4 citations · 7 across the 9 of their papers we have counts for
10 papers
Genus-protected higher-order topological phases
Shahroze Shahab, Hui Liu, Daniel Varjas +1
Higher-order topological phases (HOTPs) feature protected gapless modes on boundaries of higher codimension, such as the corners or hinges of a crystal. They are understood as bein…
AKLT Hamiltonian from Hubbard tripods
Claire Benjamin, Dániel Varjas, Gábor Széchenyi +2
We investigate how the spin-1 Affleck-Kennedy-Lieb-Tasaki (AKLT) Hamiltonian can emerge from a microscopic fermionic model based on half-filled Hubbard tripods. We first show that…
Fermi surface and topology of multiband superconductor BeAu
Riccardo Vocaturo, Klaus Koepernik, Dániel Varjas +3
The chiral material BeAu was recently identified as a multiband type-I superconductor with a critical temperature of 3.2 K. As a member of the B20 crystal family (space group $P2_1…
Effective Hamiltonians for Ge/Si core/shell nanowires from higher order perturbation theory
Sebastian Miles, A. Mert Bozkurt, Dániel Varjas +1
We theoretically explore the electronic structure of holes in cylindrical Germanium/Silicon core/shell nanowires using a perturbation theory approach. The approach yields a set of…
Non-unitary Time Evolution via the Chebyshev Expansion Method
Áron Holló, Dániel Varjas, Cosma Fulga +2
The Chebyshev expansion method is a well-established technique for computing the time evolution of quantum states, particularly in Hermitian systems with a bounded spectrum. Here,…
Multifold degeneracy points of quantum systems and singularities of matrix varieties
György Frank, András Pályi, Gergő Pintér +1
Parameter-dependent quantum systems often exhibit energy degeneracy points, whose comprehensive description naturally lead to the application of methods from singularity theory. A…
Network model for magnetic higher-order topological phases
Hui Liu, Ali G. Moghaddam, Daniel Varjas +1
We propose a network-model realization of magnetic higher-order topological phases (HOTPs) in the presence of the combined space-time symmetry -- the product of a…
The geometry of the Hermitian matrix space and the Schrieffer--Wolff transformation
Gergő Pintér, 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…
Stability of Weyl node merging processes under symmetry constraints
Gabriele Naselli, György Frank, Dániel Varjas +4
Changes in the number of Weyl nodes in Weyl semimetals occur through merging processes, usually involving a pair of oppositely charged nodes. More complicated processes involving m…
Robust quantisation of circular photogalvanic effect in multiplicative topological semimetals
Adipta Pal, Dániel Varjas, Ashley M. Cook
Nonlinear response signatures are increasingly recognized as useful probes of condensed matter systems, in particular for characterisation of topologically non-trivial states. The…