3 papers
quant-ph2026
The geometry of the Hermitian matrix space and the Schrieffer--Wolff transformation
GergŠPintér, György Frank, Dániel Varjas +1
In quantum mechanics, the Schrieffer--Wolff (SW) transformation (also called quasi-degenerate perturbation theory) is known as an approximative method to reduce the dimension of th…
math-ph2025
Multifold degeneracy points of quantum systems and singularities of matrix varieties
György Frank, András Pályi, GergŠPintér +1
Parameter-dependent quantum systems often exhibit energy degeneracy points, whose comprehensive description naturally lead to the application of methods from singularity theory. A…
cond-mat.mes-hall2025
Birth Quota of Non-Generic Degeneracy Points
GergŠPintér, 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…