What is a quantum computer?
Q: What is a quantum computer?
A: A quantum computer is a model of how to build a computer that uses certain ideas from quantum mechanics, such as superposition and entanglement, to perform operations on data.
Q: How does it differ from classical computers?
A: Classical computers store information in binary; each bit is either on or off. Quantum computation use qubits, which can be both on and off until a measurement is made. The state of a piece of data on a normal computer is known with certainty, but quantum computation uses probabilities.
Q: What are some potential applications for quantum computers?
A: Potential applications include cryptanalysis (breaking codes) and solving problems much more quickly than any current computer (such as Shor's algorithm).
Q: Are there other types of computers besides quantum computers?
A: Yes, there are other types of computers such as DNA computers and traditional transistors-based computers. Some computing architectures such as optical computers may also use classical superposition of electromagnetic waves.
Q: Does the Church-Turing thesis apply to quantum computing?
A: Yes, quantum computers cannot perform functions that are not theoretically computable by classical computers; they do not alter the Church-Turing thesis. However, they would be able to do many things much more quickly and efficiently than classical machines.
Q: Has large-scale quantum computing been achieved yet?
A: No, only very simple experiments have been done using qubits (quantum bits), although larger designs have been invented. Practical and theoretical research continues with interest in order to develop large-scale quantum computing capabilities for civilian and military purposes.
