The origin of nonlocality in quantum physics can be traced back to the fundamental principles of the theory. Quantum mechanics, which is the framework that describes the behavior of particles at the microscopic scale, introduced the concept of nonlocality to explain certain experimental observations.
Nonlocality refers to the phenomenon where the properties of two or more particles become intertwined in such a way that the state of one particle cannot be described independently of the state of the others, regardless of the distance between them. This behavior is often referred to as "entanglement."
The concept of entanglement was first proposed by Erwin Schrödinger in 1935 as a way to describe a peculiar aspect of quantum mechanics. According to quantum theory, particles such as electrons, photons, or atoms can exist in a superposition of multiple states, meaning they can be in different states simultaneously. When two or more particles interact and become entangled, their states become correlated in a way that the measurement of one particle's property instantaneously determines the state of the other particle, regardless of the spatial separation between them.
This instantaneous correlation between entangled particles, regardless of distance, violates our classical intuition about causality and locality. It is known as nonlocality because the effects of measurement or manipulation of one particle appear to propagate faster than the speed of light, which contradicts the principles of special relativity.
However, it is important to note that nonlocality in quantum mechanics does not allow for faster-than-light communication or signaling. While the measurement of one entangled particle appears to instantaneously affect the state of the other particle, this effect cannot be used to transmit information faster than the speed of light. The correlations are probabilistic, and it is only after comparing measurement results from many entangled particles that statistical patterns emerge.
The origin of nonlocality in quantum physics is deeply rooted in the mathematical formalism and principles of the theory. It is a fundamental aspect of quantum mechanics that has been extensively confirmed by experimental tests, including Bell's theorem and various tests of entanglement.