2009/09/30 by Amit Kumar Pal, Indrani Bose · 14 citations
Computer Science · Mathematics · Physics and Astronomy · #Anisotropy #Condensed matter physics #Ferromagnetism #Hamiltonian (control theory) #Heisenberg model #Mathematics #Pairwise comparison #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum and electron transport phenomena #Quantum entanglement #Quantum mechanics #Qubit #cond-mat.other #cond-mat.str-el #quant-ph
paper · pdf · doi:10.1088/0953-8984/22/1/016004
published in Journal of Physics Condensed Matter 22(1), 016004 (IOP Publishing) · 9 pages, 13 figures, revtex4
openalex publication_date 2009/12/02 · arxiv created 2009/12/03 · arxiv updated 2015/05/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the entanglement properties of a molecular three-qubit system described by the Heisenberg spin Hamiltonian with anisotropic exchange interactions and including an external magnetic field. The system exhibits first-order quantum phase transitions by tuning two parameters, x and y, of the Hamiltonian to specific values. The three-qubit chain is open-ended so that there are two types of pairwise entanglement: nearest-neighbour (nn) and next-nearest-neighbour (nnn). We calculate the ground and thermal state concurrences, quantifying pairwise entanglement, as a function of the parameters x, y and the temperature T. The entanglement threshold and gap temperatures are also determined as a function of the anisotropy parameter x. The results obtained are of relevance in understanding the entanglement features of the recently engineered molecular Cr(7)Ni-Cu(2+)-Cr(7)Ni complex which serves as a three-qubit system at sufficiently low temperatures.