The investigation of electron correlations in solids is one of the major research areas in modern solid state theory. Perturbative methods cannot be applied in the limit of strong electron interactions, while exact solutions have to rely on enormous computer efforts and are restricted to small system sizes. Alternatively one can approach the problem using variational wave-functions, which are not exact but may contain the essential physics of the system. For models containing strong local interactions, the most popular variational Ansatz dates back to the pioneering work of Gutzwiller in 1963-1965, who proposed a projector which reduces the weight of double occupied sites for a given Hartree-Fock state.
Since this first work, the so-called “Gutzwiller” method has been widely used for different Hamiltonians (Hubbard, Anderson) and was equally applied to study the Mott transition as well as the properties of Helium 3. Moreover the Gutzwiller approach shows strong connections with the Landau theory of Fermi liquids and with the reformulation of strongly correlated electron models in terms of slave bosons. In the past decade, numerous works lead to a renewal of interest in this method. In particular it has been successfully combined with ab-initio methods, and due to the challenge of high-Tc superconductors it has also been extended towards projected BCS states. Therefore, in future, the Gutzwiller method will remain an important theoretical approach for the investigation and understanding of electronic correlations in solids. The workshop provides the opportunity of bringing together scientists with experience in the whole variety of applications of the Gutzwiller method. This will allow for stimulating discussions, exchange of knowledge and the development of further progress in this field.

Due to this renewal, the original method has many extensions which are the matter of the workshop we want to organize in 2014. This workshop could be seen as a successor of a workshop to be held in Marburg, Germany in October 2005, and is intended to present most recent advances in this domain.
Topics range from method developments to applications:
• Exact evaluation in one and infinite spatial dimensions; Analytical approaches.
• Extensions to anisotropic non-local projection and numerical approaches
• Time-dependent variational wave functions.
• Coupling to ab-initio methods (Hartree-Fock or DFT).
• Slave-boson theories for Hubbard-type models
• Mott insulators and Mott transition.
• Transition metals and their compounds.
• “f”electrons systems: actinides and rare earth compounds.
• Extended hard-core boson theory for strong coupling superconductivity
• Gutzwiller wave-functions combined with superconductivity; Application to high-Tc cuprates and Gossamer superconductors.
• Local probe of electronic correlation and renormalization.
*Coupling to tight-binding approaches suitable for molecular dynamics simulations.