量子自旋链无阻挫基态上谱隙的改进边界
Improved bounds on the spectral gap above frustration free ground states of quantum spin chains
摘要：
在\cite{Nac2,Nac1}中，Nachtergaele利用"鞅方法“得到了许多无阻挫量子自旋链上的谱隙的显式下界.我们提出了简单的改进，他的主要界限，使之能够获得一个尖锐的下界的频谱间隙以上的自旋1/2铁磁XXZ链。作为该方法的一个例子，我们还计算了AKLT模型的光谱间隙的下限，这是约1/3的预期间隙的大小。
英文摘要：
In \cite{Nac2,Nac1} Nachtergaele obtained explicit lower bounds for the spectral gap above many frustration free quantum spin chains by using the ``martingale method''. We present simple improvements to his main bounds which allow one to obtain a sharp lower bound for the spectral gap above the spin-1/2 ferromagnetic XXZ chain. As an illustration of the method, we also calculate a lower bound for the spectral gap of the AKLT model, which is about 1/3 the size of the expected gap.
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。
