How do quantum computers work?
Extensive progress has recently been made in the world of technology and the construction of high-speed computational processors seeking to improve supercomputers, but these computers are yet to become able to solve some complex problems.
The hardware of the computer works on an electric component known as a transistor The performance of conventional computers is fundamentally based on saving binary digits in their storage and performing processing and saving on them using switches called transistors.
transistor is the most essential circuit component in electronics which is used to disconnect and amplify signals and can regulate and control current and voltage; in other words, it acts as a gateway or switches for signals.
The transistor is either on or off creating the two states of zero and one one just as each computer bit can be in either mode of on or off (zero or one). Long strings of these zeros and ones are used to save characters, numbers, and symbols based on ASCII code principles.
Computers perform the processing and calculation of the bits using the logic gates made out of transistors. A logic gate measures the mode of a bit and saves it in the random access memory, then performs calculations based on an algorithm to change it into a new state. An algorithm is made up of several logic fates forming an electronic circuit together, by which the desired calculations are made.
The shrinking of transistors is among the problems posed to the process of development. Despite the increased number of transistors which has brought about increased memory and speed in computers, there are still several complex problems the supercomputers are unable to solve. The calculations thus need to be taken to the quantum world.
Old transistors follow the rules of classic physics. Reducing the size of transistors to atomic dimensions would result in these rules standing no longer and demand the use of more complex quantum physics laws.
Large corporations are investing efforts in building transistors in atomic dimensions which would involve quantum physics laws such as quantum tunneling 1 . This tunneling would not be favorable for the computational chip since the movement of electrons would interfere with it. Quantum physics and its laws thus emerge and have to be followed in extremely small dimensions.
Quantum computers are specific types of computers using certain algorithms to perform complex calculations. They consider a physical phenomenon in a specific state based on quantum physics laws and determine a new state of the phenomenon after information processing.
The idea for quantum computers was first introduced in 1982. Richard Feynman, the world-renowned physicist, introduced the use of quantum mechanics principles in a basic machine to perform calculations which were later developed by other scientists.
The characterizing feature of conventional computers such as bits, algorithms, and logic gates are present in quantum computers as well.
Physicists managed to generate a quantum unit of information called a Qbit or quantum bit which is the processing unit in quantum computers using quantum phenomena. Contrary to bits which can only have a value of either one or zero, a Qbit can hold any other given value between zero and one. That is, a Qbit is a superposition of the zero and one base state which must be measured to determine its state.
This superposition would mean that a quantum computer can process information or Qbits simultaneously and in real-time, which extremely increases the calculation speed compared to a conventional computer.
[1] In the quantum state, unlike the classical state, the particle can cross the potential barrier and be present on the other side of the barrier, indicating the dual wave-particle property.
The progress made in the field of computer sciences and computations has resulted in special attention to quantum computers.
Given that the information is saved as bits, changing the information in the processing component of the computer results in energy consumption and leads the system to warp up.
The processing and calculation processes have been recommended to become reversible to prevent energy loss. . This would mean that the inputs should be retrievable based on the output information which requires the logic gates to work reversibly.
In short, quantum computers perform complex calculations faster and use less energy by performing them reversibly.
There is an operator called time evolution in quantum physics which also goes by the name of reversal operator. This operator is unitary and performs a one-by-one mapping over a specific period. In other words, it turns one quantum state into another.
His mapping is performed by the quantum gate in quantum computers and is reversible.
To define Qbits, quantum computers need a binary physical system in small quantum dimensions such as the upper and lower spin of an electron or an atom or ion change of state whose quantum state alters as a result of a physical phenomenon. Quantum systems in extremely small dimensions are prone to noise and have a high error rate, which means they suffer disturbance and their state changes constantly.
The setting of a Qbit (atom, ion, electron spin, etc.) in a specific state would be equal to the storage of information, and changing its state would be the equivalent of performing processing on the Qbit.
The quantum state of a Qbit creates a difficult and complex situation in reaching thesuperconducting state (close to absolute zero temperature). The system should thus be isolated and the interfering factors must be eliminated to control the system status and set it so that the Qbits can be defined and processed.
This would require great expenditures on specific techniques such as creating a vacuum or cooling the system (such as superconductors).
The quantum processor should also be kept away from electromagnetic vibrations to prevent noise, for which purpose it is stored in a specific container.
Given the mentioned issues and the particular conditions governing quantum computers, it would be unlikely for them to replace conventional computers considering that they need special algorithms to perform besides their other complex conditions.
The need for quantum computers still stands given the long time spent searching large databases The growth and development of cryptography and quantum communications owe to the development of these computers, and their determining and crucial role of physics in the future of this field of science is crystal clear.
[1] In the quantum state, unlike the classical state, the particle can cross the potential barrier and be present on the other side of the barrier, indicating the dual wave-particle property.