Institut des
NanoSciences de Paris

Many-body systems

Composite bosons model systems like excitons in semiconductor heterostructures are also investigated. After the demonstration of Bose-Einstein condensation with indirect excitons in our group, the different quantum phases of collective states in two dimensions are explored through the Berezinskii-Kosterlitz-Thouless transition. These experiments are closely related to theoretical developments using a new many-body formalism for composite bosons and its Shiva diagrammatic representation. This formalism can be extended to different fields and a natural application is to cold quantum gazes in which the particles’ composite nature has been neglected till now.