在可整合和不可整合的经典旋转链中,非平衡旋转运输.
Dipankar Roy1, Abhishek Dhar1, Herbert Spohn2
1<a href="https://ror.org/0015qa126">International Centre for Theoretical Sciences</a>, Tata Institute of Fundamental Research, Bangalore 560089, India.
Physical review. E
|November 20, 2024
概括
这项研究揭示了古典旋链中的异常旋转运输,与卡达尔-帕里西- (KPZ) 的普遍性保持一致. 在可整合的链中,能量传输仍然是弹道的,但当整合性被打破时,它会变得异常.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 统计力学 统计力学
- 量子动力学 量子动力学是什么?
背景情况:
- 低维旋链中的异常传输为整合性和对称性提供了洞察力.
- 以前的研究将旋转-旋转相关性与卡达尔-帕里西- (KPZ) 的普遍性联系起来.
- 经典旋链中的不平衡旋转运输在很大程度上仍未被探索.
研究的目的:
- 在非平衡条件下研究经典旋转链中的旋转和能量传输.
- 检查可整合和不可整合自旋链中的运输行为.
- 分析被破坏的整合性和自旋对称性对运输特性的影响.
主要方法:
- 将经典的自旋链 (可集成和不可集成) 连接到两个不同温度/磁化级别的储.
- 模拟不平衡稳定状态以测量旋转和能量电流.
- 分析电流的系统大小缩放和可观测的空间配置文件.
主要成果:
- 在可整合和破碎整合 (维护旋转对称性) 情况下观察到自旋电流的异常缩放 (J^s L^-μ),与μ ≈ 2/3 (KPZ类).
- 在纯集成的情况下,能量流仍然是弹道的 (J^e L^-η, η ≈ 0).
- 打破整合性 (不管旋转对称性) 会导致偏离弹性能量传输 (η > 0).
结论:
- 经典旋链中的不平衡旋转运输表现出与KPZ普遍性相一致的异常行为.
- 整合性在确定能量传输特征方面发挥着至关重要的作用,区分弹道和异常模式.
- 整合性,对称性和不平衡条件之间的相互作用显著影响了自旋链中的运输现象.
相关概念视频
01:08Spin–Spin Coupling Constant: Overview
888
In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must...
888
01:03Atomic Nuclei: Nuclear Spin State Overview
876
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of...
876
01:14Atomic Nuclei: Nuclear Spin State Population Distribution
948
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
948
01:08Atomic Nuclei: Nuclear Spin
1.7K
All atomic particles possess an intrinsic angular momentum, or 'spin'. Electrons, protons, and neutrons each have a spin value of ½, although protons and neutrons in nuclei may have higher half-integer spins owing to energetic factors.
Atomic nuclei have a net nuclear spin, , which can have an integer or half-integer value. In atomic nuclei, the spins of protons are paired against each other but not with neutrons, and vice versa. Consequently, an even number of protons does not...
Atomic nuclei have a net nuclear spin, , which can have an integer or half-integer value. In atomic nuclei, the spins of protons are paired against each other but not with neutrons, and vice versa. Consequently, an even number of protons does not...
1.7K
01:17Spin–Spin Coupling: One-Bond Coupling
947
Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
947
01:23Atomic Nuclei: Nuclear Relaxation Processes
629
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis.
629