TRR 49:  Condensed Matter Systems with Variable Many-Body Interactions

• Subject Area: Physics ; Chemistry
• Term: from 2007 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 31867626

The understanding of the collective behaviour of large assemblies of interacting quantum objects represents one of the central themes in contemporary physical research. Phenomena such as novel types of superconductivity or interaction-induced insulating states and their relation to other kinds of orders associated with spin-, charge-, orbital- or lattice degrees of freedom continue to pose major challenges to modern physics.The concept of the SFB/TR 49 is to investigate selected phenomena of interacting many-body systems in a broader, less material-specific context under well-controllable conditions. The phenomena to be studied include the Mott metal-insulator transition and the nearby anomalous phases including superconductivity, charge-ordered- or multiferroic insulating states, non-magnetic spin-liquids as well as Bose-Einstein condensates under diverse conditions.These collective states will be explored by using a wide spectrum of materials, ranging from simple model systems such as ultracold atoms and ions or magnon gases to complex quantum magnets and metal-organic solids. All systems have in common a high degree of variability, enabling a systematic materials design to be performed through varying the systems¿ chemical and/or physical parameters.While in the second funding period dynamical properties and the effects of geometric frustration and inhomogeneities have been studied, aspects related to the coupling of the correlated system to lattice degrees of freedom will come to the fore in the third funding period.The SFB/TR 49 benefits from a strong interaction between theory and experiment both in the area of physics and chemistry, and combines the fields of quantum optics and solid state research, which hitherto have had only little overlap. Through its Integrated College for the Advancement of Postgraduate Education, the SFB/TR 49 provides best conditions for the training and promotion of young researchers.

• DFG Programme: CRC/Transregios

Completed projects

• A01 - Ultrakalte Fermi-Mischungen in optischen Gittern (Project Head Bloch, Immanuel )
• A02 - Räumlich adressierbare Quantengase (Project Heads Bloch, Immanuel ;  Kuhr, Stefan )
• A03 - Inhomogeneous quantum phases and dynamics in ultracold gases and hybrid atom-ion systems (Project Head Hofstetter, Walter )
• A05 - Advanced numerical methods for correlated quantum gases (Project Heads Eggert, Sebastian ;  Fleischhauer, Michael )
• A06 - Multiflavour Mott transitions and magnetism of ultracold quantum gases on optical lattices (Project Head Blümer, Nils Michael )
• A07 - Collective effects and instabilities of a magnon gas (Project Heads Hillebrands, Burkard ;  Serha, Oleksandr )
• A08 - Interacting magnons and critical behaviour of bosons (Project Head Kopietz, Peter )
• A09 - Ultracold Bose gases with variable interactions (Project Head Ott, Herwig )
• A10 - Designing spin-spin interactions in cold ion crystals (Project Heads Gerritsma, Rene ;  Schmidt-Kaler, Ferdinand )
• A11 - Thermodynamics and dynamics of onedimensional quantum systems (Project Head Sirker, Jesko )
• A12 - Multi-polaron effects with spinless and spinful impurities in a bosonic quantum gas (Project Head Widera, Artur )
• B01 - Interacting magnetic excitations in quantum spin systems - Thermodynamic investigations (Project Heads Lang, Michael ;  Wolf, Bernd )
• B02 - Ab initio modelling and design of correlated materials (Project Heads Jeschke, Harald ;  Valenti, Maria Roser )
• B03 - Correlations in antiferromagnets (Project Head Eggert, Sebastian )
• B04 - Single crystal growth of tunable quantum spin systems (Project Heads Aßmus, Wolf ;  Krellner, Cornelius ;  Ritter, Franz )
• B05 - Rational design with input from DFT calculations and preparation of coordination polymer-based quantum magnets (Project Heads Baumgarten, Martin ;  Wagner, Matthias )
• B06 - Collective phenomena in organic charge-transfer salts close to the Mott transition (Project Heads Lang, Michael ;  de Souza, Mariano )
• B07 - Renormalized meanfield theory and variational Monte-Carlo studies for organic superconductors (Project Head Gros, Claudius )
• B08 - High-resolution photoelektron momentum microscopy of organic charge-transfer salts at variable temperature (Project Heads Aeschlimann, Martin ;  Schönhense, Gerd )
• B09 - Thin film investigations on ferroelectric organic charge transfer systems (Project Head Huth, Michael )
• B10 - Design, synthesis, physical and theoretical characterization of new charge-transfer complexes (Project Heads Baumgarten, Martin ;  Müllen, Klaus )
• B11 - Low-frequency electron dynamics of organic charge-transfer salts studied by fluctuation spectroscopy (Project Head Müller, Jens )
• B12 - Investigation of electron correlation effects in organic charge-transfer salts using scanning tunneling spectroscopy (Project Head Elmers, Hans-Joachim )
• B13 - Investigation of spin systems via ab initio quantum Monte Carlo and perturbation theory (Project Heads Foyevtsova, Kateryna ;  Valenti, Maria Roser )
• MGK - College for the advancement of postgraduate education (Project Head Eggert, Sebastian )
• Z - Centrals tasks (Project Head Lang, Michael )

• Applicant Institution: Goethe-Universität Frankfurt am Main
• Co-Applicant Institution: Johannes Gutenberg-Universität Mainz; Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau
• Participating Institution: Max-Planck-Institut für Polymerforschung
• Spokesperson: Professor Dr. Michael Lang