Alladi Ramakrishnan Hall

Quantum localisation in chaotic systems

M S Santhanam

Indian Institute of Science Education and Research (IISER), Pune

Localisation is one of the unexpected features that emerges when chaotic Hamitonian systems are quantized. This manifests itself in two different forms, both forms originating due to destructive quantum interferences. In time-independent systems, localisation appears as 'scarred' states and is influenced by the unstable classical periodic orbits. On the other hand, in a class of time dependent chaotic systems it is analogous to Anderson localisation in condensed matter physics. Both these localisation effects have been experimentally observed. In this talk, major developments in this area in the last three decades will be surveyed. In the second part of the talk, some of our recent work relating quantum localisation to non-KAM chaos and decoherence effects will be discussed.