A quantum computer is something unreal and distant, like a guest from the future. From time to time, notes appear on scientists and their modest achievements in the field of quantum physics, but it is too early to celebrate the victory, because there are still many blank spots in this scientific branch. It is possible that in a couple of decades, quantum computers will completely replace ordinary computers familiar to us, ahead of them in mental development and leaving them far behind, but today we can only hope for that.
Scientists have already managed to develop a quantum clock that exceeds the accuracy of the current standard for measuring time by 100,000 times, so it may very well be that a breakthrough in the field of computer technology will soon be made. Today there are a huge number of developments on the creation of quantum computers. Not so long ago, four groups of scientists from Italy, Great Britain, Austria and Australia independently created the simplest model of a quantum computer, tuned to limited quantum computing.
A quantum computer can solve the problem of all modern computer technology. Now you can encode only one of the values - zero or one, but a photon at the same time can carry both values with vertical and horizontal polarization. The latest systems will be able to carry out all the calculations simultaneously, and not alternately, as conventional computers do.
A modern quantum computer, or rather its primitive model, looks like a
network of fiber optic paths on a microchip with several inputs and outputs. Separate photons are launched into the maze, at each intersection they pass through a system of beamsplitter mirrors. At this stage, the photons either reflect or pass on. It turns out that while the photon reaches the exit from the maze, it will encounter a beam splitter three times.
Quantum nature itself is very complex, so it’s almost impossible to make the right calculation, showing where the photon will come from. This is not easy to do, even if only one photon is launched into the maze. And if the task is complicated and several particles are launched, and the number of paths is increased in the maze, then it will be very difficult to make a forecast. The model invented by scientists is nothing more than a permanent matrix, the embodiment of a mathematical function.
On a modern computer, you can simulate a solution to the problem, but only on condition that several particles travel through the maze, and it is small. If the conditions are complicated, for example, to increase the number of photons or paths in the maze, then even the most powerful technique to date will not be able to make calculations .
A quantum computer created by scientists can only calculate the permanent of a matrix; it is not suitable for more complex and diverse tasks. But this is only the first step towards the invention of future technology. The task of the researchers was to demonstrate the possibility of using photonic devices that can cope with the task. The study was carried out brilliantly, so it is very possible that in the near future there will be new devices created on the basis of this technology, and they will completely replace modern computers.