Energy Gap - Comp-phys-alps-users

10 Apr 2009

Send Comp-phys-alps-users mailing list submissions to
       comp-phys-alps-users@phys.ethz.ch
<mailto:comp-phys-alps-users@phys.ethz.ch>

To subscribe or unsubscribe via the World Wide Web, visit

 https://webmail.phys.ethz.ch/mailman/listinfo/comp-phys-alps-users
or, via email, send a message with subject or body 'help' to
       comp-phys-alps-users-request@phys.ethz.ch
<mailto:comp-phys-alps-users-request@phys.ethz.ch>

You can reach the person managing the list at
       comp-phys-alps-users-owner@phys.ethz.ch
<mailto:comp-phys-alps-users-owner@phys.ethz.ch>

When replying, please edit your Subject line so it is more specific
than "Re: Contents of Comp-phys-alps-users digest..."

Today's Topics:

  1. dynamical correlation functions (jessica.alfonsi@unipd.it
<mailto:jessica.alfonsi@unipd.it>)
  2. Energy Gap (zhian asadzadeh)
  3. Re: Energy Gap (Adrian E. Feiguin)
  4. uniform magnetic susceptibility (Guilin Zhuang)

----------------------------------------------------------------------

Message: 1
Date: Mon, 23 Mar 2009 12:48:14 +0100 (CET)
From: jessica.alfonsi@unipd.it <mailto:jessica.alfonsi@unipd.it>
Subject: [ALPS-users] dynamical correlation functions
To: comp-phys-alps-users@phys.ethz.ch
<mailto:comp-phys-alps-users@phys.ethz.ch>
Message-ID:
       <25a2823199cb7c2f2d21169a68d1a5b0.squirrel@webmail.unipd.it
<mailto:25a2823199cb7c2f2d21169a68d1a5b0.squirrel@webmail.unipd.it>>
Content-Type: text/plain;charset=iso-8859-1

Hello everybody,
I'm interested in starting using ALPS project, in particular for
computing
optical spectral functions starting from exact diagonalization and
dynamical correlation function for optical conductivity. However,
I read
in papers about ALPS 1.3 release that these will be implemented in
release
1.4 . When do you plan to release at least the first beta of ALPS
1.4 ? Is
it possible to use a patched SVN version ?

Thank you and best wishes

Jessica Alfonsi

------------------------------

Message: 2
Date: Tue, 24 Mar 2009 09:57:55 +0330
From: zhian asadzadeh <zhian.asadzadeh@gmail.com
<mailto:zhian.asadzadeh@gmail.com>>
Subject: [ALPS-users] Energy Gap
To: comp-phys-alps-users@phys.ethz.ch
<mailto:comp-phys-alps-users@phys.ethz.ch>
Message-ID:

 <89e5d6760903232327p5fe2f942x8fde9c344cceb0d2@mail.gmail.com
<mailto:89e5d6760903232327p5fe2f942x8fde9c344cceb0d2@mail.gmail.com>>
Content-Type: text/plain; charset="iso-8859-1"

Hi Dear,

I tried to calculate energy gap for ferrimagnetic ladder. in this
paper (
Phy Rev B, 63, 054432) it has been done which you can find in
table I. I used the periodic boundary condition because in the
case of open
boundary condition the  energy converges very slowly.
I have achieved the following result.
E0= -0.757036
E1= -0.757032

I have used the following input file: I have tried for inter chain
coupling
J' = 0.2 with the notation of this paper.

LATTICE="ferrimagnetic ladder"
SWEEPS=4
MAXSTATES=300
MODEL="spin", L=30
local_S0=1/2,local_S1=1,Jxy0=1,h=0.0,Jxy1=0.2,Jz1=0.2
BC1=periodic,BC2=periodic
NUMBER_EIGENVALUES=2
Jz0=1
{Gamma=0.0;}

which L is the number of unit cell and h, Gamma are longitudinal and
transverse magnetic field respectively. Jz0 , Jxy0 are chain
couplings and
Jz1, and Jxy1 are inter chain couplings.
we see that the result is not concur with this paper for energy gap.
I see in this paper lanczos method is used but I expect that the
result be
same in 4 digit.
please let me know what is wrong?

Thanks,
Mohammad.

On Wed, Mar 18, 2009 at 2:30 PM,
<comp-phys-alps-users-request@phys.ethz.ch
<mailto:comp-phys-alps-users-request@phys.ethz.ch>>wrote:

> Send Comp-phys-alps-users mailing list submissions to
>        comp-phys-alps-users@phys.ethz.ch
<mailto:comp-phys-alps-users@phys.ethz.ch>
>
> To subscribe or unsubscribe via the World Wide Web, visit
>      
 https://webmail.phys.ethz.ch/mailman/listinfo/comp-phys-alps-users
> or, via email, send a message with subject or body 'help' to
>        comp-phys-alps-users-request@phys.ethz.ch
<mailto:comp-phys-alps-users-request@phys.ethz.ch>
>
> You can reach the person managing the list at
>        comp-phys-alps-users-owner@phys.ethz.ch
<mailto:comp-phys-alps-users-owner@phys.ethz.ch>
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Comp-phys-alps-users digest..."
>
>
> Today's Topics:
>
>   1. Energy Gap (zhian asadzadeh)
>   2. Re: Energy Gap (Matthias Troyer)
>
>
>
----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 17 Mar 2009 14:43:46 +0330
> From: zhian asadzadeh <zhian.asadzadeh@gmail.com
<mailto:zhian.asadzadeh@gmail.com>>
> Subject: [ALPS-users] Energy Gap
> To: comp-phys-alps-users@phys.ethz.ch
<mailto:comp-phys-alps-users@phys.ethz.ch>
> Message-ID:
>      
 <89e5d6760903170413w7e72ef85i873b8d47564f4320@mail.gmail.com
<mailto:89e5d6760903170413w7e72ef85i873b8d47564f4320@mail.gmail.com>>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi Dear,
>
> Thank you for your consideration.
> My model is anisotropic Ferrimagnetic chain in transverse
magnetic field.
> when I say the result is wrong I mean when I have tried to
obtain energy
> gap
> for some problems and models which have been solved earlier I
saw  the
> result doesn't agree with those earlier results. for example
spin one and
> half-one chain and ferrimagnetic chain and  anisotropic
ferrimagnetic
> ladder.
> Something is not very obvius for me, how DMRG calculate ground
state and
> first exited state from one wave function ?!
>
> Thanks,
> Zhian.
>
>
> On Tue, Mar 17, 2009 at 2:30 PM,
> <comp-phys-alps-users-request@phys.ethz.ch
<mailto:comp-phys-alps-users-request@phys.ethz.ch>>wrote:
>
> > Send Comp-phys-alps-users mailing list submissions to
> >        comp-phys-alps-users@phys.ethz.ch
<mailto:comp-phys-alps-users@phys.ethz.ch>
> >
> > To subscribe or unsubscribe via the World Wide Web, visit
> >
> https://webmail.phys.ethz.ch/mailman/listinfo/comp-phys-alps-users
> > or, via email, send a message with subject or body 'help' to
> >        comp-phys-alps-users-request@phys.ethz.ch
<mailto:comp-phys-alps-users-request@phys.ethz.ch>
> >
> > You can reach the person managing the list at
> >        comp-phys-alps-users-owner@phys.ethz.ch
<mailto:comp-phys-alps-users-owner@phys.ethz.ch>
> >
> > When replying, please edit your Subject line so it is more
specific
> > than "Re: Contents of Comp-phys-alps-users digest..."
> >
> >
> > Today's Topics:
> >
> >   1. Re: Energy Gap (Matthias Troyer)
> >
> >
> >
----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Mon, 16 Mar 2009 12:33:11 -0700
> > From: Matthias Troyer <troyer@phys.ethz.ch
<mailto:troyer@phys.ethz.ch>>
> > Subject: Re: [ALPS-users] Energy Gap
> > To: comp-phys-alps-users@phys.ethz.ch
<mailto:comp-phys-alps-users@phys.ethz.ch>
> > Message-ID: <43E825E5-7BE3-4EA0-9C2A-20A1FC8C21AF@phys.ethz.ch
<mailto:43E825E5-7BE3-4EA0-9C2A-20A1FC8C21AF@phys.ethz.ch>>
> > Content-Type: text/plain; charset=US-ASCII; format=flowed;
delsp=yes
> >
> >
> > On Mar 16, 2009, at 2:01 AM, zhian asadzadeh wrote:
> >
> > > Hi All,
> > >
> > > I want to calculate energy gap for spin chain with DMRG. I set
> > > NUM_EIGENVALUES=2 in my parm file but the result which
 achieved is
> > > wrong.
> > > Is it necessary to determine something else for example the
sector
> > > which DMRG work in it? in my problem I dont have any good
symmetry
> > > and I can not easily determine the sector which the first exited
> > > state is in it. I would be very appreciate if someone could
please
> > > help me.
> > >
> > > Thanks,
> > > Zhian.
> >
> > Can you please send more details about your model, or better
yet the
> > input file? An what do you mean exactly by saying that the
result is
> > wrong?
> >
> > Matthias
> >
> >
> >
> > End of Comp-phys-alps-users Digest, Vol 36, Issue 10
> > ****************************************************
> >
> 