Spin liquid to spin glass crossover in the random quantum Heisenberg magnet
Spin liquid to spin glass crossover in the random quantum Heisenberg magnet
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DOI：
10.1103/physrevb.105.085120
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发表时间：
2022-02-14
影响因子：
3.7
通讯作者：
Sachdev, Subir
中科院分区：
文献类型：
--
作者：
Christos, Maine;Haehl, Felix M.;Sachdev, Subir
本文研究了具有均方根强度J的海森堡交换作用的SU（M）量子自旋。M ->无穷大模型具有量子自旋液体基态，自旋子服从SYK模型的方程。对S = 1/2自旋的SU（2）模型的数值研究表明，在基态下自旋为玻璃有序，但在中频自旋谱中也显示出SYK自旋液体行为。我们采用1/M展开来描述从分数化的费米子自旋到自旋玻璃阶数为q（EA）的束缚自旋玻璃态的跃迁。SYK自旋液体行为持续到类似于J（qEA）的频率ω（*），并且对于ω <ω（*），自旋谱密度在ω中是线性的，因此淬灭自旋液体的广泛的零温度熵。线性CO光谱定性类似于先前使用玻色子自旋大q（EA）。我们认为，广泛的SYK自旋液体熵转化为T -> 0的自旋玻璃态的广泛的复杂性。我们评论全息联系的限制过渡到破碎的黑洞与AdS（2）视界。
We study quantum SU(M) spins with all-to-all and random Heisenberg exchange interactions of root-mean square strength J. The M -> infinity model has a quantum spin liquid ground state with the spinons obeying the equations of the Sachdev-Ye-Kitaev (SYK) model. Numerical studies of the SU(2) model with S = 1/2 spins show spin glass order in the ground state, but also display SYK spin liquid behavior in the intermediate frequency spin spectrum. We employ a 1/M expansion to describe the crossover from fractionalized fermionic spinons to a confining spin glass state with weak spin glass order q(EA). The SYK spin liquid behavior persists down to a frequency omega(*) similar to J(qEA), and for omega < omega(*), the spin spectral density is linear in omega, thus quenching the extensive zero temperature entropy of the spin liquid. The linear CO spectrum is qualitatively similar to that obtained earlier using bosonic spinons for large q(EA). We argue that the extensive SYK spin liquid entropy is transformed as T -> 0 to an extensive complexity of the spin glass state. We comment on holographic connections of the confinement transition to the fragmentation of black holes with AdS(2) horizons.