We investigate the nonequilibrium steady state (NESS) in an open quantum XXZ chain with strong $XY$ plane boundary polarization gradient. Using the general theory developed in [1], we show that in the critical $XXZ$ $|Δ|<1$ easy plane case, the steady current in large systems under strong driving shows resonance-like behaviour, by an infinitesimal change of the spin chain anisotropy or other parameters. Alternatively, by fine tuning the system parameters and varying the boundary dissipation strength, we observe a change of the NESS current from diffusive (of order $1/N$, for small dissipation strength) to ballistic regime (of order 1, for large dissipation strength). This drastic change results from an accompanying structural change of the NESS, which becomes a pure spin-helix state characterized by a winding number which is proportional to the system size. We calculate the critical dissipation strength needed to observe this surprising effect.
Decay of spin helices in XXZ quantum spin chains with single-ion anisotropy
Erlangen National High Performance Computing Center, Friedrich-Alexander-Universität Erlangen-Nürnberg（埃尔朗根国家高性能计算中心，埃尔朗根-纽伦堡大学）；School of Mathematics and Natural Sciences, University of Wuppertal（伍珀塔尔大学数学与自然科学学院）；Institute of Physics, University of Greifswald（格赖夫斯瓦尔德大学物理研究所）
Two-parameter Family-Vicsek scaling in a dissipative XXZ spin chain
University of Oradea（奥拉迪亚大学）；Budapest University of Technology and Economics（布达佩斯技术与经济大学）；National Institute for R&D of Isotopic and Molecular Technologies（同位素与分子技术研究与开发国家研究所）；Eötvös University（厄特沃什大学）
Bethe-ansatz diagonalization of steady state of boundary driven integrable spin chains
University of Ljubljana（卢布尔雅那大学）；University of Wuppertal（伍珀塔尔大学）；Institute of Physics, Chinese Academy of Sciences（中国科学院物理研究所）；Institute of Mathematics, Physics and Mechanics（数学、物理与力学研究所）
Dissipative quantum Ising chain as a non-Hermitian Ashkin-Teller model
我们研究了具有定制体耗散的量子伊辛链，它可以映射到一个非厄米的Ashkin-Teller模型。通过利用Kohmoto-den Nijs-Kadanoff变换，我们进一步将其映射到具有纯虚各向异性参数的交错XXZ自旋链。这使我们能够非常详细地研究原始Liouvillian的本征态。我们表明，在每个奇偶部门的稳定状态是一个完全混合的状态。每一个的唯一性被严格证明。然后我们研究了均匀XXZ链对应的自对偶线上的衰变模式，得到了热力学极限下Liouvillian能隙$ g $（逆弛豫时间）的精确公式.作为耗散强度$ Δ$的函数的能隙$ g $具有尖点，这意味着第一衰减模式的一种相变。
