What is entanglement? - Definition from WhatIs.com
Part of the Electronics glossary:

Entanglement is a term used in quantum theory to describe the way that particles of energy/matter can become correlated to predictably interact with each other regardless of how far apart they are.

Particles, such as photons, electrons, or qubits that have interacted with each other retain a type of connection and can be entangled with each other in pairs, in the process known as correlation. Knowing the spin state of one entangled particle - whether the direction of the spin is up or down - allows one to know that the spin of its mate is in the opposite direction. Even more amazing is the knowledge that, due to the phenomenon of superposition, the measured particle has no single spin direction before being measured, but is simultaneously in both a spin-up and spin-down state. The spin state of the particle being measured is decided at the time of measurement and communicated to the correlated particle, which simultaneously assumes the opposite spin direction to that of the measured particle. Quantum entanglement allows qubits that are separated by incredible distances to interact with each other immediately, in a communication that is not limited to the speed of light. No matter how great the distance between the correlated particles, they will remain entangled as long as they are isolated.

Entanglement is a real phenomenon (Einstein called it "spooky action at a distance"), which has been demonstrated repeatedly through experimentation. The mechanism behind it cannot, as yet, be fully explained by any theory. One proposed theory suggests that all particles on earth were once compacted tightly together and, as a consequence, maintain a connectedness. Much current research is focusing on how to harness the potential of entanglement in developing systems for quantum cryptography and quantum computing.

In 1997, Nicholas Gisin and colleagues at the University of Geneva used entangled photons to enable simple - but instantaneous - communication over a distance of seven miles.

This was last updated in April 2006
Posted by: Margaret Rouse

Related Terms

Definitions

  • signature analysis

    - Signature analysis has two meanings. It can involve scrutinizing human signatures in order to detect forgeries and it can be a troubleshooting technique in which an AC signal with a specific wavef... (WhatIs.com)

  • bioprinting

    - Although bioprinting is still in the experimental stage and is currently used primarily in scientific study rather than applied science, the possibility of creating functional replacement tissues o... (WhatIs.com)

  • flash storage

    - Flash storage, based on flash memory, is used for data repositories, storage systems and consumer devices, such as USB drives, smartphones and solid-state drives. Flash-based storage is faster than... (WhatIs.com)

Glossaries

  • Electronics

    - Terms related to electronics, including definitions about electrical components and words and phrases about computers, laptops parts, digital cameras, televisions and home appliances.

  • Internet applications

    - This WhatIs.com glossary contains terms related to Internet applications, including definitions about Software as a Service (SaaS) delivery models and words and phrases about web sites, e-commerce ...

Ask a Question About entanglementPowered by ITKnowledgeExchange.com

Get answers from your peers on your most technical challenges

Tech TalkComment

Share
Comments

    Results

    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.