Funding for this research was provided by:
National Centre of Competence in Research SwissMAP - The Mathematics of Physics (CH)
Swiss National Science Foundation (200021_165698)
H2020 European Research Council (CoG UniCoSM, grant agreement n.724939)
Gruppo Nazionale per la Fisica Matematica
Article History
Received: 18 September 2017
Accepted: 1 May 2018
First Online: 20 July 2018