We are theoretical physicists with diverse backgrounds but with a common interest in describing the world — what it is and what it could be — in terms of mathematics. Our main interest is in the exuberant world of quantum mechanics of collective many-body systems. In this context we  bring together insights from different fields of science ranging from high energy physics and abstract mathematics to materials science, photonics and cold atom systems. Three recent examples include 1) foundational work in the new field of non-Hermitian topology incorporating and extending ideas of condensed matter, photonics and topology, 2) the theoretical prediction of novel strongly correlated states of matter, such as fractional Chern insulators, in engineered moiré heterostructures, and 3) analogies with (and subtle but crucial differences from) black holes and new types of anomalies in symmetry breaking semimetals.   

We also work on complex phenomena in the classical realm, presently including novel dynamical effects in optical waveguides and synchronization effects in epidemics. In fact, most of the early experimental manifestations of our ideas in non-Hermitian topology have been in the classical realm although their conceptual provenance lies in (extensions of) quantum physics.

Our emphasis is on curiosity driven basic research, yet we keep alert to possible practical applications of our findings, such as our recent proposal of hyper-sensitive “Non-Hermitian Topological Sensors”.

NEWS: We have several openings. Prospective PhD students can contact the PI by email (emil.bergholtz@fysik.su.se) while potential postdocs can apply here (deadline Nov 1, 2022).

Alumni (with with Emil Bergholtz as main advisor; present members are listed under a separate tab below):

PhD students:

Marcus Stålhammar, PhD 2022; Next: Nordita Fellow

Flore Kunst, PhD 2019, Winner of the Sigrid Arrhenius Prize from Stockholm University as well as the Oseen Medal of the Swedish Physical Society for her PhD thesis; Next: joint postdoc fellowship at MPQ Munich and Harvard & from 2021 group leader at Max Planck (MPI-MPL)

Maximilian Trescher, PhD 2018; Next: computer scientist in Berlin

Jörg Behrmann; Next: permanent staff position at FU Berlin

Postdocs/researchers:
Fan Yang (PhD Ecole Polytechnique, Paris), 2020-2022; Next: Postdoc at EPFL Lausanne

Daniel Varjas (PhD Berkeley), 2020-2022; Next: Researcher at Max Planck (MPI-PKS)

Ipsita Mandal (PhD Harish-Chandra Institute), 2021-2022; Next: Associate Professor at the Polish Academy of Sciences

Qingdong Jiang (PhD Peking University), 2020-2021; Next: Associate Professor at TD Lee Institute, Shanghai

Kang Yang (PhD Paris), 2019-2022; Next: Postdoc at FU Berlin

Johan Carlström (PhD KTH), 2017–2019; Next: VR Starting grant & group leader at Stockholm University

Yaron Kedem (PhD Tel Aviv), 2016–2019; Next: postdoc with Prof. Frank Wilczek at SU

Zhao Liu (PhD CAS Beijing), 2014–2017; Next: Thousand Talents Awardee & Assistant Professor at Zhejiang University

Master students: Theresa Leistner (2020-2021), Fanny Terrier (2019), Naemi Florin (2017), Yann Salimi (2015-2016), Kevin Madsen (2015-2016), Irina Gancheva (2015-2016), Jann Launer (2015-2016), David Schneider (2015-2016), Yann Salimi (2015-2016), Alexander Nietner (shared 2014-2015), Diana Prychynenko (co-advised 2013-2014), Jörg Behrmann (2012-2013) and Samuel Sanchez (2012-2013).

Bachelor students: Marlon Rueck (2015), Huaiyu Li (internship project 2015), Gunnar Riemenschneider (2014), Kevin Madsen (2013), Gregor Pohl (internship project 2013), Maximilian Trescher (2012), Diana Prychynenko (2012).