Comp-phys-alps-users

comp-phys-alps-users@lists.phys.ethz.ch

1244 discussions

Correlation measurment
by zhian asadzadeh 05 Mar '09

05 Mar '09

Hi All, I am going to measure <SxSx>, <SySy> two point correlations with DMRG . Please let me know what i must do or add in the lattice and model files? Thanks, Mohammad.

1 0

current correlation function with fulldiag and sparsediag
by khalid hassan 02 Mar '09

02 Mar '09

my question about current correlation function with fulldiag and sparsediag remains unanswered --- On Fri, 2/27/09, comp-phys-alps-users-request(a)phys.ethz.ch <comp-phys-alps-users-request(a)phys.ethz.ch> wrote: > From: comp-phys-alps-users-request(a)phys.ethz.ch <comp-phys-alps-users-request(a)phys.ethz.ch> > Subject: Comp-phys-alps-users Digest, Vol 35, Issue 8 > To: comp-phys-alps-users(a)phys.ethz.ch > Date: Friday, February 27, 2009, 4:00 PM > Send Comp-phys-alps-users mailing > list submissions to > comp-phys-alps-users(a)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(a)phys.ethz.ch > > You can reach the person managing the list at > comp-phys-alps-users-owner(a)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. current correlation function for > fermionic hubbard model > (khalid hassan) > 2. Re: current correlation function for > fermionic hubbard model > (Adrian E. Feiguin) > 3. current correlation function for > fermionic hubbard model > using alps (khalid hassan) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 26 Feb 2009 13:25:11 -0800 (PST) > From: khalid hassan <mkhloane(a)yahoo.com> > Subject: [ALPS-users] current correlation function for > fermionic > hubbard model > To: comp-phys-alps-users(a)phys.ethz.ch > Message-ID: <826945.64034.qm(a)web59410.mail.ac4.yahoo.com> > Content-Type: text/plain; charset=us-ascii > > > Can alps can calculate the current correlation function for > the fermionic hubbard model model for say two site. I have > been using alps to calculate cahrge coorelation function > > the charge correlation function is > > < n_i n_j > = < c_i^+ c_i c_i^+ c_i > > > where as the current correlation function is > > < j_i j_j > = < c_i^+ c_j c_k^+ c_l > > > see the changing indexes. > > If it is possible then send me the program statement > > Best regards > > Khalid Loane > > > > > > > > > ------------------------------ > > Message: 2 > Date: Thu, 26 Feb 2009 14:19:05 -0800 > From: "Adrian E. Feiguin" <afeiguin(a)kitp.ucsb.edu> > Subject: Re: [ALPS-users] current correlation function for > fermionic > hubbard model > To: comp-phys-alps-users(a)phys.ethz.ch > Message-ID: <49A71559.80403(a)kitp.ucsb.edu> > Content-Type: text/plain; charset=ISO-8859-1; > format=flowed > > Hi Khalid, > > Are you using exact diagonalization, or DMRG? > > At the present, it hasn't been implemented in the DMRG > code. > > Saludos, > <ADRIAN> > > khalid hassan wrote: > > >Can alps can calculate the current correlation function > for the fermionic hubbard model model for say two site. I > have been using alps to calculate cahrge coorelation > function > > > >the charge correlation function is > > > >< n_i n_j > = < c_i^+ c_i c_i^+ c_i > > > > > >where as the current correlation function is > > > >< j_i j_j > = < c_i^+ c_j c_k^+ c_l > > > > > >see the changing indexes. > > > >If it is possible then send me the program statement > > > >Best regards > > > >Khalid Loane > > > > > > > > > > > > > > > > > > > > > > ------------------------------ > > Message: 3 > Date: Fri, 27 Feb 2009 01:28:00 -0800 (PST) > From: khalid hassan <mkhloane(a)yahoo.com> > Subject: [ALPS-users] current correlation function for > fermionic > hubbard model using > alps > To: comp-phys-alps-users(a)phys.ethz.ch > Message-ID: <976367.6290.qm(a)web59408.mail.ac4.yahoo.com> > Content-Type: text/plain; charset=us-ascii > > > > > I am using alps for the calculation of charge correlation > function for the fermionic hubbard model. Now I want to > calculate the current correlation function. > > the expression for the charge correlation function is > > < n_i : n_j > = < c_i^+ c_i > : c_j^+ c_j > > > the expression for the current correlation function is > > < j_i : j_j > = < c_i^+ c_j > : c_k^+ c_l > > > Notice the changing indices in the current expression. > > If it is possible then please give the program statements > doing this > > Best Regards > > Khalid Loane > > > > > > > End of Comp-phys-alps-users Digest, Vol 35, Issue 8 > *************************************************** >

1 0

Operator difinition
by zhian asadzadeh 02 Mar '09

02 Mar '09

Hi Dear, > > Thank you very much for your consideration. yes my model mixes states > with different Sz. > let me know DMRG works with complex vectors or not? and Can I change > the basis which DMRG works in it? > > Thanks a lot > Mohammad. On Mon, Mar 2, 2009 at 2:30 PM, <comp-phys-alps-users-request(a)phys.ethz.ch>wrote: > Send Comp-phys-alps-users mailing list submissions to > comp-phys-alps-users(a)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(a)phys.ethz.ch > > You can reach the person managing the list at > comp-phys-alps-users-owner(a)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. Operator difinition (zhian asadzadeh) > 2. Re: Operator difinition (Adrian E. Feiguin) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 1 Mar 2009 15:37:58 +0330 > From: zhian asadzadeh <zhian.asadzadeh(a)gmail.com> > Subject: [ALPS-users] Operator difinition > To: comp-phys-alps-users(a)phys.ethz.ch > Message-ID: > <89e5d6760903010407m44b1729raa91afa47e962e18(a)mail.gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > Hi Dear, > > Thank you very much for your consideration. yes my model mixes states with > different Sz. > let me know DMRG works with complex vectors or not? and Can I change the > basis which DMRG works in it? > > Thanks a lot > Mohammad. > > On Sun, Mar 1, 2009 at 2:30 PM, > <comp-phys-alps-users-request(a)phys.ethz.ch>wrote: > > > Send Comp-phys-alps-users mailing list submissions to > > comp-phys-alps-users(a)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(a)phys.ethz.ch > > > > You can reach the person managing the list at > > comp-phys-alps-users-owner(a)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. Operator definition (zhian asadzadeh) > > 2. Re: Operator definition (Adrian E. Feiguin) > > > > > > ---------------------------------------------------------------------- > > > > Message: 1 > > Date: Sat, 28 Feb 2009 15:11:34 +0330 > > From: zhian asadzadeh <zhian.asadzadeh(a)gmail.com> > > Subject: [ALPS-users] Operator definition > > To: comp-phys-alps-users(a)phys.ethz.ch > > Message-ID: > > <89e5d6760902280341r7ca16b5fm506e562c4f043c64(a)mail.gmail.com> > > Content-Type: text/plain; charset="iso-8859-1" > > > > Hi All, > > > > I am using DMRG for my problem, I need to calculate expectation value of > Y > > component of Spin operator (Sy) , As a result, I need to define it in the > > model.xml file. How I can define it? I tried with > > Sy(i)=1/(2*sqrt(-1))*(Splus(i)-Sminus(i)), but I got incorrect results. > I > > will be very appreciate if someone could help me? > > > > Thank you very much, > > Mohammad. > >

1 0

Operator difinition
by zhian asadzadeh 01 Mar '09

01 Mar '09

Hi Dear, Thank you very much for your consideration. yes my model mixes states with different Sz. let me know DMRG works with complex vectors or not? and Can I change the basis which DMRG works in it? Thanks a lot Mohammad. On Sun, Mar 1, 2009 at 2:30 PM, <comp-phys-alps-users-request(a)phys.ethz.ch>wrote: > Send Comp-phys-alps-users mailing list submissions to > comp-phys-alps-users(a)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(a)phys.ethz.ch > > You can reach the person managing the list at > comp-phys-alps-users-owner(a)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. Operator definition (zhian asadzadeh) > 2. Re: Operator definition (Adrian E. Feiguin) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 28 Feb 2009 15:11:34 +0330 > From: zhian asadzadeh <zhian.asadzadeh(a)gmail.com> > Subject: [ALPS-users] Operator definition > To: comp-phys-alps-users(a)phys.ethz.ch > Message-ID: > <89e5d6760902280341r7ca16b5fm506e562c4f043c64(a)mail.gmail.com> > Content-Type: text/plain; charset="iso-8859-1" > > Hi All, > > I am using DMRG for my problem, I need to calculate expectation value of Y > component of Spin operator (Sy) , As a result, I need to define it in the > model.xml file. How I can define it? I tried with > Sy(i)=1/(2*sqrt(-1))*(Splus(i)-Sminus(i)), but I got incorrect results. I > will be very appreciate if someone could help me? > > Thank you very much, > Mohammad. >

2 1

Operator definition
by zhian asadzadeh 28 Feb '09

28 Feb '09

Hi All, I am using DMRG for my problem, I need to calculate expectation value of Y component of Spin operator (Sy) , As a result, I need to define it in the model.xml file. How I can define it? I tried with Sy(i)=1/(2*sqrt(-1))*(Splus(i)-Sminus(i)), but I got incorrect results. I will be very appreciate if someone could help me? Thank you very much, Mohammad.

2 1

I am using it with exact diagonalization
by khalid hassan 27 Feb '09

27 Feb '09

I am using it with exact diagonalization. If it is implemented for the exact diagonalization please give the program statement. > > Message: 2 > Date: Thu, 26 Feb 2009 14:19:05 -0800 > From: "Adrian E. Feiguin" <afeiguin(a)kitp.ucsb.edu> > Subject: Re: [ALPS-users] current correlation function for > fermionic > hubbard model > To: comp-phys-alps-users(a)phys.ethz.ch > Message-ID: <49A71559.80403(a)kitp.ucsb.edu> > Content-Type: text/plain; charset=ISO-8859-1; > format=flowed > > Hi Khalid, > > Are you using exact diagonalization, or DMRG? > > At the present, it hasn't been implemented in the DMRG > code. > > Saludos, > <ADRIAN> > > khalid hassan wrote: > > >Can alps can calculate the current correlation function > for the fermionic hubbard model model for say two site. I > have been using alps to calculate cahrge coorelation > function > > > >the charge correlation function is > > > >< n_i n_j > = < c_i^+ c_i c_i^+ c_i > > > > > >where as the current correlation function is > > > >< j_i j_j > = < c_i^+ c_j c_k^+ c_l > > > > > >see the changing indexes. > > > >If it is possible then send me the program statement > > > >Best regards > > > >Khalid Loane > > > >

1 0

current correlation function for fermionic hubbard model using alps
by khalid hassan 27 Feb '09

27 Feb '09

I am using alps for the calculation of charge correlation function for the fermionic hubbard model. Now I want to calculate the current correlation function. the expression for the charge correlation function is < n_i : n_j > = < c_i^+ c_i : c_j^+ c_j > the expression for the current correlation function is < j_i : j_j > = < c_i^+ c_j : c_k^+ c_l > Notice the changing indices in the current expression. If it is possible then please give the program statements doing this Best Regards Khalid Loane

1 0

Simple graphs and complex hopping parameter(t)
by Akinlolu Akande 09 Feb '09

09 Feb '09

Hi all, Is it not possible to define a simple graph with complex hopping parameter in the Hamiltonian when using fulldiagonization? For example, a 4-site chain is defined using a simple graph as <LATTICES> <GRAPH name="Chain" vertices=" 4"> <VERTEX id=" 1" type="0"></VERTEX> <VERTEX id=" 2" type="0"></VERTEX> <VERTEX id=" 3" type="0"></VERTEX> <VERTEX id=" 4" type="0"></VERTEX> <EDGE type="0" source=" 1" target=" 2"/> <EDGE type="0" source=" 2" target=" 3"/> <EDGE type="0" source=" 3" target=" 4"/> </GRAPH> </LATTICES> which I could also use the lattices.xml in the lattice libraries.I discovered that when the lattice in the libraries is used, it works well for complex hopping but using a simple graphs I got the following errors 'can not convert complex number into real one'.Any reason for this error?The reason I want to use a simple graph is because I want to use a different lattice structure for my calculations. Thanks Akin

5 10

definition of energy density/heat capacity
by Fritz Koermann 08 Feb '09

08 Feb '09

Hi alps community, does the "Energy Density" output in the classical spinmc correspond to the (Total Energy)/spins and the analogue "Energy Density in the quantum case, e.g. using loop, to (Total Energy)/volume? Since for simple cubic systems both energy densities are equal but for a simple bcc lattice they differ by a factor of 2 so I wonder if they are differently defined? If so, does the same apply consistently to the calculated heat capacities (are they calculated using the fluctuations of the corresponding energy densities)? Best, Fritz --- Max-Planck-Institut für Eisenforschung GmbH Max-Planck-Straße 1 D-40237 Düsseldorf Handelsregister B 2533 Amtsgericht Düsseldorf Geschäftsführung Prof. Dr. Jörg Neugebauer Prof. Dr. Dierk Raabe Prof. Dr. Martin Stratmann Dipl.-Kfm. Herbert Wilk Ust.-Id.-Nr.: DE 11 93 58 514 Steuernummer: 105 5891 1000 -------------------------------------------------

2 1

Measurements
by Jakub Zakrzewski 04 Feb '09

04 Feb '09

Hello All, coould someone more experienced than me could explain briefly what type of measurements (averages of observables) may be extracted from current version. I am most interested in boson model now but question is more general. The section on parameters/measurements is unfortunately missing in wiki... Example: MEASURE_LOCAL[Local density]=n allows to get occupation of sites <n_i> for Bose-Hubbard. (Thanks, Akin, for this example). Probably other averages can be extracted but how? I tired a second moment by typing simply MEASURE_LOCAL[Local density^2]=n2 that for sparse/full diagonalization gives (e.g. sparse) Cannot evaluate expression n2(i) similarly for MEASURE_LOCAL[Compressibility]=kappa [actually in one of the files kappa(i) seems to be evaluated as it should from n2(i) and n(i) ] Worm algorithm in QMC yields: Will not measure "Compressibility" since it is off-diagonal or not a site operator Will not measure "Local density^2" since it is off-diagonal or not a site operator (which are apparently incorrect comments anyway) anybody kind enough to help? Best wishes kuba

1 0

Jump to page:

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

Comp-phys-alps-users