[extropy-chat] random links
scerir at libero.it
Wed Jan 31 18:24:49 UTC 2007
The air we (italians) breath
The worst possible move
Morley's theorem (1899), which says that
the three points of intersection
of adjacent trisectors of the angles of any triangle
form an equilateral triangle.
Prime numbers peep in.
"How to define the total information content
of more complex systems? In a n-dimensional Hilbert
space, one needs n^2-1 real parameters to specify
a general density matrix rho, which must be
hermitean and have Tr(rho)=1. Since measurements
within a particular basis set can yield only n-1
independent probabilities (the sum of all probabilities
for all possible outcomes in an individual experiment
is one), one needs n+1 distinct basis sets
to provide the required total number of n^2-1
independent probabilities. Ivanovic (1981) showed
that the required number n+1 of unbiased basis sets
indeed exists if n is a prime number."
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