Hi,
For time dependent site dependent hopping you just need parameters as: t1[Time] = “0.1,0.15,0.2,..." t2[Time] = “0.5,0.45,0.4,..." …
An example of time dependent Hamiltonian parameters is in the tutorial mps-05-bhquench. For example, note that you additionally need to define COMPLEX=1 (to use complex numbers= and update_each=1 (to force the Hamiltonian to be generated at each time step.
Best regards, Michele
-- ETH Zurich Michele Dolfi Institute for Theoretical Physics HIT G 32.4 Wolfgang-Pauli-Str. 27 8093 Zurich Switzerland
dolfim@phys.ethz.ch www.itp.phys.ethz.ch
+41 44 633 78 56 phone +41 44 633 11 15 fax
On 01 Jun 2014, at 14:16, bondnina bondnina@gmail.com wrote:
Dear Michele. Thank you for your very detailed answer. I have one more question. I am afraid that the approaches you have listed in your male have only static nature. Maybe I am wrong but I didn't get how to apply t parameter depending on time. That maybe useful to simulate chain dynamics for example. Best, Nina
Message: 3 Date: Wed, 28 May 2014 09:16:46 -0400 From: Michele Dolfi dolfim@phys.ethz.ch To: comp-phys-alps-users@lists.phys.ethz.ch Subject: Re: [ALPS-users] Variational hopping parameter Message-ID: C16EA761-87AF-4E04-B966-4F861E887659@phys.ethz.ch Content-Type: text/plain; charset="windows-1252"
Dear Nina,
In the latest release of ALPS 2.2.0b3 we introduced a new set of codes based on MPS. These codes use the ALPS model and lattice library, therefore there is not no problem running this kind of simulations.
To do so:
- you need to create a custom lattice with a different type for each bond.
https://alps.comp-phys.org/mediawiki/index.php/Tutorials:LatticeHOWTO
the model ?fermion Hubbard? is already able to handle different hopping amplitudes, just specify all values with the parameters t0=?, t1=?, ? where the number correspond to the bond type you specified in the lattice
finally you can setup a simulation using the new mps_evolve code. the easiest is to look at the mps-05 and mps-06 tutorials to have an idea on how to run the code.
Best regards, Michele
-- ETH Zurich Michele Dolfi Institute for Theoretical Physics HIT G 32.4 Wolfgang-Pauli-Str. 27 8093 Zurich Switzerland
dolfim@phys.ethz.ch www.itp.phys.ethz.ch
+41 44 633 78 56 phone +41 44 633 11 15 fax
On 27 May 2014, at 18:30, Michael Wall mwall.physics@gmail.com wrote:
Dear Nina,
The TEBD code in ALPS is not set up for site-dependent Hubbard parameters. Some of the other ALPS developers may be able to answer better whether such functionality will be added in near-term ALPS MPS codes. If not, Open Source MPS can perform the sorts of calculations you want to do, and eventually will become part of ALPS.
-Michael
On Fri, May 23, 2014 at 2:02 AM, bondnina bondnina@gmail.com wrote: Hi dear Alps users. I wonder is there any possibility to setup different hopping parameters for each site in the Hubbard chain and evaluate such a system using TEBD technic. Thank you for help.
-- Yours sincerely, Nina Bondarenko 1024R/EAC56154 9F6C DDF8 6873 5D19 FF9A 600E 46A4 42BE EAC5 6154
-- Yours sincerely, Nina Bondarenko 1024R/EAC56154 9F6C DDF8 6873 5D19 FF9A 600E 46A4 42BE EAC5 6154