TY - JOUR
TI - Approximation of block numerical range for Hamiltonian operator matrix
AU - Yu Jiahui
AU - Liu Jie
AU - Chen Alatancang
JN - Thermal Science
PY - 2025
VL - 29
IS - 3
SP - 2085
EP - 2093
PT - Article
AB - The aim of this paper is to derive approximations for the block numerical  range of unbounded block operator matrices that are block dominant. To  illustrate our approach, we calculate the quartic numerical range of a  concrete Hamiltonian operator matrix.