The principle of operation and the scope of a quantum computer

Computer computing helps us to do what we don’t want or can’t do mainly because of complexity, because of the likelihood of involuntary errors, and because of time. For example, raising a number to the 128th degree in the mind.

The purpose and use of a quantum computer.

What is a quantum computer?

The most powerful quantum computer (QC) is - or, rather, would be - a completely different mechanism, different from everything ever created by man. The most powerful servers today look like only a small part of what a full-fledged quantum computer can ultimately do.

In simple terms, the goal of research in the field of quantum computing is to discover the means of accelerating the execution of long-wave instructions. It would be wrong to say that CC runs programs faster than a PC or x86 server. The “program” for QC is a completely different encoding order than ever existing for a binary processor. After the birth of computers, complex physical calculations were performed, which in the 1940s helped the United States to create an atomic bomb. After the invention of the transistor, the dimensions of these systems were significantly reduced. Then came the idea of ​​parallel processors working on tasks simultaneously.

Quantum computing is just the next step. There are a lot of problems that modern computers require considerable time to solve, for example, solving a linear system of equations, optimizing parameters for support vectors, finding the shortest path through an arbitrary section or searching the unstructured list. These are pretty abstract problems now, but if you know a little about algorithms or programming, you can see how useful this can be. As an example, graphics processors (GPUs) were invented for the sole purpose of rendering triangles and then merging them into a two or three-dimensional world. And now Nvidia is a billion-dollar company. Are there any technologies of quantum computing or some of its historical derivatives, which people now find good use? In other words, what does a quantum actually do and to whom does it serve directly?

What is a quantum computer for?

Navigation. This is one of the main applications of quantum computers. The GPS system cannot work anywhere on the planet, especially under water. QC requires that atoms are supercooled and suspended in a state that makes them particularly sensitive. In an attempt to capitalize on this, competing teams of scientists are seeking to develop a kind of quantum accelerometer that can provide very accurate motion data. The most significant contributions to the development of the industry makes the French Laboratory of Photonics and Nanoscience. A vivid example of this is an attempt to create a hybrid component that combines an accelerometer with a classical one and then uses a high-pass filter to subtract classical data from quantum data. The result, if implemented, will be an extremely accurate compass that will eliminate the displacement and drift of the scale factor, usually associated with gyroscopic components.

Seismology. The same extreme sensitivity can be used to detect the presence of oil and gas deposits, as well as potential seismic activity in places where conventional sensors have not yet been used. In July 2017, QuantIC demonstrated how a quantum gravimeter detects the presence of deeply hidden objects by measuring oscillations in a gravitational field. If such a device is made not only practical, but also portable, the team believes that it can become invaluable in an early warning system for predicting seismic events and tsunamis. Pharmaceuticals. In the foreground are research in the fight against diseases such as Alzheimer's disease and multiple sclerosis; scientists use software that simulates the behavior of artificial antibodies at the molecular level.

Physics. This is actually the reason for the very existence of the concept. During his speech in 1981 at Caltech, Professor Richard Feynman, father of quantum electrodynamics (QED), suggested that the only way to build a successful simulation of the physical world at the quantum level is a machine that obeys the laws of quantum physics and mechanics. It was during this speech that Professor Feynman explained, and the rest of the world realized that it would not be enough for a computer to generate a probability table and how to roll the dice. Moreover, to obtain results that the physicists themselves would not call apocryphal, would require a mechanism that behaved in the same vein as the behavior that he intended to imitate.

Machine learning. The main theory of supporters is that such systems can be adapted to “study” state patterns in huge parallel waves, and not in successive scans. Ordinary mathematics can describe a set of probable results in the form of vectors in a wild-configuration space. Decryption Here, finally, is the breakthrough that threw the first bright light on such calculations. What makes encryption codes so complex, even for modern classic computers, is that they are based on extremely large numbers of factors that require an excessive amount of time to guess by the matching method. A working QC must isolate and identify such factors in a matter of minutes, which makes the RSA coding system effectively obsolete.

Encryption. The concept, called quantum key distribution (QKD), gives a theoretical hope that the types of public and private keys that we use today to encrypt messages can be replaced by keys that are subject to entanglement effects. In theory, any third party who cracked the key and tried to read the message would immediately destroy the message for everyone. Of course, this may be enough. But the QKD theory is based on a huge assumption that has yet to be tested in the real world: that the values ​​obtained with the help of entangled qubits are themselves entangled and subject to effects wherever they go.

What is the difference between a quantum computer and an ordinary one?

A classic computer performs calculations using bits that are 0 (“off”) and 1 (“on”). It uses transistors to process information in the form of sequences of zeros and so-called computer binary languages. More transistors, more processing options - this is the main difference. QC uses the laws of quantum mechanics. Just like a classic computer that uses zeros and ones. These states can be reached in particles due to their internal angular momentum, called spin. Two states 0 and 1 can be represented in the back particles. For example, a clockwise rotation represents 1, and a counterclockwise represents 0. The advantage of using QC is that a particle can be in several states at the same time. This phenomenon is called superposition. Because of this phenomenon, QC can simultaneously reach state 0 and 1. Thus, in a classical computer, information is expressed in terms of one number 0 or 1. QC uses outputs that are described as 0 and 1 at the same time, which gives greater computational power.

How does a quantum computer

Quantum computing is computing using quantum mechanical phenomena such as superposition and entanglement. QC is a device that performs quantum computing and consists of microprocessors. Such a computer is completely different from binary digital electronic computers based on transistors and capacitors. While conventional digital computations require that the data be encoded into binary digits (bits), each of which is always in one of two specific states (0 or 1), quantum computation uses bits or qubits that can be in a superposition. The device of the quantum Turing machine is a theoretical model of such a computer and is also known as the universal QC. The area of ​​quantum computing was started by the works of Paul Benioff and Yuri Manin in 1980, Richard Feynman in 1982, and David Deutsch in 1985.

The principle of the quantum computer

Since 2018, the principle of operation of quantum computers is still in its infancy, but experiments have been conducted in which quantum computational operations were performed with a very small number of quantum bits. Both practical and theoretical research is ongoing, and many national governments and military agencies are funding research on quantum computing in additional efforts to develop quantum computers for civil, business, trade, environmental, and national security goals, such as cryptanalysis. Large-scale quantum computers theoretically could work to solve certain problems much faster than any classic computers that use even the best algorithms to date, such as integer factorization using the Shore algorithm (which is a quantum algorithm) and modeling the quantum set of system bodies.

There are quantum actions, such as the Simon algorithm, that run faster than any possible probabilistic classical algorithm. A classic computer can in principle (with exponential resources) model a quantum algorithm, since quantum computing does not violate the Church-Turing thesis. On the other hand, quantum computers may be able to effectively solve problems that are not practically possible on classic computers.