Dear Klaus,
It is straightforward to implement such updates in the looper. A tricky thing is: how to prepare an initial configuration. Also, I'm not sure if the ergodicity is fulfilled by such updates.
Best, Synge
On 2010/08/06, at 6:43, Klaus Larjo wrote:
Dear all,
I'm studying the spin-1/2 XXZ spin chain. As I understand it, among other things the loop algorithm computes the partition function Z = Tr <n| e^(-bH) |n>, with b the inverse temperature, |n> a basis vector, and Tr a sum over that basis.
However, I would like to compute matrix elements of the form <n| e^(-bH) |m>, where |n> and |m> are basis vectors to be specified by me. Is this possible to do via the looper algorithm, or any of the other ALPS algorithms based on worldline QMC?
Thank you, Klaus