Relation between the entropy and the linear entropy in the ion–laser interaction

Information diagrams in the study of entanglement in symmetric multi-quDit systems and applications to quantum phase transitions in Lipkin–Meshkov–Glick D-level atom models

“…From the expression of the extremal density matrices (1,2), or their alternative expressions (3,4), and the expression of the inner curves ρ(k) min ( ), it is clear that, for a given value of the linear entropy and a fixed rank k + 1, the extreme values of the von Neumann entropy are reached for k identical eigenvalues. If the remaining eigenvalue is larger than the rest (i.e.…”

“…In Ref. [3], a comparison is made between both entropies in the case of two qubits (see also [4] for the case of the ion-laser interaction). In [5], a detailed study of information diagrams is carried out for arbitrary pairs of entropies.…”

“…Section 3 reviews the concept of U (D)-spin coherent states and their Z D−1 2 parity adapted version, the DCAT. In Sect. 4 we compute one-and two-quDit RDMs for the 2CAT and the 3CAT, their Linear and von Neumann entropies, plotting them and constructing the associated information diagrams. In Sect.…”

Information diagrams in the study of entanglement in symmetric multi-quDit systems and applications to quantum phase transitions in Lipkin-Meshkov-Glick D-level atom models

“…(1,3) and λ = 1− k for eqns. (2,4). In most cases, the pair of entropies (L, S) is considered, where L and S denote linear and von Neumann entropies, respectively.…”

Linear entropy in the atom-field interaction at finite temperature

“…Calculation of this quantity, however, may become a difficult task as mentioned before. A more convenient quantity to calculate because of its simplicity that however may be used as it gives information about the purity of any of the susbsystems, atom and field, is the linear entropy [16], defined as…”