Humanity, like 60 years ago, is again on the verge of a grandiose breakthrough in the sphere computing technology... Very soon to replace today's computing machines will come quantum computers.
What progress has reached
Back in 1965, Gordon Moore said that in a year the number of transistors that fit in a silicon microchip doubles. This pace of progress recent times slowed down, and doubling occurs less frequently - once every two years. Even at this rate, in the near future, transistors will reach the size of an atom. Further - the line, which is impossible to cross. From the point of view of the physical structure of the transistor, it can in no way be less than atomic values. Increasing the size of the chip does not solve the problem. The work of transistors is associated with the release of thermal energy, and processors need a high-quality cooling system. The multi-core architecture also does not address the issue of further growth. Reaching a peak in technology development modern processors will happen soon.
Developers came to understand this problem at a time when personal computers were just beginning to appear among users. In 1980, one of the founders of quantum informatics, Soviet professor Yuri Manin, formulated the idea of \u200b\u200bquantum computing. A year later, Richard Feyman proposed the first model of a computer with a quantum processor. Theoretical basis of what quantum computers should look like was formulated by Paul Benioff.
How a quantum computer works
To understand how a new processor works, you need to have at least a superficial knowledge of the principles of quantum mechanics. It makes no sense to present mathematical layouts and formulas here. For the layman, it is enough to become familiar with three distinctive features of quantum mechanics:
- The state or position of a particle is determined only with any 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 the superposition. It is characteristic that the knowledge obtained by the measurement about the state of the particle differs from the real 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 it is open. Closed and open at the same time.
This is the striking difference in computation. An ordinary processor operates in its actions with a binary code. Computer bits can be in only one state - have a logical value of 0 or 1. Quantum computers operate with qubits, which can have a logical value of 0, 1, 0 and 1 at once. For solving certain problems, they will have a multimillion-dollar advantage over traditional computers. Today there are already dozens of descriptions of work algorithms. Programmers create a special program code, which will be able to work on new principles of computing.
Where the new computer will be applied
A new approach to the computation 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 statesmen, had great skepticism about their use in the national economy. There are people today who are full of doubts about the importance of computers of a fundamentally new generation. Very long time technical journals refused to publish articles on quantum computing, considering it a common fraudulent ploy to fool investors.
The new way of computing will create the preconditions for scientific grandiose discoveries in all industries. Medicine will solve many problematic issues, which have accumulated in recent years quite a lot. It will be possible to diagnose 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. Flying to other planets will become as mundane as daily trips around the city. The potential that lies in quantum computing will certainly transform our planet beyond recognition.
Another distinguishing feature that quantum computers have is the ability of quantum computation to quickly pick the right code or cipher. A conventional computer performs a mathematical optimization solution sequentially, iterating over one option after another. A quantum competitor works with the entire data set at once, instantly choosing the most suitable options for an unprecedented a short time... Banking transactions will be decrypted in the blink of an eye, which is not available to modern computers.
However, the banking sector may not worry - its secret will be saved by a quantum encryption method with a measurement paradox. When you try to break the code, the transmitted signal will be distorted. The information received will not make any sense. The secret services, for which spying is common, are interested in the possibilities of quantum computing.
Construction difficulties
The difficulty lies in creating conditions under which a quantum bit can be in a state of superposition for an infinitely long time.
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 the logic machine:
- temperature 0.02 degrees Kelvin (-269.98 Celsius);
- a system of protection against magnetic and electrical radiation (reduces the impact of these factors by 50 thousand times);
- heat dissipation and vibration damping system;
- rarefaction of air below atmospheric pressure by 100 billion times.
A slight deviation in the environment causes the qubits to instantly lose their superposition state, causing them to malfunction.
Ahead of the whole planet
All of the above could be attributed to the creativity of the inflamed mind of the writer of science fiction stories, if google Together with NASA, it did not purchase a D-Wave quantum computer with a processor containing 512 qubits from a Canadian research corporation last year.
With its help the market leader computer technology will resolve issues machine learning in sorting and analyzing large amounts of data.
Snowden, who left the US, also made an important revelatory 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 surpass the first commercial prototype at least 300 thousand times in speed and computational volume. The quantum computer, the photo of which is located below, is the world's first commercial option in principle new technology calculations.
To engage in scientific development he was prompted by his acquaintance at the university with the works of Colin Williams on quantum computing. It must be said that Williams is now a business project manager at Rose Corporation.
Breakthrough or scientific deception
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 her research, Rose sought to create a processor with a minimum number of 1,000 qubits. And he definitely had to have a commercial option - to sell and make money.
Many, knowing Rose's obsession and commercial acumen, try to accuse him of forgery. Allegedly, the most ordinary processor is issued as a quantum one. This is also facilitated by the fact that the new technique exhibits phenomenal speed when performing certain types of calculations. Otherwise it behaves like a completely ordinary computer, only very expensive.
When will they appear
It won't be long to wait. The research group, organized by the joint purchasers of the prototype, will soon give a report on the results of research on D-Wave.
Perhaps the time is coming soon in which quantum computers will turn our understanding of the world around us. And all of humanity at this moment will come out on more high level its evolution.
Last week news broke that Google has made a breakthrough in quantum computer development -
the company understood how such a computer would cope
with their own mistakes. Quantum computers have been talked about for several years: it, for example, on the cover of Time magazine. If such computers appear, it will be a breakthrough akin to the appearance of classical computers - if not more serious. Look At Me explains what quantum computers are good at and what exactly Google did.
What is a quantum computer?
A quantum computer is a mechanism at the intersection of computer science and quantum physics, the most difficult branch of theoretical physics. Richard Feynman, one of the greatest physicists of the 20th century, once said: "If you think you understand quantum physics, then you do not understand it." Therefore, keep in mind that the explanations that follow are incredibly simplistic. It takes people many years to understand quantum physics.
Quantum physics deals with elementary particles smaller than an atom. The way these particles are arranged and how they behave is contrary to many of our ideas about the universe. A quantum particle can be in several places at the same time - and in several states at the same time. Imagine that you toss a coin: while it is in the air, you cannot tell whether it will come up heads or tails; this coin is like heads and tails at the same time. This is how quantum particles behave. This is called the principle of superposition.
A quantum computer is still a hypothetical device that will use the principle of superposition (and other quantum properties)
for computing. An ordinary computer works with transistors,
which perceive any information as zeros and ones. Binary code can describe the whole world - and solve any problems within it. The quantum analogue of the classical bit is called the cubit (qubit, qu - from the word quantum, quantum)... Using the principle of superposition, the cubit can be simultaneously located
in state 0 and 1 - and this will not only significantly increase the power compared to traditional computers, but also allow you to solve unexpected problems,
which ordinary computers are not capable of.
The superposition principle is the only one
what will quantum computers be based on?
No. Due to the fact that quantum computers exist only in theory, scientists so far only speculate how exactly they will work. For example, it is believed that quantum computers will also employ quantum entanglement.
This is a phenomenon that Albert Einstein called "creepy" ( he was generally against quantum theory, because it does not fit with his theory of relativity)... The meaning of the phenomenon is that two particles in the Universe can be interconnected, and vice versa: say, if helicity
(there is such a characteristic of the state of elementary particles, we will not go into details) of the first particle is positive, then the helicity of the second will always be negative, and vice versa. This phenomenon is called "creepy" for two reasons. First, this connection works instantly, faster than the speed of light. Second, entangled particles can be located at any distance from each other.
from a friend: for example, at different ends of the Milky Way.
How can a quantum computer be used?
Scientists are looking for applications for quantum computers and at the same time figuring out how to build them. The main thing is that a quantum computer will be able to optimize information very quickly and generally work with big data that we accumulate, but do not yet understand how to use it.
Let's imagine this option (greatly simplified, of course): You are about to shoot a bow at a target and you need to calculate how high to aim to hit. Let's say you need to calculate the height from 0 to 100 cm. A conventional computer will calculate each trajectory in turn: first 0 cm, then 1 cm, then 2 cm, and so on. A quantum computer will calculate all the options at the same time - and instantly give out the one that will allow you to hit exactly the target. Many processes can be optimized this way:
from medicine (say, diagnose cancer earlier) before aviation (for example, do more complex autopilots).
There is also a version that such a computer will be able to solve problems for which regular computer simply not capable - or which would take him thousands of years of computation. A quantum computer will be able to work with the most complex simulations: for example, calculate whether there are intelligent beings in the Universe other than humans. It is possible that the creation of quantum computers will lead
to the emergence of artificial intelligence. Imagine what the advent of conventional computers has done to our world - quantum computers can be about the same breakthrough.
Who is developing quantum computers?
Everything. Governments, military, technology companies. Almost anyone will benefit from creating a quantum computer. For example, among the documents released by Edward Snowden, there was information that the NSA has a project "Deployment in complex goals", which includes the creation of a quantum computer to encrypt information. Microsoft is seriously engaged in quantum computers - the first research in this area, they began in 2007. IBM is in development and announced a few years ago that it had created a three-cubit chip. Finally, Google and NASA collaborate
with D-Wave, which claims to be releasing
"The first commercial quantum processor" (or rather, the second, now their model is called D-Wave Two)but it doesn't work like quantum yet -
we recall that they do not exist.
How close are we to creating
quantum computer?
Nobody can say for sure. Technology Breakthrough News (as a recent Google news) appear constantly, but we can be as very distant
from a full-fledged quantum computer, and very close to it. Let's say there are studies that suggest that it is enough to create a computer for everything
with several hundred cubits to make it work like a full-fledged quantum computer. D-Wave claims to have built an 84 kubit processor -
but critics who have analyzed their processor claim that it works,
like a classical computer, not like a quantum one. Google collaborating
with D-Wave, they believe that their processor is just in the very early stages of development and will eventually work like a quantum one. Anyway, now
quantum computers have one major problem - bugs. Any computers make mistakes, but classical computers can easily cope with them - while quantum computers do not yet. Once the researchers figure out the errors, there will be only a few years before the advent of the quantum computer.
Making it difficult to fix errors
in quantum computers?
Simplified, errors in quantum computers can be divided into two levels. The first is the mistakes that any computers make, including classic ones. An error may appear in the computer memory when 0 involuntarily changes to 1 due to external noise - for example, cosmic rays or radiation. These errors are easy to solve, all data is checked for such changes. And this problem in quantum computers was just recently dealt with at Google: they stabilized a chain of nine cubits
and saved her from mistakes. There is, however, one caveat to this breakthrough: Google has dealt with classic errors in classical computing. There is a second level of error in quantum computers, and it is much more difficult to understand and explain.
Cubits are extremely unstable, they are subject to quantum decoherence - this is a breakdown of communication within a quantum system under the influence of the environment. A quantum processor must be isolated as much as possible from environmental influences (although decoherence sometimes occurs as a result of internal processes)to keep errors to a minimum. At the same time, quantum errors cannot be completely eliminated, but if they are made rare enough, a quantum computer can work. At the same time, some researchers believe that 99% of the power of such a computer will just be directed
to eliminate errors, but the remaining 1% is enough to solve any problems.
According to physicist Scott Aaronson, Google's achievement can be considered the third
half of the seven steps required to create a quantum computer — in other words, we are halfway there.
You are all accustomed to our computers: in the morning we read 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 principle of operation of such transistors is quite simple - depending on the supplied voltage, we get another voltage at the output, which is interpreted as either logical 0 or logical 1. In order to carry out division operations, there is a bit shift - if we have, for example, there was a number 1101, then after shifting 1 bit to the left, it will be 01101, and if now 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 waste 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 devicewhich uses phenomenaquantum superposition andquantum entanglement for data transmission and processing.
It clearly did not become clearer. Quantum superposition tells us that the system with some degree of probability exists in all states possible for it (in this case, the sum of all probabilities, of course, is equal to 100% or 1). Let's take an example. Information in quantum computers is stored in qubits - if 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 it give us? Yes all! For example, we have a 4-character numeric password. How will a regular processor hack it? Simple search from 0000 to 9999.9999 in binary system has the form 10011100001111, that is, we need 14 bits to write it. 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 the problems that even supercomputers now consider for days will be solved instantly on quantum systems: is it necessary to find a substance with certain properties? No problem, make a system with the same number of qubits as you have requirements for the substance - and the answer will already be in your pocket. AI needs to be created ( artificial Intelligence? It couldn't be easier: while an ordinary PC is going through all the combinations, the 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 an ordinary PC, everything is simple - we can take and read it by directly connecting to the processor: logical 0 and 1 there are definitely interpreted 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. This is where quantum entanglement comes in. Its essence lies in the fact that you can get a pair of particles that are connected with each other (in scientific terms - if, for example, the projection of the spin of one entangled particle is negative, then the other will necessarily be positive). How does it look on your fingers? Let's say we have two boxes in which there is a piece of paper. We carry boxes to any distance, open one of them and see that the piece of paper in it is in a horizontal strip. This automatically means that the other piece of paper will be in a vertical strip. But the problem is that as soon as we know the state of one piece of paper (or particle), the quantum system collapses - the uncertainty disappears, the qubits turn into ordinary bits.
Therefore, calculations on quantum computers are essentially one-off: we create a system that consists of entangled particles (we know where their second "halves" are). We carry out calculations, and after that we “open the box with a piece of paper” - we find out the state of entangled particles, and hence the state of particles in a quantum computer, and hence the result of the calculations. So, for new calculations, you need to create qubits again - you just won't be able to "close the box with the piece of paper" - 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 trying 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 unbreakable - why don't we use them? The problem is trivial - the impossibility of realizing a quantum system in ordinary home conditions. In order for a qubit to exist in a superposition state for an infinitely long time, extremely specific conditions are needed: this is a complete vacuum (the absence of other particles), a temperature as close as possible to zero in Kelvin (for superconductivity), and a complete absence electromagnetic radiation (for no 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 state of superposition will disappear, and the calculation results will be incorrect. The second problem is to make the qubits interact with each other - when they interact, their lifetimes are drastically reduced. As a result, the maximum for a given day is quantum computers with a couple of dozen 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: 
Still, such devices are significantly (thousands of times) more powerful than conventional PCs, which can be considered a breakthrough. However, they will not replace user devices soon enough - for a start, we need to either learn how to create conditions for such devices to work at home, or, on the contrary, to "make" such devices work in our usual conditions. Steps in the second direction have already been taken - in 2013, the first two-qubit quantum computer based on doped diamonds was created, operating at room temperature. However, alas, this is just a prototype, and 2 qubits is not enough for calculations. So the wait for quantum PCs is still very, very long.
Humanity, just like 60 years ago, is again on the verge of a major breakthrough in the field of computing technology. Very soon, quantum computers will replace today's computing machines.
What progress has reached
Back in 1965, Gordon Moore said that in a year the number of transistors that fit in a silicon microchip doubles. This rate of progress has slowed down recently, and doubling occurs less frequently - once every two years. Even at this rate, in the near future, transistors will reach the size of an atom. Further - the line, which is impossible to cross. From the point of view of the physical structure of the transistor, it can in no way be less than atomic values. Increasing the size of the chip does not solve the problem. The work of transistors is associated with the release of thermal energy, and processors need a high-quality cooling system. The multi-core architecture also does not address the issue of further growth. The peak in the development of modern processor technology is coming soon.
Developers came to understand this problem at a time when personal computers were just beginning to appear. In 1980, one of the founders of quantum informatics, Soviet professor Yuri Manin, formulated the idea of \u200b\u200bquantum computing. A year later, Richard Feyman proposed the first model of a computer with a quantum processor. The theoretical foundations of what quantum computers should look like were formulated by Paul Benioff.
How a quantum computer works
To understand how a new processor works, you need to have at least a superficial knowledge of the principles of quantum mechanics. It makes no sense to present mathematical layouts and formulas here. For the layman, it is enough to become familiar with three distinctive features of quantum mechanics:
- The state or position of a particle is determined only with any 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 the superposition. It is characteristic that the knowledge obtained by the measurement about the state of the particle differs from the real 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 it is open. Closed and open at the same time.
This is the striking difference in computation. An ordinary processor operates in its actions with a binary code. Computer bits can be in only one state - have a logical value of 0 or 1. Quantum computers operate with qubits, which can have a logical value of 0, 1, 0 and 1 at once. To solve certain problems, they will have a multimillion-dollar advantage over traditional computers. Today there are already dozens of descriptions of work algorithms. Programmers create special program code that can work on new principles of computation.
Where the new computer will be applied
A new approach to the computation 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 statesmen, had great skepticism about their use in the national economy. There are people today who are full of doubts about the importance of computers of a fundamentally new generation. For quite a long time, technical journals refused to publish articles on quantum computing, considering it a common fraudulent ploy to fool investors.
The new way of computing will create the preconditions for scientific grandiose discoveries in all industries. Medicine will solve many problematic issues, which have accumulated in recent years quite a lot. It will be possible to diagnose 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. Flying to other planets will become as mundane as daily trips around the city. The potential that lies in quantum computing will certainly transform our planet beyond recognition.
Another distinguishing feature that quantum computers have is the ability of quantum computation to quickly pick the right code or cipher. A conventional computer performs a mathematical optimization solution sequentially, iterating over one option after another. A quantum competitor works with the entire data set at once, instantly choosing the most suitable options in an unprecedentedly short time. Banking transactions will be decrypted in the blink of an eye, which is not available to modern computers.
However, the banking sector may not worry - its secret will be saved by a quantum encryption method with a measurement paradox. When you try to break the code, the transmitted signal will be distorted. The information received will not make any sense. The secret services, for which spying is common, are interested in the possibilities of quantum computing.
Construction difficulties
The difficulty lies in creating conditions under which a quantum bit can be in a state of superposition for an infinitely long time.
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 the logic machine:
- temperature 0.02 degrees Kelvin (-269.98 Celsius);
- a system of protection against magnetic and electrical radiation (reduces the impact of these factors by 50 thousand times);
- heat dissipation and vibration damping system;
- rarefaction of air below atmospheric pressure by 100 billion times.
A slight deviation in the environment causes the qubits to instantly lose their superposition state, causing them to malfunction.
Ahead of the whole planet
All of the above could be attributed to the creativity of the inflamed mind of the writer of science fiction stories, if Google, together with NASA, had not acquired a D-Wave quantum computer from a Canadian research corporation last year, with a processor containing 512 qubits.
With its help, the leader in the computer technology market will solve the problems of machine learning in sorting and analyzing large amounts of data.
Snowden, who left the US, also made an important revelatory 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 surpass the first commercial prototype at least 300 thousand times in speed and computational volume. The quantum computer, photo of which is located below, is the world's first commercial version of a fundamentally new computing technology.
To engage in scientific development he was prompted by his acquaintance at the university with the works of Colin Williams on quantum computing. It must be said that Williams is now a business project manager at Rose Corporation.
Breakthrough or scientific deception
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 her research, Rose sought to create a processor with a minimum number of 1,000 qubits. And he definitely had to have a commercial option - to sell and make money.
Many, knowing Rose's obsession and commercial acumen, try to accuse him of forgery. Allegedly, the most ordinary processor is issued as a quantum one. This is also facilitated by the fact that the new technique exhibits phenomenal speed when performing certain types of calculations. Otherwise it behaves like a completely ordinary computer, only very expensive.
When will they appear
It won't be long to wait. The research group, organized by the joint purchasers of the prototype, will soon give a report on the results of research on D-Wave.
Perhaps the time is coming soon in which quantum computers will turn our understanding of the world around us. And all of humanity at this moment will reach a higher level of its evolution.
In order to more or less fully reveal the essence of quantum computer technologies, let us first touch on the history of quantum theory.
It was born thanks to two scientists whose research results were awarded Nobel Prizes: the discovery of a quantum by M. Planck in 1918 and A. Einstein of a photon in 1921.
The year of the birth of the idea of \u200b\u200ba quantum computer was 1980, when Benioff was able to successfully demonstrate in practice the correctness of quantum theory.
Well, the first prototype of a quantum computer was created by Gershenfeld and Chuang in 1998 at the Massachusetts Institute of Technology (MTI). The same group of researchers created more advanced models in the next two years.
For a layman, a quantum computer is something absolutely fantastic in scale, it is calculating machine, in front of which an ordinary computer is like an account in front of a computer. And, of course, this is something very far from embodiment.
For a person who is associated with quantum computers, this is a device whose general principles of operation are more or less clear, but there are many problems that must be solved before it can be embodied in hardware, and now there are many laboratories around the world. they are trying to overcome obstacles. 
In the field of quantum technology, there have already been successes in the past and private companies, including IBM and DWays.
They regularly report on the latest achievements in this area even today. Most of the research is carried out by Japanese and American scientists. Japan in pursuit of world leadership in hardware and software spends huge amounts of money on developments in this area. According to the vice president of Hewlett-Packard, up to 70% of all studies were carried out in the land of the rising sun. Quantum computers are one of the steps of their purposeful company to seize leadership in the global market.
What explains the desire to master these technologies? Their undisputed weighty advantages over semiconductor computers!
WHAT IS IT?
A quantum computer is a computing device that works on the basis of quantum mechanics.
Today, a full-scale quantum computer is a hypothetical device that cannot be created using the available data in quantum theory.
A quantum computer does not use classical algorithms for computation, but more complex processes of a quantum nature, which are also called quantum algorithms. These algorithms use quantum mechanical effects: quantum entanglement and quantum parallelism.
To understand why a quantum computer is needed at all, it is necessary to understand the principle of its operation.
If a conventional computer works by performing sequential operations with zeros and ones, then a quantum computer uses rings of a superconducting film. The current can flow through these rings in different directions, so a chain of such rings can simultaneously implement many more operations with zeros and ones.
It is high power that is the main advantage of a quantum computer. Unfortunately, these rings are subject to even the slightest external influences, as a result of which the direction of the current may change, and the calculations turn out to be incorrect in this case.
THE DIFFERENCE OF A QUANTUM COMPUTER FROM A CONVENTIONAL
the main difference between quantum computers and ordinary computers is that data storage, processing and transmission occurs not with the help of “bits”, but “qubits” - simply speaking, “quantum bits”. Like an ordinary bit, a qubit can be in the usual states "| 0\u003e" and "| 1\u003e", and besides that, in a state of superposition A · | 0\u003e + B · | 1\u003e, where A and B are any complex numbers satisfying the condition | A | 2 + | B | 2 \u003d 1.
TYPES OF QUANTUM COMPUTERS
There are two types of quantum computers. Both are based on quantum phenomena, only of a different order.
computers based on quantization of magnetic flux based on superconductivity violations - Josephson junctions. Linear amplifiers, analog-to-digital converters, SQUIDs and correlators are already being made on the Josephson effect. element base used in the project of creating a petaflop (1015 op./s) computer. Experimentally achieved clock frequency 370 GHz, which in the future can be brought up to 700 GHz. However, the skew time of wave functions in these devices is comparable to the switching time of individual valves, and in fact, on new ones, quantum principles the already familiar element base is being implemented - triggers, registers and others logic gates.
Another type of quantum computers, also called quantum coherent computers, requires maintaining the coherence of the wave functions of the qubits used throughout the entire computation time - from start to finish (a qubit can be any quantum mechanical system with two allocated energy levels). As a result, for some tasks, the computational power of coherent quantum computers is proportional to 2N, where N is the number of qubits in the computer. It is the latter type of device that is meant when we talk about quantum computers.
QUANTUM COMPUTERS NOW
But small quantum computers are being built today. The D-Wave Systems company is especially active in this direction, which back in 2007 created a quantum computer of 16 qubits. This computer successfully coped with the task of seating guests at the table, based on the fact that some of them disliked each other. Now D-Wave Systems continues to develop quantum computers.
A group of physicists from Japan, China and the United States for the first time managed to build in practice a quantum computer based on the von Neumann architecture - that is, with the physical separation of a quantum processor and quantum memory. IN this moment For the practical implementation of quantum computers (computers based on the unusual properties of objects of quantum mechanics), physicists use all sorts of exotic objects and phenomena - ions trapped in an optical trap, nuclear magnetic resonance. For the new work, scientists relied on miniature superconducting circuits - the ability to implement a quantum computer using such circuits was described in Nature in 2008.
The computer assembled by the scientists consisted of quantum memory, the role of which was played by two microwave resonators, a processor of two qubits connected by a bus (the resonator also played its role, and the qubits were superconducting circuits), and devices for data erasure. Using this computer, scientists have implemented two main algorithms - the so-called quantum Fourier transform, and conjunction using quantum Toffoli logic gates:
The first algorithm is a quantum analogue of the discrete Fourier transform. Its distinctive feature is a much smaller (of the order of n2) number of functional elements in the implementation of the algorithm in comparison with the analogue (of the order of n 2n). Discrete Fourier transforms are used in a wide variety of areas of human activity - from the study of partial differential equations to data compression.
In turn, Toffoli's quantum logic gates are basic elements, from which, with some additional requirements, you can get any Boolean function (program). Distinctive feature These elements are reversible, which, from the point of view of physics, among other things, minimizes the heat release of the device.
According to scientists, the system they created has one remarkable advantage - it is easily scalable. Thus, it can serve as a kind of building block for future computers. According to the researchers, the new results clearly demonstrate the promise of the new technology.
