AI 中文总结
研究两味矩阵 QCD 在高化学势区域的量子相,通过变分技术对角化哈密顿量,发现\(\mu_{_B}\)与\(c\)或\(\mu_{_I}\)主导时调参导致 QPTs,形成复杂相网,部分相类似 LOFF,基态有特定自旋特性,结果与早期预测一致,明确夸克自旋分数占比。
AI 中文摘要
我们研究了双色两味 QCD(矩阵 - QCD₂,₂)在重子(\(\mu_{_B}\))、同位旋(\(\mu_{_I}\))和/或手征(\(c\))化学势较大的区域。在这些区域,哈密顿量大幅简化,使得研究中间和强杨 - 米尔斯耦合下的基态成为可能。通过变分技术对角化哈密顿量,我们表明在\(\mu_{_B}\)和\(c\)(或\(\mu_{_B}\)和\(\mu_{_I}\))主导的区域,调整其余参数会导致量子相变(QPTs)。这些相变形成了一个复杂的相网,每个相都有一个由重子数\(B\)和同位旋\(I\)唯一标记的基态。其中几个相类似 LOFF,其基态携带非零自旋,从而自发打破旋转对称性。这些结果与 Splittorff - Son - Stephanov 的早期有效场论预测一致。这些类似 LOFF 的基态的费米子内容由自旋为 1 的双(反)夸克组成,类似于库珀对。我们计算了夸克携带 的自旋分数,发现它在某些情况下构成了总自旋的很大一部分,甚至几乎是全部。
英文摘要
We investigate the matrix model of two-color two-flavor QCD (matrix-QCD$_{2,2}$) in regimes with large baryon ($μ_{_B}$), isospin ($μ_{_I}$), and/or chiral ($c$) chemical potentials. In these regimes, the Hamiltonian simplifies considerably, making it possible to investigate the ground state for intermediate and strong Yang-Mills coupling. By diagonalizing the Hamiltonian using the variational techniques, we show that in regimes where $μ_{_B}$ and $c$ (or $μ_{_B}$ and $μ_{_I}$) dominate, tuning the remaining parameters leads to quantum phase transitions (QPTs). These transitions form a complex web of phases, each of which has a ground state uniquely labelled by baryon number $B$ and isospin $I$. Several of these phases are LOFF-like, characterized by a ground state carrying non-zero spin and hence spontaneously breaking rotational symmetry. These results are consistent with older effective field theory predictions by Splittorff-Son-Stephanov \cite{Splittorff:2000mm}. The fermionic content of these LOFF-like ground states consists of spin-1 di-(anti-) quarks which are analogous to Cooper pairs. We compute the spin-fraction carried by the quarks and find that it constitutes a significant portion -- in some cases nearly the entirety -- of the total spin.
CommentsLaTeX2e, 23 pages, 15 figures, minor corrections