have 1000 qubits, but, generally speaking, they are not real quantum computers, because they do not use the principles of quantum entanglement, so they cannot work according to classical quantum algorithms:

But still, such devices turn out to be significantly (thousands of times) more powerful than conventional PCs, which can be considered a breakthrough. However, they will not replace user devices any time soon - first we need to either learn to create conditions for the operation of such devices at home, or, on the contrary, “make” such devices work in the conditions we are familiar with. Steps in the second direction have already been taken - in 2013, the first two-qubit quantum computer was created on impurity diamond, operating at room temperature. However, alas, this is just a prototype, and 2 qubits are not enough for calculations. So the wait for quantum PCs is still very, very long.

In recent decades, computers have developed very quickly. In fact, within the memory of one generation, they have gone from bulky lamp-based ones that occupy huge rooms to miniature tablets. Memory and speed increased rapidly. But the moment came when tasks appeared that were beyond the control of even super-powerful modern computers.

What is a quantum computer?

The emergence of new tasks beyond the capabilities of conventional computers forced us to look for new opportunities. And, as an alternative to conventional computers, quantum computers appeared. A quantum computer is a computing technology based on elements of quantum mechanics. The basic principles of quantum mechanics were formulated at the beginning of the last century. Its appearance made it possible to solve many problems in physics that could not find solutions in classical physics.

Although quantum theory is already in its second century, it still remains understandable only to a narrow circle of specialists. But there are also real results of quantum mechanics, to which we are already accustomed - laser technology, tomography. And at the end of the last century, the theory of quantum computing was developed by the Soviet physicist Yu. Manin. Five years later, David Deutsch unveiled the idea of a quantum machine.

Does a quantum computer exist?

But the implementation of ideas turned out to be not so simple. From time to time, reports appear that another quantum computer has been created. On the development of such computer technology There are giants in the field of information technology:

D-Wave is a company from Canada that was the first to produce operational quantum computers. Nevertheless, there is debate among experts about how quantum these computers really are and what advantages they provide.
IBM created a quantum computer, and opened access to it for Internet users to experiment with quantum algorithms. By 2025, the company plans to create a model capable of solving practical problems.
Google has announced the release this year of a computer capable of proving the superiority of quantum over conventional computers.
In May 2017, Chinese scientists in Shanghai announced that they had created the most powerful quantum computer in the world, exceeding analogues in signal processing frequency by 24 times.
In July 2017, at the Moscow Conference on Quantum Technologies, it was announced that a 51-qubit quantum computer had been created.

How does a quantum computer differ from a conventional one?

The fundamental difference between a quantum computer is its approach to the calculation process.

In a conventional processor, all calculations are based on bits that have two states, 1 or 0. That is, all work comes down to analyzing a huge amount of data to determine whether it meets the specified conditions. A quantum computer is based on qubits (quantum bits). Their feature is the ability to be in the state 1, 0, and also 1 and 0 at the same time.
The capabilities of a quantum computer increase significantly, since there is no need to search for the desired answer among many. In this case, the answer is selected from already available options with a certain probability of matching.

What is a quantum computer used for?

The principle of a quantum computer, built on choosing a solution with a sufficient degree of probability and the ability to find such a solution many times faster than modern computers, determines the purposes of its use. First of all, the emergence of this type of computing technology worries cryptographers. This is due to the quantum computer's ability to easily calculate passwords. Thus, the most powerful quantum computer created by Russian-American scientists is capable of obtaining the keys to existing systems encryption.

There are more useful ones applied problems for quantum computers, they are related to the behavior of elementary particles, genetics, healthcare, financial markets, protecting networks from viruses, artificial intelligence and many others that ordinary computers cannot yet solve.

How does a quantum computer work?

The design of a quantum computer is based on the use of qubits. The following are currently used as physical executions of qubits:

rings made of superconductors with jumpers, with multidirectional current;
individual atoms exposed to laser beams;
ions;
photons;
Options for using semiconductor nanocrystals are being developed.

Quantum computer - operating principle

If there is certainty in how a classical computer works, then the question of how a quantum computer works is not easy to answer. The description of the operation of a quantum computer is based on two phrases that are obscure to most:

superposition principle– we are talking about qubits that can be simultaneously in positions 1 and 0. This allows you to carry out several calculations simultaneously, rather than sort through options, which gives big win in time;
quantum entanglement- a phenomenon noted by A. Einstein, which consists in the interrelation of two particles. Speaking in simple words, if one of the particles has positive helicity, then the second instantly takes on a positive one. This relationship occurs regardless of distance.

Who invented the quantum computer?

The basis of quantum mechanics was outlined at the very beginning of the last century as a hypothesis. Its development is associated with such brilliant physicists as Max Planck, A. Einstein, Paul Dirac. In 1980, Yu. Antonov proposed the idea of the possibility of quantum computing. A year later, Richard Feineman theoretically modeled the first quantum computer.

Now the creation of quantum computers is in the development stage and it is even difficult to imagine what a quantum computer is capable of. But it is absolutely clear that mastering this direction will bring people many new discoveries in all areas of science, will allow them to look into the micro and macro world, and learn more about the nature of the mind and genetics.

According to experts, very soon, in 10 years, microcircuits in computers will reach atomic measurements. It seems logical that the era of quantum computers is coming, with the help of which speed computing systems may increase by several orders of magnitude.

The idea of quantum computers is relatively new: in 1981, Paul Benioff first theoretically described the principles of operation of a quantum Turing machine.

In the 1930s, Alan Turing first described a theoretical device that was endless tape divided into small cells. Each cell can contain the character 1 or 0, or remains empty.

The control device moves along the tape, reading characters and writing new ones. From a set of such symbols a program is compiled that the machine must execute.

In the quantum Turing machine proposed by Benioff, the operating principles remain the same, with the difference that both the tape and the control device are in a quantum state.

This means that the symbols on the tape can be not only 0 and 1, but also superpositions of both numbers, i.e. 0 and 1 at the same time. Thus, if a classical Turing machine is capable of performing only one calculation at a time, then a quantum one performs several calculations in parallel.

Today's computers work on the same principle as normal Turing machines - with bits that are in one of two states: 0 or 1. Quantum computers have no such restrictions: the information in them is encrypted in quantum bits (qubits), which can contain superposition of both states.

Working on part of the D-Wave quantum computer

©D-Wave Systems

Physical systems that implement qubits can be atoms, ions, photons or electrons that have two quantum states. In fact, if you make elementary particles information carriers, you can use them to build computer memory and new generation processors.

Thanks to the superposition of qubits, quantum computers are initially designed to perform parallel computing. This parallelism, according to physicist David Deutsch, allows quantum computers to perform millions of calculations simultaneously, while modern processors work with only one.

A 30-qubit quantum computer will be equal in power to a supercomputer operating at 10 teraflops (trillion operations per second). Power of modern desktop computers measured in just gigaflops (billion operations per second).

Another important quantum mechanical phenomenon that may be involved in quantum computers is called "entanglement." The main problem with reading information from quantum particles is that during the measurement process they can change their state in a completely unpredictable way.

In fact, if we read information from a qubit in a superposition state, we will only get 0 or 1, but never both numbers at the same time. This means that instead of a quantum one, we will be dealing with a normal classical computer.

To solve this problem, scientists must use measurements that do not destroy the quantum system. Quantum entanglement provides a potential solution.

IN quantum physics, if you apply an external force to two atoms, they can be “entangled” together in such a way that one of the atoms will have the properties of the other. This, in turn, will lead to the fact that, for example, when measuring the spin of one atom, its “entangled” twin will immediately take the opposite spin.

This property of quantum particles allows physicists to know the value of a qubit without measuring it directly.

One day, quantum computers could replace silicon chips, just as transistors replaced vacuum tubes. However modern technologies do not yet allow the construction of full-fledged quantum computers.

Assembly of the D-Wave Two quantum computer processor

©D-Wave Systems

However, every year, researchers announce new advances in quantum technology, and hope continues to grow that quantum computers will one day be able to surpass conventional ones.

1998

Researchers from the Massachusetts Institute of Technology have succeeded for the first time in distributing one qubit between three nuclear spins in each molecule of liquid alanine or trichloroethylene molecule. This distribution made it possible to use “entanglement” for non-destructive analysis of quantum information.

2000

In March, scientists at Los Alamos National Laboratory announced the creation of a 7-qubit quantum computer in a single drop of liquid.

2001

Demonstration of the calculation of the Shor algorithm by specialists from IBM and Stanford University on a 7-qubit quantum computer.

2005

The Institute of Quantum Optics and Quantum Information at the University of Innsbruck was the first to create a qubit (a combination of 8 qubits) using ion traps.

2007

Canadian company D-Wave has demonstrated the first 16-qubit quantum computer capable of solving a range of problems and puzzles, such as Sudoku.

Since 2011, D-Wave has offered for $11 million the D-Wave One quantum computer with a 128-qubit chipset that performs only one task - discrete optimization.

Humanity, like 60 years ago, is again on the verge of a grandiose breakthrough in the field of computing technologies. Very soon to replace today's computers Quantum computers will come.

How far has the progress come?

Back in 1965, Gordon Moore said that in a year the number of transistors that fit on a silicon microchip doubles. This pace of progress lately has slowed down, and doubling occurs less frequently - once every two years. Even this pace will allow transistors to reach the size of an atom in the near future. Next is a line that cannot be crossed. From the point of view of the physical structure of the transistor, it cannot in any way be smaller than atomic quantities. Increasing the chip size does not solve the problem. The operation of transistors is associated with the release of thermal energy, and processors need a high-quality cooling system. Multi-core architecture also does not solve the issue of further growth. Reaching the peak in technology development modern processors will happen soon.
Developers came to understand this problem at a time when users were just beginning to have personal computers. In 1980, one of the founders of quantum information science, Soviet professor Yuri Manin, formulated the idea of quantum computing. A year later, Richard Feyman proposed the first model of a computer with a quantum processor. Theoretical foundations Paul Benioff formulated what quantum computers should look like.

How a quantum computer works

To understand how it works new processor, you must have at least a superficial knowledge of the principles of quantum mechanics. There is no point in giving mathematical layouts and formulas here. It is enough for the average person to become familiar with the three distinctive features of quantum mechanics:

The state or position of a particle is determined only with some degree of probability.
If a particle can have several states, then it is in all possible states at once. This is the principle of superposition.
The process of measuring the state of a particle leads to the disappearance of superposition. It is characteristic that the knowledge about the state of the particle obtained by the measurement differs from the actual state of the particle before the measurements.

From the point of view of common sense - complete nonsense. In our ordinary world, these principles can be represented as follows: the door to the room is closed, and at the same time open. Closed and open at the same time.

This is the striking difference between calculations. A conventional processor operates in its actions binary code. Computer bits can only be in one state - have boolean value 0 or 1. Quantum computers operate with qubits, which can have the logical value 0, 1, 0 and 1 at once. For solving certain problems, they will have a multimillion-dollar advantage over traditional computing machines. Today there are already dozens of descriptions of work algorithms. Programmers create a special program code, which can work according to new principles of calculations.

Where will the new computer be used?

A new approach to the computing process allows you to work with huge amounts of data and perform instant computational operations. With the advent of the first computers, some people, including government officials, had great skepticism regarding their use in the national economy. There are still people today who are full of doubts about the importance of computers of a fundamentally new generation. Very for a long time Tech journals refused to publish articles on quantum computing, considering the field a mere scam to fool investors.

A new method of computing will create the preconditions for grandiose scientific discoveries in all industries. Medicine will solve many problematic issues, of which quite a lot have accumulated recently. will become possible diagnostics cancer at an earlier stage of the disease than now. The chemical industry will be able to synthesize products with unique properties.

A breakthrough in astronautics will not be long in coming. Flights to other planets will become as commonplace as daily trips around the city. The potential inherent in quantum computing will certainly transform our planet beyond recognition.

Other distinctive feature that quantum computers have is the ability of quantum computing to quickly find required code or cipher. An ordinary computer performs a mathematical optimization solution sequentially, trying one option after another. The quantum competitor works with the entire array of data at once, choosing the most suitable options for unprecedented short time. Bank transactions will be decrypted in the blink of an eye, which is inaccessible to modern computers.

However, the banking sector need not worry - its secret will be saved by the quantum encryption method with a measurement paradox. When you try to open the code, the transmitted signal will be distorted. The information received will not make any sense. Secret services, for whom espionage is a common practice, are interested in the possibilities of quantum computing.

Design difficulties

The difficulty lies in creating conditions under which a quantum bit can remain in a state of superposition indefinitely.

Each qubit is a microprocessor that operates on the principles of superconductivity and the laws of quantum mechanics.

A number of unique environmental conditions are created around the microscopic elements of a logic machine:

temperature 0.02 degrees Kelvin (-269.98 Celsius);
protection system against magnetic and electrical radiation (reduces the impact of these factors by 50 thousand times);
heat removal and vibration damping system;
air rarefaction is 100 billion times lower than atmospheric pressure.

A slight deviation in the environment causes the qubits to instantly lose their superposition state, resulting in malfunction.

Ahead of the rest of the planet

All of the above could be attributed to the creativity of the fevered mind of a writer of science fiction stories, if Google company Together with NASA, it did not purchase the D-Wave quantum computer last year from the Canadian research corporation, the processor of which contains 512 qubits.

With its help, the market leader computer technology will solve machine learning issues in sorting and analyzing large data sets.

Snowden, who left the United States, also made an important revealing statement - the NSA also plans to develop its own quantum computer.

2014 - the beginning of the era of D-Wave systems

Successful Canadian athlete Geordie Rose, after a deal with Google and NASA, began building a 1000-qubit processor. The future model will exceed the first commercial prototype by at least 300 thousand times in speed and volume of calculations. The quantum computer, the photo of which is located below, is the world's first commercial version of the fundamental new technology calculations.

He was prompted to engage in scientific development by his acquaintance at the university with the works of Colin Williams on quantum computing. It must be said that Williams today works at Rose's corporation as a business project manager.

Breakthrough or scientific hoax

Rose himself does not fully know what quantum computers are. In ten years, his team has gone from creating a 2-qubit processor to today's first commercial brainchild.

From the very beginning of his research, Rose sought to create a processor with a minimum number of qubits of 1 thousand. And he definitely had to have a commercial option - in order to sell and make money.

Many, knowing Rose's obsession and commercial acumen, are trying to accuse him of forgery. Allegedly, the most ordinary processor is passed off as quantum. This is also facilitated by the fact that the new technology exhibits phenomenal performance when performing certain types of calculations. Otherwise, it behaves like a completely ordinary computer, only very expensive.

When will they appear

There's not long to wait. A research group organized by the joint purchasers of the prototype will report on the results of the research on D-Wave in the near future.
Perhaps the time is coming soon in which quantum computers will revolutionize our understanding of the world around us. And all of humanity at this moment will reach more high level its evolution.

The amount of information in the world increases annually by 30%. In the last five years alone, humanity has been produced more data than in all previous history. Internet of Things systems are emerging, in which each sensor sends and receives huge amounts of data every second, and analysts predict that the number of Internet-connected things will soon exceed the number of human users. These colossal amounts of information need to be stored somewhere and processed somehow.

Now there are already supercomputers with a capacity of more than 50 petaflops (1 petaflops = 1 thousand trillion operations per second). However, sooner or later we will hit the physical limit of the possible power of processors. Of course, supercomputers will still be able to grow in size, but this is not a solution to the problem, since the size will eventually reach its limits. According to scientists, Moore's law will soon cease to apply and humanity will need new, much more powerful devices and data processing technologies. Therefore, large IT companies are already working on creating a completely new revolutionary type of computer, the power of which will be hundreds of times greater than what we have today. This is a quantum computer. Experts promise that thanks to it, it may be possible to find a cure for cancer, instantly find criminals by analyzing camera footage, and simulate DNA molecules. Now it’s even difficult to imagine what other problems he will be able to solve.

Microsoft is trying to be at the forefront of development in this area, having been studying it for twenty years, because whoever is the first to create a quantum computer will receive an undeniable competitive advantage. Moreover, the company is not only working on creating hardware, but also recently introduced a programming language that developers can use. In fact, very few people can boast that they understand the principles of operation of this revolutionary device; for most of us it is something out of science fiction. So what is he?

One of the most important parts of a computer, on which its power directly depends, is the processor, which, in turn, consists of a huge number of transistors. Transistors are the simplest parts of the system, they are somewhat similar to switches and can only be in two positions: either “on” or “off”. It is from the combinations of these provisions that the binary code, consisting of zeros and ones, on which all programming languages are based.

Accordingly, than more powerful computer, the more transistors are needed for its operation. Manufacturers are constantly reducing their sizes, trying to fit as much as possible larger number into processors. For example, in the new Xbox One X billions of them.

Now the size of one transistor is 10 millimicrons, that is, one hundred thousandth of a millimeter. But one day a physical limit will be reached, smaller than which the transistor simply cannot be made. In order to avoid a crisis in the development of IT, scientists are working on creating a computer that will work on a completely different principle - quantum. The transistors that will make up a quantum computer can be in two positions at the same time: “on” and “off” and, accordingly, can be both one and zero at once, this is called “superposition”.

If we take 4 standard transistors (bits), then they, working together, can create 16 different combinations of ones and zeros. One at a time.

If we consider 4 quantum transistors (qubits), then they can be all 16 combinations at the same time. This is a huge space and time saver!

But, of course, creating qubits is very, very difficult. Scientists have to deal with subatomic particles that obey the laws of quantum mechanics, developing a completely new approach to programming and language.

There are various types qubits Microsoft experts, for example, are working on creating topological qubits. They are incredibly fragile and easily destroyed by the slightest sound waves or thermal radiation. For stable operation they need to constantly be at a temperature of –273°C. However, they also have a number of advantages over other types: the information stored in them is practically error-free, and, accordingly, a quantum computer created on the basis of topological qubits will be an ultra-reliable system.

Quantum Microsoft computer consists of three main levels: the first level is the quantum computer itself, containing qubits and constantly located at a temperature close to absolute zero; the next level - a cryogenic computer - is also absolutely new type a computer that controls the quantum and operates at a temperature of –268°C; the last level is a computer, which a person can already work on, and controls the entire system. Such computers will be 100–300 times more powerful than the most advanced supercomputers that exist today.

Today, the world has come closer than ever to the invention of a real quantum computer: there is an understanding of the principle of its operation, prototypes. And at that moment when the power regular computers there will no longer be enough information to process all the information existing on Earth, a quantum computer will appear, which will mark a completely new era digital technologies.