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Emil Johansson BergholtzProfessor

Om mig

I'm a theoretical physicsist who is faschinated by the world of quantum mechanics, in particular the by collective behaviour of many particles under extreme conditions, their exuberant phenomenology and possible impact on future technology. 

With the help of the Wallenberg Academy Fellows program, I returned to my alma mater Stockholm University in 2016 after eight years abroad -- as a Distinguished PKS fellow at the Max Planck Institute for the Physics of Complex Systems in Dresden and as an Emmy Noether Group Leader at the Free University of Berlin.


I teach courses on several topics, the last few years on Advanced Quantum Mechanics, and in the coming academic year (2020/2021) I will mainly lead more specialized research seminars. 


We work broadly in theoretical physics with an emphasis on collective quantum mechanical phenomena that occur in systems with a macroscopic number of particles. Most saliently, we study quantum many-particle systems for which topology, entanglement and interactions play important roles. These include fractional quantum Hall states, geometrically frustrated magnets, non-equilibrium systems, Weyl semimetals and various instances of flat band models. A common feature in these systems is that their low-energy quasiparticles bear little or no resemblance to their electronic constituents. Instead, the quasiparticles have intriguing properties such as fractional charge and statistics. To understand these notoriously complex systems we use a combinationof analytical and numerical methods, beyond standard many-body theory, including exact diagnalization, field theory, strong coupling expansions etc., we occasionally adopt new methods and concepts from quantum information theory, including entanglement quantifiers and tensor networks, and contemporary mathematics, such as compressed sensing.

Our research brings together several frontiers of basic science, while at the same time having the potential to provide the basis of future technological advances such as robust “topological quantum computers”

My research group presently (Fall 2020) consists of Elisabet Edvardsson (PhD student), Marcus Stålhammar (PhD student), Ahmed Abouelkomsan (PhD student), Jörg Behrmann (PhD student), Theresa Leistner (Master Student), Fan Yang (Postdoc), Kang Yang (Postdoc), Daniel Varjas (Postdoc/Researcher), Qing-Dong  Jiang (Postdoc/Researcher), Ipsita Mandal (Researcher).

Recent group alumi include Flore Kunst (PhD & winner of the Arrhenius prize in 2019, next postdoc at MPQ-Harvard), Maximilian Trescher (PhD in 2018, next computer scientist in Berlin),  Zhao Liu (next Thousand Talents Awardee & Asst. Prof. at Zhejiang University), Yaron Kedem (next postdoc with Frank Wilczek), and Johan Carlström (next independent PI at SU). Naemi Florin (next PhD with Bourennane) and Fanny Terrier (next UPMC Paris). 

Earlier project students include Jörg Behrmann (Master 2012-2013), Samuel Sanchez (Master 2012-2013), Maximilian Trescher (Bachelor 2012), Diana Prychynenko (Bachelor 2012 & co-advised Master  2013-2014), Kevin Madsen (Bachelor 2013 & Master 2015-2016), Gregor Pohl (internship project 2013), Alexander Nietner (Master 2014-2015), Gunnar Riemenschneider (Bachelor 2014), Huaiyu Li (internship project 2015), Marlon Rueck (Bachelor 2015),  Irina Gancheva (Master 2015-2016), Jann Launer (Master 2015-2016), David Schneider (Master 2015-2016) and Yann Salimi (Master 2015-2016).

Publications See for publications and links to frequent collaborators.