Partial scaling transform of multiqubit states as a criterion of separability
Cosmo Lupo, Vladimir I. Man’ko, Giuseppe Marmo, E. C. G. Sudarshan · Journal of Physics A Mathematical and General · 2005
The partial scaling transform of the density matrix for multiqubit states is introduced to detect entanglement of quantum states. The transform contains partial transposition as a special case. The scaling transform corresponds to partial time scaling of subsystem (or partial Planck's constant scaling) which was used to formulate recently separability criterion for continous variables.A measure of entanglement which is a generalization of negativity measure is introduced being based on tomographic probability description of spin states.