%0 Journal Article %T Interferometry with large molecules: exploration of coherence, decoherence and novel beam methods %A Arndt %A Markus %A Hackerm¨šller %A Lucia %A Reiger %A Elisabeth %J Brazilian Journal of Physics %D 2005 %I Scientific Electronic Library Online %R 10.1590/S0103-97332005000200004 %X quantum experiments with complex objects are of fundamental interest as they allow to quantitatively trace the quantum-to-classical transition under the influence of various interactions between the quantum object and its environment. we briefly review the present status of matter wave interferometry and decoherence studies with large molecules and focus in particular on the challenges for novel beam methods for molecular quantum optics with clusters, macromolecules or nanocrystals. %U http://www.scielo.br/scielo.php?script=sci_abstract&pid=S0103-97332005000200004&lng=en&nrm=iso&tlng=en