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arXiv 1305.0352cond-mat.stat-mech
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有限三角晶格上XY量子反铁磁体自发对称性破缺的数值研究

Numerical Study on Spontaneous Symmetry Breaking in a XY Quantum Antiferromagnet on a Finite Triangular Lattice

Tomo Munehisa, Yasuko Munehisa

摘要:

最近的实验需要更复杂的宏观波函数,我们利用变分Monte Carlo方法和随机态选择方法对有限三角晶格上的XY量子反铁磁体进行了数值研究.我们的目的之一是数值证实Nambu-Goldstone玻色子在低能激发下的优势。另一方面,通过固定对称性的量子数,计算了自旋的能量、对称性破缺算符的期望值和结构函数。这些计算是对无限大晶格中的简并态进行的。通过数值计算,我们证实了Nambu-Goldstone玻色子的存在,并发现了上述量与量子数平方的依赖关系。利用这些结果可以讨论量子自旋系统中复杂的宏观波函数。

英文摘要:

Motivated by recent experiments that require more complicated macroscopic wave functions in the condensed matters, we make numerical study on a XY quantum antiferromagnet on a finite triangular lattice using the variational Monte Carlo method and the stochastic state selection method. One of our purpose is a numerical confirmation on dominance of a Nambu-Goldstone boson in low energy excitation. For another purpose, we calculate energy, an expectation value of a symmetry breaking operator and structure functions of spin by fixing a quantum number of the symmetry. These calculations are made for states that become degenerate in an infinitely large lattice. By numerical calculations we confirm existence of a Nambu-Goldstone boson, and find dependence of a square of the quantum number for the above quantities. Using these results we can discuss on complicated macroscopic wave functions in quantum spin systems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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