A Quantum Glossary


Here are some of the terms that we’ve encountered.


This is the spreading out of a wave as it encounters the edge of a barrier.
Think about how the light in a corridor spreads out into a dark room whose door is slightly ajar.


A phenomenon whereby two or more quantum objects cannot be mathematically described separate from each other. It is associated with strange quantum correlations, irrespective of spatial distance separating the objects.


This is when waves can add up and/or cancel each other out.
If waves are in phase, they add to each other. If they are out of phase, they cancel each other.

Quantum algorithm

Definition: A sequence of computational steps for a quantum computer to follow.

Quantum Mechanics

The mathematical and physical theory developed to describe the behaviours of quantum objects and systems.


A qubit is a quantum bit. A quantum bit is the basic unit of quantum information and essentially, the building blocks of quantum computers.


The state of a physical object is simply its description in a particular context/setting.


The ability of quantum objects to be in two or more, measurably distinct states at the same time.


The mathematical function that describes the state of a quantum object/system.

Wave-function collapse

This refers to a phenomenon that occurs when quantum objects/systems are observed or measured. Wave-function collapse is the reduction of a superposed state to one of the measurable states.

Wave-particle duality

The ability of tiny objects to display both wave-behaviour and particulate behaviour in different experimental settings. The idea of wave-particle duality revolutionized Physics.