A Multicultural Approach to Fractionalization and Electronic Correlations in 2d Materials

10 Aug 2026, 09:00 → 28 Aug 2026, 19:00 Europe/Stockholm

Albano Building 3

Ahmed Abouelkomsan (MIT), Alex Thomson (UC Davis), Emil Johansson Bergholtz (Stockholm University), Hart Goldman (University of Minnesota)

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Venue

Nordita, Stockholm, Sweden

 

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Scope

Recently, there has been an explosion of new discoveries in the realm of 2d Van der Waals materials, kicked off by the observation of the fractional quantum anomalous Hall effect (FQAH) in twisted transition metal dichalcogenides (TMDs) and rhombohedral graphene multilayers. Since this initial discovery, the field has developed rapidly: New experiments have suggested phenomena ranging from chiral superconductivity to exotic charge ordered phases to new kinds of continuous quantum phase transitions beyond the Landau-Ginzburg paradigm, all within the FQAH phase diagram. These observations challenge theorists to reach a global understanding of the interplay of topological order and strong correlation physics in 2d materials, straddling nearly all major areas of quantum condensed matter.

Program Schedule

Timetable

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List of Participants (subject to change)

Annica Black-Schaffer (Uppsala)

Nick Bultnick (Ghent)

Glenn Wagner (ETH)

Tessa Cookmeyer (KITP)

Son Dam (UChicago)

Trithep Devakul (Stanford)

Thors Hansson (SU)

Maria Hermanns (SU)

Dan Mao (Zurich)

Johannes Hofmann (Gothenburg)

Prashant Kumar (IIT Bombay)

Jose Lado (Aalto)

Patrick Ledwith (MIT)

Taige Wang (MIT)

Zhao Liu (Zhejiang)

David Mross (Weizmann)

Anne Nielsen (Aarhus)

Sid Parameswaran (Oxford)

Dan Parker (UCSD)

Leyna Shackleton (MIT)

Steve Simon (Oxford)

Inti Sodemann (Leipzig)

Tomo Soejima (NYU)

Jun Ho Son (Minnesota)

Xueyang Song (Hong Kong)

Oscar Vafek (Minnesota)

Justin Wilson (LSU)

Cenke Xu (UCSB)

Bo Yang (Nanyang)

Yahui Zhang (Johns Hopkins)

Ziyan Zhu (Boston College)

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Organizers:

Ahmed Abouelkomsan (MIT), Hart Goldman (University of Minnesota), Alex Thomson (UC Davis) and Emil Bergholtz (SU)

Sponsored by:

Nordita

Monday 10 August

10:30 → 11:05 Moiré excitons: equilibrium or non

Speaker: Tessa Cockmeyer (UCSB)

11:05 → 11:40 TBD

Speaker: Po-Shen Hsin (Imperial College)

15:15 → 15:45 Coffee Break

Tuesday 11 August

10:30 → 11:05 Relaxation-driven band topology in moiré transition metal dichalcogenide heterobilayers

Speaker: Zoe Zhu (Boston College)

11:05 → 11:40 Solving billion-size topological and correlated super-moire materials with tensor networks

Speaker: Jose Lado (Aalto University)

15:15 → 15:45 Coffee Break

Wednesday 12 August

10:30 → 11:05 Partons and Anyon Superconductivity

Speaker: Steve Simon (Oxford)

11:05 → 11:40 Chiral superconductor near a fractional Chern insulator

Speaker: Taige Wang (Harvard/MIT)

14:00 → 14:35 Coloring in Anyon Superconductivity

Speaker: Hart Goldman (University of Minnesota)

14:35 → 15:10 TBD

Speaker: Xueyang Song (HKUST)

15:15 → 15:50 Coffee Break

Thursday 13 August

10:30 → 11:05 Emergent heavy fermion physics and superconductivity in twisted bilayer graphene

Speaker: Ya-Hui Zhang (Johns Hopkins)

11:05 → 11:40 Finite-size topology

Speaker: Anne Nielsen (Aarhus University)

15:30 → 15:50 Coffee Break

18:30 → 18:50 Dinner

Friday 14 August

10:00 → 10:35 Chern Insulator Boundary Criticality

Speaker: Benjamin Moy (UIUC)

10:35 → 11:10 Rare Regions Win: The Density of States of a Disordered Weyl Semimetal, Exponent and Prefactor

Whether the nodal point of a three-dimensional Weyl semimetal survives weak short-range disorder has been genuinely contested: instanton calculations including fluctuations have claimed that the zero-energy density of states ρ(0) vanishes identically, while exact numerics find it finite. I will show how the question is settled within a controlled saddle-point calculation. In a supersymmetric formulation, the saddle obeys a nonlinear Weyl equation, which I solve in its exact hedgehog j = 1/2 form, and then carry out the fluctuation integral about it in full: every zero mode is accounted for — six bosonic against four fermionic — and the reduced superdeterminant is evaluated as a convergent Fredholm determinant. No fermionic zero mode beyond a Kramers doublet survives to annihilate the result. What emerges is the Nandkishore–Huse–Sondhi form with both its exponent and its absolute prefactor, ρ(0) = A w-4 exp(−s/w2) with s = 6.4163(2) and A = 27.47(8) for Gaussian-correlated disorder, matching exact single-cone numerics over four orders of magnitude with no fitted parameters. The density of states is therefore nonvanishing at any finite disorder strength, and the semimetal–metal transition is avoided rather than critical.

Speaker: Justin Wilson (Louisiana State University)

11:10 → 11:40 Coffee Break

11:40 → 12:15 The long-wavelength correlations of the composite-Fermi surface".

Speaker: Prashant Kumar (IIT Bombay)

Monday 17 August

10:30 → 11:05 Zero-Clustering Geometry in Realistic Fractional Quantum Hall Wave Functions

Speaker: Zhao Liu (Zhejiang University)

11:05 → 11:40 TBD

Speaker: Dan Mao (University of Zurich)

15:15 → 15:35 Coffee Break

Tuesday 18 August

10:30 → 11:05 TBD

Speaker: Dan Parker (UCSD)

11:05 → 11:40 “Exploring correlation physics in M-Point moire materials

Speaker: Sid Parameswaran (University of Oxford)

15:15 → 15:35 Coffee Break

Wednesday 19 August

10:30 → 11:05 TBD

Speaker: Oscar Vafek (University of Minnesota)

11:05 → 11:40 TBD

Speaker: Patrick Ledwith (MIT)

14:00 → 14:35 Skyrmion Fractional Chern Insulators

Speaker: Trithep Devakul (Stanford University)

14:35 → 15:10 Many Crystals in Rhombohedral Graphene

Speaker: Ahmed Abouelkomsan (MIT)

15:15 → 15:50 Coffee Break

Thursday 20 August

10:30 → 11:05 TBD

Speaker: David Mross (Weizmann Institute of Science)

11:05 → 11:40 TBD

Speaker: Hao-Ran Cui (University of Minnesota)

15:15 → 15:35 Coffee Break

Friday 21 August

10:30 → 11:05 Ground-state search as an optimization problem

Speaker: Andre Fonseca (MIT)

11:05 → 11:25 Coffee Break

11:30 → 12:05 Anyon binding at impurities

Speaker: Glenn Wagner (ETH Zurich)

Monday 24 August

10:30 → 11:05 Fractionalization all around: fermions, bosons, and cavities

Speaker: Raul Perea-Causin (Nordita)

11:05 → 11:40 Mapping the quantum limits of classical simulatability

Speaker: Leyna Shakleton (MIT)

15:15 → 15:35 Coffee Break

Tuesday 25 August

10:30 → 11:05 Long-lived modes and hydrodynamic transport in interaction-dominated Fermi liquids

Speaker: Johannes Hofmann (University of Gothenburg)

11:05 → 11:40 TBD

Speaker: Dam Son (University of Chicago)

15:15 → 15:35 Coffee Break

Wednesday 26 August

10:30 → 11:05 Symmetric quantum phase in a spin-1/2 Heisenberg model on the honeycomb lattice

Speaker: Nick Bultnick (Ghent University)

11:05 → 11:40 TBD

Speaker: Tomo Soejima (NYU/Flatiron)

14:00 → 14:35 New insights on 2D chiral many body states from Coulomb gases

Speaker: Inti Sodeman (Leipzig University)

14:35 → 15:10 TBD

Speaker: Hui Liu (Stockholm University)

15:15 → 15:35 Coffee Break

Thursday 27 August

10:30 → 11:05 TBD

Speaker: Bo Yang (NTU)

11:05 → 11:40 TBD

Speaker: Annica Black-Shaffer (Uppsala University)

14:30 → 14:50 Coffee Break

15:15 → 16:15 (Special) AlbaNova Colloquium: The emergent "graviton" in the fractional quantum Hall effect

In fractional quantum Hall states, electrons self-organize into a strongly interacting fluid with nontrivial emergent properties. It has recently been understood that fractional quantum Hall fluids accommodate one or several spin-2 excitations, which have been argued to be condensed-matter analogues of the graviton. In this talk we will review the origin of the idea of the graviton and the basic physics of the fractional quantum Hall effect. We then discuss a recent experiment claiming observation of a graviton-like mode in fractional quantum Hall effect and its broader implications.

Speaker: Dam Son (University of Chicago)

Friday 28 August

10:00 → 18:00 No Talks