You need to define a new combined quantum number, which is changed by the training and lowering operators for both types of particles.
On 17 Jan 2017, at 08:54, Michele Dolfi dolfim@phys.ethz.ch wrote:
I hope somebody else could give you a better answer, but I don’t think this is possible out of the box, and I’m not 100% sure it is at all possible in the way you think about it.
What I would try is away to play around with a new model definition where you make a composite quantum number explicit. The "fermion Hubbard” and “alternative fermion Hubbard” could be of inspiration for how to conserve N and/or Sz instead of Nup and/or Ndown.
Best, Michele
-- ETH Zurich Dr. Michele Dolfi Institute for Theoretical Physics HIT G 32.4 Wolfgang-Pauli-Str. 27 8093 Zurich Switzerland
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On Jan 17, 2017, at 4:10 PM, Axel Gagge <axel.gagge@fysik.su.se mailto:axel.gagge@fysik.su.se> wrote:
Hello, I just wanted to ask if it is possible to preserve a combination of quantum numbers such as the total number of excitations:
N = \sum_{bosonic sites} n_j + 1/2 \sum_{spinful sites} s_z
and what the syntax for this would be? I guess that one option would be to define a new quantum number and let Splus raise it by 1/2 but I just thought that I would check this with you first!
Otherwise, thank you for an excellent library! I have had no problems so far with the new release.
Thanks, /Axel Gagge First year PhD Student, Stockholm University
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