Thank you gentlemen, I almost knew the answer, but I was a bit confused when I read :
http://en.wikipedia.org/wiki/Measurement_in_quantum_mechanics
and
http://books.google.com/books/about/Foundations_of_Quantum_Mechanics_an_Empi.html?id=KjFKZTodbEIC
In this book again for "decoherence"...
I think so.words of "collapse" and "reduction" are used in Dirac and Born interpretation of QM
and "decoherence" is used in von Neumann's measurement theory that is based on density matrix. in Dirac interpretation there is a border between quantum and classical worlds and interaction...
We know stereographic projection is conformal but it isn't isometic and in general relativity it can not be used because in this theory general transformations must be isometric. But de sitter in his model (1917) used it (stereographic projection) to obtain metric in static coordinates. How...
I don't have any problems dealing with mechanical calculations(I think), but yet I have some conceptual problems with mixed state(= statistical mixture?) and pure state in QM.
- pure state : |Φ> = 1/sqrt2 ( |↑> + |↓> )
- mixed state : ρ = 1/2 ( |↑><↑| + |↑><↑| )
What is the difference besides...
A pure quantum state is a state which can be described by a single ket vector and
A mixed state cannot be described as a ket vector. Instead, it is described by its associated density matrix (or density operator), usually denoted ρ