Report on the Topical Meeting

“Advanced First-principles Calculations and Many-body Effects in Correlated Electrons”

As a part of activities in “Strong Correlation Quantum Theory Forum” supported by “Quantum Science of Strongly Correlated Systems (QS2C)”, a topical meeting on "Advanced First-Principles Calculations and Many-body Effects in Correlated Electrons" was held on 1st – 2nd September 2010.

20 invited speakers (16 from abroad, and 4 from Japan) who are working in the field of first-principles calculation for strongly correlated electron systems or the combination of many-body and ab initio calculation were invited. Together with a talk by Dr. S. Bahramy from QS2C, there were 21 talks in total. Although the schedule was quite tight, all 30 minutes talks were followed by many open discussions among the participants, and the atmosphere of the meeting was very active.
The list of the invited speakers is as follows:

F. Aryasetiawan (Chiba)
L. Boeri (MPI, Stuttgart),
M. Capone (SISSA, Trieste)
X. Dai (CAS, Beijing)
E. Gull (Columbia Univ.)
G.Y. Guo (Taiwan Univ)
Erik Koch (Res. Center Juelich Gmbh)
T. Kotani (Tottri)
W. Ku (Brookhaven)
J. Kunes (Academy of Science of Czech, Prague)
F. Lechermann (Univ. Hamburg)
T. Miyake (AIST, Tsukuba)
S. Okamoto (Oak Ridge)
E. Pavarini (Res. Center Juelich Gmbh)
G. Sangiovanni (Vienna Univ. Tech.)
S. Savrasov (UC-Davis)
I. Solovyev (NIMS, Tsukuba)
A. Toschi (Vienna Univ. Tech.)
P. Werner (ETH Zurich)
X. Yang (Nanyang Tech. Univ., Singapore)

In the meeting, the following topics were intensively discussed.

[1] Electronic structure/properties of correlated materials Studies based on ab initio calculation for correlated materials of current interest such as iron-based superconductors, multiferroic materials, topological materials, organic superconductors were presented. New approaches/methods to go beyond the local density approximation (LDA) and even beyond the combination of LDA and the dynamical mean field theory (LDA+DMFT) were discussed.

[2] Design of functional materials / heterostructures One of the big advantages of first-principles calculation having no empirical parameter is that we can “predict” or “design” physical properties of unknown materials/systems. As an example of such attempts, studies on heterostructures realized with layers of correlated materials were presented and critically discussed.

[3] Ab initio derivation of low energy models To study correlation effects in materials quantitatively, one promising approach is combining ab initio and many-body methods for correlated models (LDA+DMFT is one typical example). In this approach, ab initio derivation of the effective model representing the low energy characteristics of each material is a crucial step. In the meeting, we had an intensive discussion on this issue, especially on how to construct the many-body terms in the effective Hamiltonian from first-principles inputs.

[4] Methodological developments in many-body methods Another important topic in the combination of first-principles and model calculations is how to solve the derived effective low-energy model accurately. While “realistic” models can generally be complicated and difficult to solve, recent developments in new techniques and their applications were presented.

In total, there were 45 participants in the meeting. Many of the invited speakers stayed RIKEN for a few weeks to exchange their ideas, to have discussions on their recent studies, and to start new joint projects. They really enjoyed their short research stay in RIKEN.


“2010 Topical Meeting of QS2C Theory Forum” will be held in September 1-2, 2010 at RIKEN, as one of the activities in “Strong Correlation Quantum Theory Forum” supported by “Quantum Science of Strongly Correlated Systems”(leader: Prof. Yoshinori Tokura, University of Tokyo and RIKEN) in “World-Leading Innovative R&D on Science and Technology (FIRST Program)”.

2010 Topical Meeting title is
"Advanced First-Principles Calculations and Many-Body Effects in Correlated Electrons".

The purpose of the meeting is to promote the communications and collaborations among the participants working on the first-principles calculations and many-body effects in correlated electrons.

More explicitly, the themes to be discussed include

  • electronic structure/properties of correlated materials
  • design of functional materials/ hetrostructures
  • methodological developments in many-body methods
  • ab inito derivation of low energy models

To stimulate intensive discussions, the number of participants will be limited to approximately 50 people, including 23 invited speakers, and many of invited speakers will stay RIKEN several weeks before and/or after the meeting.