Hi Emanuel Gull,

I need to run DMFT for multi-orbitals with density-density interaction in the weak-coupling limit(from U/W=0.3 to U/W=1.0). In this limit I am thinking that weak coupling solver(Interaction expansion) is more efficient than Strong coupling. That why I am looking for Interaction expansion. Is it right?

The procedure for setting up the parameter file with multi-orbitals for Interaction expansion is it similar to Hybridization expansion( As you mentioned in Hybridization Document in the Alps Nightly version).

How can I set up parameter file? Can I follow the Documentation in the alps page or am I need to look in to the source code?

Thanks, Dasari.

----- Original Message ----- From: "Emanuel Gull" emanuel.gull@gmail.com To: comp-phys-alps-users@lists.phys.ethz.ch Sent: Sunday, March 10, 2013 11:44:57 PM Subject: Re: [ALPS-users] DMFT: Interaction expansion in the multi-orbitals with density-density interactions

Hi Dasari,

Recently I installed alps-2.1.1-r6176-src on my Desktop. For my purpose I need to use multi-orbital weak coupling ctqmc as an impurity solver with in DMFT.

In the alps is it possible to run the dmft with interaction expansion as an impurity solver for multi-orbitals with density-density interactions?

yes, there is a general multi-orbital density-density interaction expansion solver included in ALPS. For this type of interaction the hybridization expansion is typically more efficient. Are you sure that you need the interaction expansion?

The class

MultiBandDensityHubbardInteractionExpansion

implements your density-density interaction expansion, have a look at model.cpp.

If possible can I use it for the finite dimensional lattices(2D or 3D)?

Yes, you can use it for any general density of states.

I have seen examples in the tutorial for multi-orbitals with hybridization solver only.

The reason is the one above: Generally, the hybridization expansion is much more efficient.

Best, Emanuel