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TT: Fachverband Tiefe Temperaturen

TT 23: Frustrated Magnets - General

TT 23.9: Talk

Wednesday, September 7, 2022, 17:15–17:30, H22

Entanglement measures of a frustrated spin-1/2 Heisenberg octahedral chain within the localized-magnon approach — •Olesia Krupnitska — Institute for Theoretical Physics, Technical University Braunschweig, D-38106 Braunschweig, Germany — Institute for Condensed Matter Physics, NASU, Svientsitskii Str. 1, 79011 Lviv, Ukraine

The localized-magnon theory [1] is a powerful tool for the rigorous determination of the ground state and detailed study of the thermodynamic properties of a special class of frustrated quantum Heisenberg antiferromagnets at high magnetic fields and low temperatures. We study different measures of two-spin entanglement [2] between the nearest- and between next-nearest-neighbor spins on the square of the spin-1/2 octahedral Heisenberg chain. It was shown that the localized-magnon theory can be modified for simpler calculation of concurrence [3], which may serve as a measure of the bipartite entanglement of the octahedral chain. Furthermore, we calculate the entanglement of formation and the negativity [4] within the localized-magnon concept. We demonstrate that localized-magnon theory can be straightforwardly adapted in order to calculate the respective entanglement measures for a wide class of flat-band quantum Heisenberg antiferromagnets.

[1] J. Schulenburg et al., Phys. Rev. Lett. 88, 167207 (2002).

[2] L. Amico et al., Rev. Mod. Phys. 80, 517 (2008).

[3] J. Strečka, O. Krupnitska and J. Richter, EPL, 132 30004 (2020).

[4] A. Peres, Phys. Rev. Lett. 77, 1413 (1996).