Quantum Tantrums

Why Quantum Statistics?

Why Quantum Statistics?

Jul 14, 2011

Consider the following scenario. An initial measurement indicates that two indistinguishable particles – particles of the same type, carrying no kind of identity tag – are headed northward and southward, respectively. The next (relevant) thing that is indicated by a measurement is that two particles of exactly the same type are headed eastward and westward, respectively. We also assume that the scattering is elastic – no particles are created or annihilated in the meantime – and that the pair of outgoing particles is in some sense the same as the pair of incoming particles: no other particle has entered or left the scene in the meantime.

ujm

ujm

Born and raised in Germany, I joined the Sri Aurobindo International Centre of Education (SAICE), Pondicherry, India, as an undergraduate student in 1972. From 1974 to 1978 I studied physics at the University of Göttingen, Germany, and at the Indian …
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To Be Is To Be Measured (Part 1)

To Be Is To Be Measured (Part 1)

Quantum mechanics allows us to perform the following experiment (see the article by David Mermin in Physics Today Vol. 38 No. 4):

A Simple Derivation Of Heisenberg's Uncertainty Principle

A Simple Derivation Of Heisenberg's Uncertainty Principle

In his recent blog post "The World Is Not Woven From Real Stuff", Sascha Vongehr wrote:Some merely claim that we need quantum mechanics so that the electron does not fall into the atom’s nucleus. Any classical electric charge would spiral into the atom's nucleus. The material that they make up would collapse.... Well, how convincing is this argument? Does it convince you? It would not convince me without a severe dose of already knowing at least a bunch of electromagnetism. Why could there not be some other, more intuitive explanation of why atoms do not collapse?