A quantum computer uses quantum mechanical phenomena, such as entanglement and superposition to process data. Quantum computation aims to use the quantum properties of particles to represent and structure data using quantum mechanics to understand how to perform operations with this data.
The quantum mechanical properties of atoms or nuclei allow these particles to work together as quantum bits, or qubits. These qubits work together to form the computer’s processor and memory and can can interact with each other while being isolated from the external environment and this enables them to perform certain calculations much faster than conventional computers. By computing many different numbers simultaneously and then interfering the results to get a single answer, a quantum computer can perform a large number of operations in parallel and ends up being much more powerful than a digital computer of the same size.
A quantum nanocomputer would work by storing data in the form of atomic quantum states or spin. Technology of this kind is already under development in the form of single-electron memory (SEM) and quantum dots. By means of quantum mechanics, waves would store the state of each nanoscale component and information would be stored as the spin orientation or state of an atom. With the correct setup, constructive interference would emphasize the wave patterns that held the right answer, while destructive interference would prevent any wrong answers.
The energy state of an electron within an atom, represented by the electron energy level or shell, can theoretically represent one, two, four, eight, or even 16 bits of data. The main problem with this technology is instability. Instantaneous electron energy states are difficult to predict and even more difficult to control. An electron can easily fall to a lower energy state, emitting a photon; conversely, a photon striking an atom can cause one of its electrons to jump to a higher energy state.
I promise to write a series of articles on quantum issues very shortly...