Browse Definitions :
Definition

superposition

Contributor(s): Jon Kim

Superposition is the ability of a quantum system to be in multiple states at the same time until it is measured.

Because the concept is difficult to understand, this essential principle of quantum mechanics is often illustrated by an experiment carried out in 1801 by the English physicist, Thomas Young. Young's double-slit experiment was intended to prove that light consists of waves. Today, the experiment is used to help people understand the way that electrons can act like waves and create interference patterns.

For this experiment, a beam of light is aimed at a barrier with two vertical slits. The light passes through the slits and the resulting pattern is recorded on a photographic plate. When one slit is covered, the pattern is what would be expected: a single line of light, aligned with whichever slit is open.

Intuitively, one would expect that if both slits are open, the pattern of light will reflect two lines of light aligned with the slits. In fact, what happens is that the photographic plate separates into multiple lines of lightness and darkness in varying degrees.

What is being illustrated by this result is that interference is taking place between the waves going through the slits, in what, seemingly, should be two non-crossing trajectories. Each photon not only goes through both slits; it simultaneously takes every possible trajectory en route to the photographic plate.

In order to see how this might possibly occur, other experiments have focused on tracking the paths of individual photons. Surprisingly, the measurement in some way disrupts the photons' trajectories and somehow, the results of the experiment become what would be predicted by classical physics: two bright lines on the photographic plate, each aligned with the slits in the barrier. This has led scientists to conclude that superposition cannot be directly observed; one can only observe the resulting consequence, interference.

In computing, the concept of superposition has important implications for the way information will be processed and stored in the future. For example, today's classical computers process information in bits of one or zero, similar to a light switch being turned on or off.  The quantum supercomputers of tomorrow, however, will process information as qubits -- one, zero or a superposition of the two states. 

This was last updated in August 2017

Continue Reading About superposition

Join the conversation

2 comments

Send me notifications when other members comment.

Please create a username to comment.

Regarding "superposition". If my co-worker is not at his desk, he could be in any number of areas at our facility and he IS in all of those areas simultaneously until I call and locate him. is this correct? and if so, that's FASCINATING!!!
Cancel
Only if your co worker is converted to photons will this be true.
Cancel

-ADS BY GOOGLE

File Extensions and File Formats

Powered by:

SearchCompliance

  • Whistleblower Protection Act

    The Whistleblower Protection Act of 1989 is a law that protects federal government employees in the United States from ...

  • smart contract

    A smart contract, also known as a cryptocontract, is a computer program that directly controls the transfer of digital currencies...

  • risk map (risk heat map)

    A risk map, also known as a risk heat map, is a data visualization tool for communicating specific risks an organization faces. A...

SearchSecurity

  • challenge-response authentication

    In information security, challenge-response authentication is a type of authentication protocol where one entity presents a ...

  • Secure Shell (SSH)

    SSH, also known as Secure Shell or Secure Socket Shell, is a network protocol that gives users, particularly system ...

  • honeypot (computing)

    A honeypot is a network-attached system set up as a decoy to lure cyberattackers and to detect, deflect or study hacking attempts...

SearchHealthIT

SearchDisasterRecovery

  • virtual disaster recovery

    Virtual disaster recovery is a type of DR that typically involves replication and allows a user to fail over to virtualized ...

  • tabletop exercise (TTX)

    A tabletop exercise (TTX) is a disaster preparedness activity that takes participants through the process of dealing with a ...

  • risk mitigation

    Risk mitigation is a strategy to prepare for and lessen the effects of threats faced by a data center.

SearchStorage

  • exbibyte (EiB)

    An exbibyte (EiB) is a unit used to measure data capacity.

  • zebibyte (ZiB)

    A zebibyte (ZiB) is a unit used to measure computing and storage capacity.

  • tiered storage

    Tiered storage is a way to assign different categories of data to various types of storage media with the objective of reducing ...

Close