QUANTUM METAPHYSICS - E-thesis

In addition to conjugated variables, a new coherence or internal relationship between the parts of
a system is manifested by non-locality. In quantum mechanics, particles which once belonged
together but are now located far apart are correlated with each other, in a manner which
traditional theories are not able to predict by presuming that reality consists of locally-interacting
separated parts. 534 This holistic feature of quantum systems, which Albert Einstein criticised via
his EPR paradox argument, has now been the subject of experimental confirmation. In the 1990s,
experiments conducted on interference phenomena between different states of individual
particles gave rise to increased discussion of non-localised entanglement. 535
If a multi-particle situation can be recorded as the result of individual particle states, the quantum
states of the particles are independent of each other. If this is so, each particle can be thought of
as being in its own position in Hilbert space, and these states can then be measured without the
measurement affecting other particles. On the other hand, if the states are entangled, a multiparticle
state does not consist of individual particle states and a measurement which apparently
concerns a single particle will actually affect the state of the whole system: measurement of
Particle 1 followed by measurement of Particle 2 will not be the same thing as measurement of
Particle 2 followed by measurement of Particle 1. The best-known example of entanglement is
the two double-state particles which form an EPR pair.
533 Heisenberg 1955, 25-27.
534 Omnes 1999, 228-230.
535 See Quantum Challenge.
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