Nonlocality

In physics, nonlocality or action at a distance is the direct interaction of two objects that are separated in space without an intermediate agency or mechanism. It is normally modelled as events that take place in a field, such as a gravitational field.

Isaac Newton (1642-1727) considered gravity-action-at-a-distance "so great an Absurdity that I believe no Man who has in philosophical Matters a competent Faculty of thinking can ever fall into it". Quantum nonlocality refers to what Einstein called the "spooky action at a distance" of quantum entanglement.

Nonlocality may also refer to:

• Nonlocal Aharonov–Bohm effect, a quantum mechanical phenomenon in which an electrically charged particle is affected by an electromagnetic field, despite the fact that the field is zero in the region concerned
• Nonlocal Lagrangian, a Lagrangian that contains terms that are nonlocal in the fields $\ \phi (x)$
• Nonlocal generalisation of the Londons' equation due to Pippard

See also

• Principle of locality
• Relative locality
• Synchronicity
• Wheeler-Feynman absorber theory