NMR relaxation in Ising spin chains
NMR relaxation in Ising spin chains
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DOI：
10.1103/physrevb.99.035156
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发表时间：
2018-10
影响因子：
3.7
通讯作者：
Julia Steinberg;N. P. Armitage;F. Essler;S. Sachdev
中科院分区：
文献类型：
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作者：
Julia Steinberg;N. P. Armitage;F. Essler;S. Sachdev
在远低于能隙的温度下，研究了量子Ising链顺磁相在横向场中的低频自旋磁化率。我们发现虚部是由稀有量子过程控制的，其中准粒子的数目以奇数变化。我们得到了具有最近邻Ising相互作用的可积模型在低温极限下的核磁共振弛豫速率的精确结果，并得到了适用于量子临界点附近的一般Ising链的精确通用标度结果。这些结果解决了不同实验探针测量的Ising链体系CoNb$_{2}$O$_{6}$的量子无序顺磁相的能量尺度之间的某些差异。
We examine the low frequency spin susceptibility of the paramagnetic phase of the quantum Ising chain in transverse field at temperatures well below the energy gap. We find that the imaginary part is dominated by rare quantum processes in which the number of quasiparticles changes by an odd number. We obtain exact results for the NMR relaxation rate in the low temperature limit for the integrable model with nearest-neighbor Ising interactions, and derive exact universal scaling results applicable to generic Ising chains near the quantum critical point. These results resolve certain discrepancies between the energy scales measured with different experimental probes in the quantum disordered paramagnetic phase of the Ising chain system CoNb$_{2}$O$_{6}$.