The Difference Between Classical and Quantum Computing

Both classical and quantum computing process data. The difference lies in the methods and the speed of each type of computing. Although quantum computing is becoming more widely used, it will not replace classical computing; it can, however, do some things that classical computing cannot. Getting the computing power that many industries need is increasingly less possible with classical computing, which is where quantum computing comes in.

Classical Computing

A classical computer uses bits to represent data for binary processing, which has states of either 0 or 1. This eliminates any ambiguity and makes data easily predicable and replicable. A classical CPU is silicon based with transistor logic and requires external memory. Classical computing power increases linearly as a function of computing power, based on the number of transistors and bits; this allows classical computers to have good speed with parallel processing and algorithms.

A classical and quantum computer side by side

Quantum Computing

Quantum computing works using the quantum properties of atomic and subatomic particles. The primary element for computations is called a quantum bit or qubit. A quantum computer CPU is atomic, ionic, or photonic. They can be incredibly powerful while using a fraction of the energy of a classical computer. Quantum computing power also increases exponentially with each additional qubit.

Quantum computing uses two main properties from quantum physics: superposition and entanglement. Qubit processing with a quantum computer allows for multiple superposition states where a qubit can either be a 0, a 1, or both simultaneously. This property enables a quantum computer to process information significantly faster and more efficiently than a classical computer. Quantum computing also uses the principle of entanglement, where one qubit can be in a state and when coupled with another qubit, their states mimic each other without physical contact. Entanglement allows for true parallel processing.