Quantum computing, at least in theory, has been spoken for several decades. Modern types of machines using non-classical mechanics to process potentially unimaginable amounts of data have become a major breakthrough. According to the developers, their implementation turned out to be perhaps the most complex technology ever created. Quantum processors operate at the levels of matter, which mankind learned only 100 years ago. The potential for such computing is enormous. Using the bizarre properties of quanta will speed up the calculations, so many tasks that classical computers can’t afford at present will be solved. And not only in the field of chemistry and materials science. Wall Street is also showing interest.
Investing in the future
CME Group has invested in Vancouver-based company 1QB Information Technologies Inc., which develops software for quantum-type processors. According to investors, such calculations are likely to have the greatest impact on industries that work with large volumes of time-sensitive data. An example of such consumers are financial institutions. Goldman Sachs invested in D-Wave Systems, while In-Q-Tel is funded by the CIA. The first produces machines that do what is called “quantum annealing,” that is, it solves low-level optimization problems using a quantum processor. Intel is also investing in this technology, although it considers its implementation a matter of the future.
Why is this needed?
The reason quantum computing is so exciting lies in its perfect combination with machine learning. This is currently the main application for such calculations. In part, this is a consequence of the very idea of a quantum computer - the use of a physical device to search for solutions. Sometimes this concept is explained on the example of the game Angry Birds. To simulate gravity and the interaction of colliding objects, the CPU of the tablet uses mathematical equations. Quantum processors turn this approach upside down. They “throw” several birds and watch what happens. The task is written in the microchip : these are birds, they are thrown, what is the optimal trajectory? Then all possible solutions are checked, or at least a very large combination of them, and an answer is given. In a quantum computer, the problem is not solved by mathematicians; instead, the laws of physics work.
How does it work?
The main building blocks of our world are quantum-mechanical. If you look at the molecules, the reason they are formed and remain stable is the interaction of their electronic orbitals. All quantum mechanical calculations are contained in each of them. Their number is growing exponentially in the number of simulated electrons. For example, for 50 electrons there are 2 to the 50th degree of possible options. This is a phenomenally large number, so it cannot be calculated today. Connecting information theory to physics can indicate a way to solve such problems. A 50-qubit computer can do it.
Dawn of a new era
According to Landon Downs, president and co-founder of 1QBit, a quantum processor is the ability to use the computing power of the subatomic world, which is of great importance for obtaining new materials or creating new drugs. There is a transition from a paradigm of discovery to a new era of design. For example, quantum computing can be used to model catalysts that can extract carbon and nitrogen from the atmosphere, and thus help stop global warming.
At the forefront of progress
The community of developers of this technology is extremely excited and busy. Teams around the world in startups, corporations, universities, and government race labs are building machines that use different approaches to processing quantum information. Superconducting qubit chips and qubits on trapped ions have been created, which researchers from the University of Maryland and the US National Institute of Standards and Technology are engaged in. Microsoft is developing a topological approach called Station Q, whose goal is to use a non-Abelian anion, the existence of which has not yet been conclusively proven.
Year of probable breakthrough
And this is just the beginning. As of the end of May 2017, the number of quantum-type processors that definitely do something faster or better than a classic computer is zero. Such an event will establish "quantum superiority", but so far it has not happened. Although it is likely that this can happen this year. Most insiders say the go-ahead group is Google, led by physics professor at the University of California, Santa Barbara, John Martini. Its goal is to achieve computational excellence with a 49-qubit processor. By the end of May 2017, the team successfully tested a 22-qubit chip as an intermediate step towards disassembling a classic supercomputer.
How did it all start?
The idea of using quantum mechanics to process information for decades. One of the key events occurred in 1981, when IBM and MIT jointly organized a conference on computational physics. The famous physicist Richard Feynman proposed building a quantum computer. According to him, for modeling should use the means of quantum mechanics. And this is a wonderful task, because it does not look so simple. For a quantum processor, the principle of operation is based on several strange properties of atoms - superposition and entanglement. A particle can be in two states at the same time. However, when measured, it will appear in only one of them. And it is impossible to predict in which, except from the standpoint of probability theory. This effect underlies the thought experiment with the Schrödinger cat, which is in the box both alive and dead until the observer sneaks a glance there. Nothing in everyday life works this way. Nevertheless, about 1 million experiments conducted since the beginning of the twentieth century show that superposition does exist. And the next step will be figuring out how to use this concept.
Quantum processor: job description
Classic bits can take the value 0 or 1. If you pass their line through the “logic gates” (AND, OR, NOT, etc.), you can multiply numbers, draw images, etc. The qubit can take values 0, 1 or both at the same time. If, say, 2 qubits are entangled, then this makes them completely correlated. A quantum type processor may use logic gates. T. n. Hadamard's valve, for example, puts the qubit in a state of perfect superposition. If superposition and intricacies are combined with smartly located quantum gates, then the potential of subatomic calculations begins to unfold. 2 qubits allow you to explore 4 states: 00, 01, 10 and 11. The principle of operation of the quantum processor is such that the logical operation makes it possible to work with all positions at once. And the number of available states is 2 in the degree of the number of qubits. So, if you make a 50-qubit universal quantum computer, then theoretically you can explore all 1,125 quadrillion combinations at the same time.
Kudity
The quantum processor in Russia is seen a little differently. Scientists from the Moscow Institute of Physics and Technology and the Russian Quantum Center created “kudits”, which are several “virtual” qubits with different “energy” levels.
Amplitudes
A quantum-type processor has the advantage that quantum mechanics is based on amplitudes. Amplitudes are similar to probability, but they can also be negative and complex numbers. So, if you need to calculate the probability of an event, you can add up the amplitudes of all kinds of options for their development. The idea of quantum computing is to try to adjust the interference pattern so that some paths to the wrong answers have a positive amplitude, and some have a negative one, and therefore they would cancel each other out. And the paths leading to the correct answer would have amplitudes that are in phase with each other. The trick is that you need to organize everything without knowing in advance which answer is correct. So the exponentiality of quantum states in combination with the interference potential between positive and negative amplitudes is an advantage of calculations of this type.
Shore Algorithm
There are many tasks that the computer is not able to solve. For example, encryption. The problem is that it is not so easy to find prime factors of a 200-digit number. Even if the laptop works with excellent software, you may have to wait years to find the answer. Therefore, another milestone in quantum computing was the algorithm published in 1994 by Peter Shore, now a professor of mathematics at MIT. His method is to search for multipliers of a large number using a quantum computer, which then did not exist. In essence, the algorithm performs operations that point to areas with the correct answer. The following year, Shore discovered a method for quantum error correction. Then many realized that this is an alternative way of computing, which in some cases can be more powerful. Then there was a surge of interest on the part of physicists in the creation of qubits and logical gates between them. And now, two decades later, humanity is on the verge of creating a full-fledged quantum computer.