Dear Matthias, Thank You. I wil try this approach. Kind Regards, Mateusz Łącki On Aug 3, 2012, at 4:52 PM, Matthias Troyer wrote:

Dear Mateusz,

The trick that I would do is to introduce another, additional, quantum number where minimum and maximum are nL + nR. Then you can put a constraint on that quantum number.

Matthias

On Aug 3, 2012, at 5:39 AM, Mateusz Łącki <mateusz.lacki@gmail.com> wrote:

...

Dear All, I want to define a model for boson-boson mixture to be run by a worm code. I have two types of bosons: of type L and type R. I would like to be able to consider a conservation of total number of bosons that is : nL + nR = const. What should I put into "contraint":

<CONSTRAINT quantumnumber="N" value="N_total"/>

?

I would like to have something like <CONSTRAINT quantumnumber="NL + nR" value="N_total"/>

An option is probably to redefine quantum numbers

from: nR and nL into nA and nB

by nA = (nR + nL) and nB = (nL-nR)

(now nA is >=0 and nB is arbitrary)

of course one would have to change creation and annihilation operators, all observables... this i why I would like to avoid it.

Regards, Mateusz Łącki