耗散自旋-1/2链中的解禁量子临界点
Deconfined quantum critical point in a dissipative spin-1/2 chain
AI总结：
研究耗散自旋-1/2链中的解禁量子临界性，采用非阿贝尔玻色化、重整化群分析及量子蒙特卡罗模拟确定相图和相变，揭示不同区域临界性质，如欧姆情况的自旋子解禁等，还提出超欧姆区域的转变。
AI中文摘要：
开放量子自旋系统为实现解禁量子临界性提供了一条前所未有的途径。我们考虑一个自旋-1/2的$J$-$Q_3$链，它由反铁磁海森堡交换和有利于价键固体（VBS）态的竞争多自旋相互作用组成，每个自旋分量都与一个玻色子浴耦合。通过非阿贝尔玻色化和重整化群（RG）分析，并结合大规模量子蒙特卡罗（QMC）模拟，我们确定了该模型的相图和相关相变情况。结果表明，对于亚欧姆、欧姆和超欧姆浴，强耗散稳定了反铁磁相。在亚欧姆和欧姆区域增加多自旋相互作用时，可以发现有限耗散下的连续反铁磁-VBS转变。通过微扰RG分析和QMC模拟得到临界性质。在欧姆情况下临界点具有自旋子解禁和涌现的O(4)对称性。在亚欧姆区域，如果自旋子在耗散VBS相中保持解禁，转变也可能涉及自旋子解禁。此外，在超欧姆区域，我们提出了从反铁磁相到准长程有序相的转变。
英文摘要：
Open quantum spin systems offer a previously unexplored route to realizing deconfined quantum criticality. We consider a spin-1/2 $J$-$Q_3$ chain, consisting of an antiferromagnetic (AFM) Heisenberg exchange and a competing multi-spin interaction favoring a valence-bond solid (VBS) state, with each spin component coupled to a bosonic bath. Using non-Abelian bosonization and renormalization-group (RG) analysis, combined with large-scale quantum Monte Carlo (QMC) simulations, we determine the phase diagram and the associated phase transitions of the model. We show that strong dissipation stabilizes an AFM phase for sub-Ohmic, Ohmic, and super-Ohmic baths. Continuous AFM-VBS transitions at finite dissipation are found upon increasing the multi-spin interaction in both the sub-Ohmic and Ohmic regimes. Critical properties are obtained through perturbative RG analysis and QMC simulations. In the Ohmic case, the critical point features spinon deconfinement and emergent O(4) symmetry. In the sub-Ohmic regime, the transition may also involve spinon deconfinement, provided that spinons remain deconfined in the dissipative VBS phase. In addition, in the super-Ohmic regime, we propose a transition from AFM phase to a quasi-long-range ordered phase.
