| 603 | RWTH Publication No: 956748 2022 |
| TITLE | Particle Number Conservation and Block Structures in Matrix Product States |
| AUTHORS | Markus Bachmayr, Michael Götte, Max Pfeffer |
| ABSTRACT | The eigenvectors of the particle number operator in second quantization are characterized by the block sparsity of their matrix product state representations. This is shown to generalize to other classes of operators. Imposing block sparsity yields a scheme for conserving the particle number that is commonly used in applications in physics. Operations on such block structures, their rank truncation, and implications for numerical algorithms are discussed. Explicit and rank-reduced matrix product operator representations of one- and two-particle operators are constructed that operate only on the non-zero blocks of matrix product states. |
| KEYWORDS | second quantization, particle number conservation, matrix product states, matrix product operators |
| DOI | 10.1007/s10092-022-00462-9 |
| PUBLICATION | Calcolo 59, 24 (2022) |
