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Incognition
Aug11-08, 03:44 PM
I'm running a simple limiting case of a simulation with the expression:

exp(-i*H*t), where H is the hamiltonian, in this case a 2x2 matrix of zeros. Should this evaluate to 0, or to [ 1 1 ; 1 1] ?

Right now my sim uses the latter, which I'm sure is wrong. What do you think? Thanks in advance.

CompuChip
Aug11-08, 04:39 PM
By definition
\exp(A) = 1 + A + \frac{1}{2} A^2 + \frac{1}{6} A^3 + \cdots

So exp(0) = 1
with 1 the identity matrix \begin{pmatrix}1&0\\0&1\end{pmatrix}.