Exact steady state manifold of a boundary driven spin-1 Lai-Sutherland chain

Low-energy physics of isotropic spin-1 chains in the critical and Haldane phases

Using a matrix product state algorithm with infinite boundary conditions, we compute high-resolution dynamic spin and quadrupolar structure factors in the thermodynamic limit to explore the low-energy excitations of isotropic bilinear-biquadratic spin-1 chains. Haldane mapped the spin-1 Heisenberg antiferromagnet to a continuum field theory, the non-linear sigma model (NL$σ$M). We find that the NL$σ$M fails to capture the influence of the biquadratic term and provides only an unsatisfactory description of the Haldane phase physics. But several features in the Haldane phase can be explained by …

Integrable quenches in nested spin chains I: the exact steady states

We consider quantum quenches in the integrable $SU(3)$-invariant spin chain (Lai-Sutherland model) which admits a Bethe ansatz description in terms of two different quasiparticle species, providing a prototypical example of a model solvable by nested Bethe ansatz. We identify infinite families of integrable initial states for which analytic results can be obtained. We show that they include special families of two-site product states which can be related to integrable ``soliton non-preserving'' boundary conditions in an appropriate rotated channel. We present a complete analytical result for t…

Correlation and entanglement spreading in nested spin chains

The past few years have witnessed the development of a comprehensive theory to describe integrable systems out of equilibrium, in which the Bethe ansatz formalism has been tailored to address specific problems arising in this context. While most of the work initially focused on the study of prototypical models such as the well-known Heisenberg chain, many theoretical results have been recently extended to a class of more complicated $\it{nested}$ integrable systems, displaying different species of quasiparticles. Still, in the simplest context of quantum quenches, the vast majority of theoreti…

Matrix product solutions of boundary driven quantum chains

We review recent progress on constructing non-equilibrium steady state density operators of boundary driven locally interacting quantum chains, where driving is implemented via Markovian dissipation channels attached to the chain's ends. We discuss explicit solutions in three different classes of quantum chains, specifically, the paradigmatic (anisotropic) Heisenberg spin-1/2 chain, the Fermi-Hubbard chain, and the Lai-Sutherland spin-1 chain, and discuss universal concepts which characterize these solutions, such as matrix product ansatz and a more structured walking graph state ansatz. The c…

SO(n) Affleck-Kennedy-Lieb-Tasaki 状态作为可积 SU(n) 旋链的共形边界状态

SO(n) Affleck-Kennedy-Lieb-Tasaki states as conformal boundary states of integrable SU(n) spin chains

本文通过 SU(n) ULS 旋链和共形场论构建了具有 SO(n) 对称性的共形边界态，并利用可积性计算了边界熵，揭示了 CFT 与可积晶格模型之间的联系。

相互作用赋予的PT对称性及其对中心自旋模型中退相干、环境诱导退相干选择和非马尔可夫性的影响

Interaction-Endowed PT-Symmetry and its Effects on Decoherence, Einselection, and Non-Markovianity in a Central Spin Model

研究在中心自旋模型中引入PT对称性，通过伪厄密形式和戴森映射研究其对退相干、环境诱导退相干选择及非马尔可夫性的影响，发现γ增加时退相干减缓等现象，且BLP度量有转折点行为。