强关联系统的一种非标准统计：两个简单例子
A nonstandard statistics for strongly correlated systems: Two simple examples
浏览论文内容
中文总结 AI 辅助
探讨强关联费米子统计的两种情况，即非费米液体和统计自旋液体，计算其系统熵与统计分布函数，分析特定填充和温度下情况，特别关注半填充能带时与正常费米液体的差异。
中文摘要 AI 辅助
我们讨论了强关联费米子统计的两种不同情况。第一种是非费米液体（NFL）情况，即排除具有相反自旋（↑↓）的准动量态{k}双重占据的费米子情况。第二种是统计自旋液体（SSL）情况，其中费米子自旋跳跃并与空穴（未占据）态混合。对于这两种情况，我们计算了系统熵和相应的统计分布函数，针对二维方形晶格填充n∈[0,1]和相对温度kBT/|t|进行了分析，其中t<0是最近邻跳跃积分。我们特别感兴趣的是当巡游费米子系统在半填充能带（n→1）时简化为莫特绝缘体状态的情况。这种极限情况表明当前SSL统计与代表正常费米液体状态的无关联费米子统计之间存在质的差异。
英文摘要
We discuss two different cases of strongly correlated fermions statistics. The first of them is the non-Fermi liquid (NFL) case, $i.e.$, that of fermions with exclusion of doubly occupancy of quasimomentum states $\{\bf k\}$ with opposite spins ($\uparrow\downarrow$). The second is that of statistical spin liquid (SSL) case, in which the fermion spins hop around and mix with the holes (unoccupied) states. For both cases we calculate the system entropy and the corresponding statistical distribution function, analyzed for a two-dimensional square-lattice filling $n\in [0,1]$ and relative temperature $k_B T/|t|$, where $t<0$ is the nearest neighbor hopping integral. We are particularly interested in the situation when the system of itinerant fermions reduce to the Mott-insulator state for the half-filled band ($n\to1$). This limiting situation signals a qualitative difference between the present SSL statistics and that of uncorrelated fermions representing normal Fermi-liquid state.
