Some properties of the ferromagnetic XXZ spin chain and their applications to quantum computation

Andreas Klümper

N Kitanine, Jean Michel Maillet, V. Terras

Boqiang Li, Xun Chen, Yuqian Zhao +3 more

The spin-$1/2$ ferromagnetic XXZ chain is a prototypical many-body quantum model, exactly solvable via the integrable Bethe ansatz method, hosting a Tomonaga-Luttinger spin liquid. However, its clear experimental realizations remain absent. Here, we present a thorough investigation of the magnetism of the structurally disorder-free compound $\mathrm{LuCu}{(\mathrm{OH})}_{3}{\mathrm{SO}}_{4}$. By conducting magnetization and electron-spin-resonance measurements on the single-crystal sample, we establish that the title compound approximates the spin-$1/2$ ferromagnetic XXZ chain model with a nearest-neighbor exchange strength of ${J}_{1}\ensuremath{\sim}65\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ and an easy-plane anisotropy of $\ensuremath{\sim}0.994$. The specific heat demonstrates a distinctive power-law behavior at low magnetic fields (with energy scales $\ensuremath{\le}0.02{J}_{1}$) and low temperatures $(T\ensuremath{\le}0.03{J}_{1})$. This behavior is consistent with the expectations of the ideal spin-$1/2$ ferromagnetic XXZ chain model, thereby supporting the formation of a gapless Tomonaga-Luttinger spin liquid in $\mathrm{LuCu}{(\mathrm{OH})}_{3}{\mathrm{SO}}_{4}$.

Bing Tang, Dejun Li

The existence and properties of quantum breathers in a one-dimensional XXZ ferromagnetic Heisenberg spin chain with single-ion easy-plane anisotropy are investigated analytically in the Hartree approximation. We show that the system can support the appearance of quantum breathers, and discuss their existence conditions and properties. In addition, our results show that, for quantum breathers in this system, both the corresponding energy and magnetic moment are quantized.

N Kitanine, Jean Michel Maillet, N. A. Slavnov +1 more

Onofre Rojas, S. M. de Souza, E. V. Corrêa Silva +1 more