ar X iv : q ua nt - p h / 07 01 03 2 v 2 3 1 Ju l 2 00 7 SLOCC invariant and semi - invariants for SLOCC classification of four - qubits 1

X iv :q ua nt -p h/ 07 01 03 2v 2 3 1 Ju l 2 00 7 SLOCC invariant and semi-invariants for SLOCC classification of four-qubits 1 Dafa Li, Xiangrong Li, Hongtao Huang, Xinxin Li a Dept of mathematical sciences, Tsinghua University, Beijing 100084 CHINA b Department of Mathematics, University of California, Irvine, CA 92697-3875, USA c Electrical Engineering and Computer Science Department University of Michigan, Ann Arbor, MI 48109, USA d Dept. of computer science, Wayne State University, Detroit, MI 48202, USA Abstract We show there are at least 28 distinct true SLOCC entanglement classes for four-qubits by means of SLOCC invariant and semi-invariants and derive the number of the degenerated SLOCC classes for n-qubits. PACS:03.67.Mn, 03:65.Bz; 03.65.Hk