Difference between Quantum Computer vs Classical Computer

Quantum Computer vs Classical Computer-Difference between Quantum Computer and Classical Computer

This page compares Quantum Computer vs Classical Computer and mentions difference between Quantum Computer and Classical Computer.

Classical Computer	Quantum Computer
It is large scale integrated multi-purpose computer.	It is high speed parallel computer based on quantum mechanics.
Information storage is bit based on voltage or charge etc.	Information storage is Quantum bit based on direction of an electron spin.
Information processing is carried out by logic gates e.g. NOT, AND, OR etc.	Information processing is carried out by Quantum logic gates.
Circuit behaviour is governed by classical physics.	Circuit behaviour is governed explicitly by quantum mechanics.
Classical computers use binary codes i.e. bits 0 or 1 to represent information.	Quantum computers use Qubits i.e. 0, 1 and both of them simultaneously to run machines faster.
Operations are defined by Boolean Algebra.	Operations are defined by linear algebra over Hilbert Space and can be represented by unitary matrices with complex elements.
No restrictions exist on copying or measuring signals	Severe restrictions exist on copying and measuring signals
Circuits are easily implemented in fast, scalable and macroscopic technologies such as CMOS.	Circuits must use microscopic technologies that are slow, fragile and not yet scalable e.g. NMR (Nuclear magnetic resonance).