4 citations · 9 across the 6 of their papers we have counts for
7 papers
Quantum Phase Transitions in a Generalized Dicke Model
Wen Liu, Liwei Duan
We investigate a generalized Dicke model by introducing two interacting spin ensembles coupled with a single-mode bosonic field. Apart from the normal to superradiant phase transit…
Quotients of graph operators by symmetry representations
Ram Band, Gregory Berkolaiko, Christopher H. Joyner +1
A finite dimensional operator that commutes with some symmetry group admits quotient operators, which are determined by the choice of associated representation. Taking the quotient…
Eigenspaces of symmetric graphs are not typically irreducible
Gregory Berkolaiko, Wen Liu
We construct rich families of Schrödinger operators on symmetric graphs, both quantum and combinatorial, whose spectral degeneracies are persistently larger than the maximal dimens…
Simplicity of eigenvalues and non-vanishing of eigenfunctions of a quantum graph
Gregory Berkolaiko, Wen Liu
We prove that after an arbitrarily small adjustment of edge lengths, the spectrum of a compact quantum graph with -type vertex conditions can be simple. We also show that the ei…
Transformations of polar Grassmannians preserving certain intersecting relations
Wen Liu, Mark Pankov, Kaishun Wang
Let be a polar space of rank . Denote by the polar Grassmannian formed by singular subspaces of whose projective dimension is equal to . Su…
Full automorphism groups of association schemes based on isotropic subspaces
Wen Liu, Mark Pankov, Kaishun Wang
The set of all subspaces of a given dimension in a finite classical polar space has a structure of a symmetric association scheme. If the dimension is zero, this is the scheme of t…
Full automorphism groups of association schemes based on attenuated spaces
Wen Liu, Kaishun Wang
The set of subspaces with a given dimension in an attenuated space has a structure of a symmetric association scheme, which is a generalization of both Grassmann schemes and biline…