Dear Luca,
That is an easy task: Just put a different parameter in your function.
1) Put the "salt" as a parameter in your onsite function and not in
make_system
def Onsite(site, salt="1"):
……
……
2) when you do your calculation, use params:
params={"disorder"="1", B=2, Phi=4}
for i in range(100):
params["disorder"]=str(i)
wave=kwant.wave_function(syst, params=params)
#then calculate whatever you want for this configuration
I hope this helps
Adel
On Mon, Feb 3, 2020 at 11:23 PM Luca Lepori <llepor...@gmail.com> wrote:
> Dear Adel and Joe,
>
> thanks again for your useful reply.
>
> If I understand correctly, then I am not sure
> how to simulate the physics of disorder.
>
> Indeed, that task requires to create various
> (in principle infinite in number) configurations,
> measure some physical quantity on each of them, and then
> to take the average of all these measurements on the created
> configurations.
>
> How can I create the different configurations ?
> Starting e.g. from the piece of code
>
>
> ------------------------------------------------------------------------------------------------
>
> t = 1
> Delta = 1
> L = 50
> W = 1
> (salta = ?)
>
> mub = 3
> systb = kitaev(L,t,mub,Delta,W,salt)
> systb = systb.finalized()
> hamatb = systb.hamiltonian_submatrix(sparse = False)
> evalsb, evecsb = la.eigh(hamatb)
>
>
> ------------------------------------------------------------------------------------------------
>
> is it sufficient to add a For cycle on the value of salt ?
> Say, from 1 to Nmax, where Nmax is the number of configurations
> that I want to consider ?
>
> Thank you very much again
>
> L.
>
> Il giorno lun 3 feb 2020 alle ore 11:48 Abbout Adel
> <abbout.a...@gmail.com> ha scritto:
> >
> > Dear Luca,
> >
> > With the parameter salt (which can be a number or a string), you will be
> sure that each time you call your system (or hamiltonian) with the same
> parameter salt, you will have the same configuration: this means that the
> potential is random from one site to another, but the overall configuration
> does not change when you call your system many times. If you use the usual
> random function from numpy, you will have a different random configuration
> each time you call your system.
> >
> > I hope this helps,
> > Adel
> >
> > On Mon, Feb 3, 2020 at 12:00 AM Luca Lepori <llepor...@gmail.com> wrote:
> >>
> >> Dear Joe,
> >>
> >> thank you very much for your fast and compelling reply.
> >>
> >> Exploiting your advice, that means writing
> >>
> >>
> -----------------------------------------------------------------------------------------------
> >>
> >> def onsite(site, salt):
> >>
> >> return uniform(repr(site))
> >>
> >>
> >> def kitaev(L ,t, mu, Delta, W, salt) :
> >>
> >> syst = kwant.Builder()
> >> lat = kwant.lattice.chain(norbs=2)
> >>
> >> syst[lat(0)] = -(1/2)*(mu + W*(2*onsite(lat(0), salt) - 1))*pauli3
> >>
> >> for i in range(1,L):
> >>
> >> syst[lat(i)] = -(1/2)*(mu + W*(2*onsite(lat(i), salt) -
> 1))*pauli3
> >>
> >>
> >> syst[lat(i), lat(i - 1)] = -(t/2)*pauli3 + 1j*(Delta/2)*pauli2
> >>
> >>
> >> return syst
> >>
> >>
> -----------------------------------------------------------------------------------------------
> >>
> >> the code actually works, in the sense that no errors occur in the output
> >> of the calling string
> >>
> >>
> -----------------------------------------------------------------------------------------------
> >>
> >> t = 1
> >> Delta = 1
> >> L = 50
> >> W = 1
> >> salt = 1
> >>
> >> mub = 3
> >> systb = kitaev(L,t,mub,Delta,W,salt)
> >> systb = systb.finalized()
> >> hamatb = systb.hamiltonian_submatrix(sparse = False)
> >> evalsb, evecsb = la.eigh(hamatb)
> >>
> >>
> -----------------------------------------------------------------------------------------------
> >>
> >> However, I still do not get the role of the parameter "salt" (here
> >> above I defined it conventionally
> >> salt = 1): how do I have to set it ?
> >>
> >> In the previous discussion page
> >>
> >>
> https://www.mail-archive.com/kwant-discuss@kwant-project.org/msg01497.html
> >>
> >> you claim that
> >>
> >> "the 'salt' parameter does not have any physical meaning; it's like
> >> the 'seed' that you typically specify to a random number generator."
> >>
> >> Then does it mean that the physical numbers must not to change with
> >> the set value for salt ?
> >>
> >> Last question: the string
> >>
> >> mub = 3
> >> systb = kitaev(L,t,mub,Delta,W,salt)
> >> systb = systb.finalized()
> >> hamatb = systb.hamiltonian_submatrix(sparse = False)
> >> evalsb, evecsb = la.eigh(hamatb)
> >>
> >> creates the Kitaev code with just one specific configuration for
> >> the random onsite offset, right ?
> >>
> >> Thank you very much again and best
> >>
> >> L.
> >
> >
> >
> > --
> > Abbout Adel
>
--
Abbout Adel
