Quantum computers functionally use properties of quantum microparticles. In classical computers, information is represented in the form of bits (0 and 1) where one information can be either 0 or 1 in one moment. In quantum computers, the basic units of operation are qubits, which use the quantum superposition phenomenon and other quantum properties for operation over information. What this means is that a qubit can have multiple states of zero and one (0, 1, 01, 00, 10, 11), since each of these states can be in the superposition, which gives the qubit multidimensionality. Interesting fact about the quantum bit is that it can have a possible state (0, 1, 01, 00, 10, 11) only if we do not observe it. The moment we begin to look at it, it transforms into a state of the ordinary bit, where its possible state is either zero or one. What this means is that quantum calculations take place outside our perception, and the moment we get involved in requesting that information that the quantum computer processed, we get only ordinary bit as output. In some opinions, this happens among other things because the human brain and body are not ready or accustomed to the superposition state of the particle. For this phenomenon, we can say that it is a shyness of the qubit itself in question.
An essential feature of a quantum computer is the property of an electron called a spin. Spin is a feature of an electron that allows it to rotate itself around its axis but what is more, gives qubit multidimensionality when the particle is in superposition. According to the binary logic, two states or more precisely two directions of the spin are defined, which are opposite, where one is zero and the other one. With the help of spin, we can create computer memory.
A quantum computer with 500 qubits can have 2 to the 500th power states simultaneously (n qubit - 2 to the nth power states).
The possibilities of these computers are so immense that they can solve even the most complex mathematical problems very quickly. Incomparably faster than conventional computers. One example of this is the Shore Quantum Algorithm, which may be the fastest way to factorize numbers; it can without any problems break any RSA code that is in use today. A quantum computer could reveal all the secrets of this world in only twenty minutes.
Example of number factoring:
Factoring in mathematics is the decomposition of an object (number, polynomial, or matrix) into
the product of some other objects, or factors, which when multiplied by each other, give the
original number. An example of this is the very first task that a quantum computer had done
when it factorized number 15 in the form 3 x 5. For complex operations and factoring
calculations, quantum computers only need 20 minutes, whereas a classical computer would
need light years to complete the same task.
Classical computers can solve operations that require numbers in lists to be multiplied by each other. They do this by solving individual operations. Hence to solve complex operations, they need to calculate many operations individually, and because of that, they require considerable processor power. Taking into account that silicon is a limited substance because of its chemical composition, this matrix enters its red zone and cannot deal with complicated mathematics. A quantum computer solves this problem. So, with ordinary computers, operations are solved by standard procedures, whereas the quantum computer solves the same operations from the superposition. How so? Let's take the numbers 1, 2, 3, 4, 5 and number 7 as a multiplier. The classical computer does the following: 1 x 7, 2 x 7, 3 x 7, 4 x 7, 5 x 7, and this is its possible state. The quantum computer puts all five numbers into a sequence (in a superposition of qubit) and at the same time multiplies all of them with 7. With simple tasks like this the difference between the use of a classical and quantum computer may not seem like much, but what did quantum computer do? It accelerated the processing time, so in this case, it accelerated the operation five times. When it comes to complex tasks such as when 1, 2, 3, 4, 5, need to be multiplied by 2, 3, 4, 5, 6, 3, 4, 5, 6, the classical computer will start procedurally again, and it will need much time again, while the quantum computer will put the first set of numbers in an abstract sequence, and at the same time do the same with the second set (put them in an abstract sequence). So, instead of multiplying each number from the first list by each number on the second list individually, it will by putting a second set in a superposition define a common index that will actually be a quantum state which will allow the first series to be multiplied with the second, and by doing this quantum bit will solve all of the complex operations that bit would procedurally solve in one operation. This tells us that the quantum bit will solve any of our ideas in an abstract sense as long as we do not observe it. The moment we begin to look at it, the output will be either zero or one as the final value.
Perhaps this is not the clearest explanation when you understand how classical physics works and you do not allow quantum physics actually to become a postulate, but we will try to explain what is happening here.
The possible state of the quantum bit is defined by spins, superposition, and mixing of qubits. We have spin (up, down) – direction, superposition (0, 1, 0, 01, 00, 10, 11) and mixing (up 1, 0, 01, 00, 10, 11) (and) (down, 1, 0, 01, 00, 11). This is the simplest setup of a qubit. Now, take what you see and mix it in all possible directions and dimensions and you will get the quantum bit in the superposition as a result. What has happened is that a quantum bit can be any value that exists in space and time (as a possible state). This means that the rules of quantum physics are volatile because in the superposition of one particle every principle of thermodynamics is undermined (for example the first thermodynamic law on the conservation of energy). Theoretical, at least for now, but the accurate setup is Maxwell's demon, where there are two containers in one container, between them is some barrier and in the middle the door. Also, we have a demon who opens and closes this door. Since the principles of thermodynamics function in an autonomous state, the demon disrupts this autonomy, and there is nothing more to dismiss or to undermine the thermodynamic postulate. However, let's take as an example that we can hypothetically automate this process of opening and closing the door and leave the container in an autonomous state. In these two containers, we have some particles, ones are faster (have a higher temperature) and others are slower (have a lower temperature), and since the demon is standing outside the autonomy of the container itself, he records the speed of each particle. All the faster particles from a container (with slower particles) are moved into the container where the particles are faster, and all the slower particles from a container (with faster particles) are moved into the container where the particles are slower. This results in a higher temperature in the container where the particles are faster and the lower temperature where the particles are slower. This process undermines the first law of thermodynamics as this law states that when a body that has a lower temperature is near a body that has a higher temperature, there will be an exchange of energy between them (the heat from the hotter body will pass to the cooler body). In this case, there is a paradox of Maxwell's demon.
We cited this example only to show that quantum physics undermines all possible laws of classical physics and that it is a paradox in every sense of the word. Let's go one step further. We will take an example of a bucket of two colors of sand, yellow sand and gray sand. We will now mix the sand. At the moment when we stir the sand, there is no reversible process to return it all as it was. We will go back to Maxwell's demon and see how it is possible to defy irreversibility, or in other words how we can perform a reversible process (at least theoretically). This theory tells us, if true, that quantum physics has the power of reversibility, which could decrypt the most complex crypto algorithms. So let's go back to the container with a barrier in the middle and a small door which divide this container into two sections. We said that we have faster and slower particles and that we have a demon on the side that observes, assigns values to and moves particles from one side to the other, and vice versa. We want to create a reversible process. We'll give the demon a notebook and a pencil, but he will not be able to use an eraser. The only condition is that he records every value of each particle, that his pencil is never used up, and that the notebook has an infinite number of pages. He would start to record the values of the particle and, in terms of speed, change the positions of that particle (moving from one section of the container to another and vice versa). If he were to use an eraser and wipe only one particle’s velocity measurement, this would remove the possibility of returning everything as it was (the process would be irreversible). However, theoretically, if he was to do everything correctly and also defy the law of thermodynamics, in case he wanted to return everything to how it was, to return everything to the autonomous state, and also to put back in action the thermodynamic law, he would be able to do so and continue his observation. As a result, the process would be fully reversible, and this is where the actual power of quantum physics is.
Conclusion. Super quantum computers could in a short time reveal every possible secret (all TOP SECRET tags would become PUBLIC) because each asymmetric, and also symmetric algorithm could be broken in short time, and all tags under a veil of secrets would be uncovered. That would be a significant advance for humankind. FULLSTOP.