148 citations · 1.2k across the 33 of their papers we have counts for
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Generalizations of the Pfaffian to non-antisymmetric matrices
Daniel Varjas
We study two generalizations of the Pfaffian to non-antisymmetric matrices and derive their properties and relation to each other. The first approach is based on the Wigner normal-…
Pfaffian invariant identifies magnetic obstructed atomic insulators
Isidora Araya Day, Anastasiia Varentcova, Daniel Varjas +1
We derive a topological invariant that extends beyond symmetry eigenvalues and Wilson loops and classifies two-dimensional insulators with a symmet…
Obstructed insulators and flat bands in topological phase-change materials
Quentin Marsal, Dániel Varjas, Adolfo G. Grushin
Phase-change materials are ubiquitous in technology because of their ability to transition between amorphous and crystalline phases fast and reversibly, upon shining light or passi…
Topological defects in a double-mirror quadrupole insulator displace diverging charge
Isidora Araya Day, Anton R. Akhmerov, Daniel Varjas
We show that topological defects in quadrupole insulators do not host quantized fractional charges, contrary to what their Wannier representation indicates. In particular, we test…
Birth Quota of Non-Generic Degeneracy Points
Gergő Pintér, György Frank, Dániel Varjas +1
Weyl points are generic and stable features in the energy spectrum of Hamiltonians that depend on a three-dimensional parameter space. Non-generic isolated two-fold degeneracy poin…
Exceptional dynamics of interacting spin liquids
Kang Yang, Daniel Varjas, Emil J. Bergholtz +2
We show that interactions in quantum spin liquids can result in non-Hermitian phenomenology that differs qualitatively from mean-field expectations. We demonstrate this in two prom…