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arXiv 2102.09089hep-thcond-mat.str-elcond-mat.supr-con
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平面狄拉克材料中的级联相变

Cascade of phase transitions in a planar Dirac material

Takuya Kanazawa, Mario Kieburg, Jacobus J. M. Verbaarschot

备注：
44 pages. v2: references added
发表信息：
J. High Energ. Phys. 2021, 15 (2021)
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摘要：

本文研究了具有$M$味和具有$\mathrm{U}(M)\times \mathrm{SU}(N)$对称性的$N$色的$2+1$维中相互作用狄拉克费米子模型。在大- $N$极限下，我们发现$\mathrm{U}(M)$对称性以多种方式自发破缺.在真空中，当宇称破缺的味单重态质量变化时，基态经历一系列$M$一级相变，经历以$\mathrm{U}(M)\to \mathrm{U}(M-k)\times \mathrm{U}(k)$与$k\in\{0,1,2,\cdots,M\}$对称破缺为特征的$M+1$相，与三维QCD的真空结构非常相似。在有限的温度和化学势下，观察到一个丰富的相图，一级和二级相变和三临界点。还存在具有$\mathrm{U}(3)\to \mathrm{U}(1)^3$、$\mathrm{U}(4)\to \mathrm{U}(2)\times \mathrm{U}(1)^2$和$\mathrm{U}(5)\to \mathrm{U}(2)^2\times \mathrm{U}(1)$形式的自发对称性破缺的奇异相。对于一个大的味道单重态质量，增加的化学势$μ$带来$M$连续的一阶跃迁，分离的低$μ$相图与消失的费米子密度从高$μ$区域与高费米子密度。

英文摘要：

We investigate a model of interacting Dirac fermions in $2+1$ dimensions with $M$ flavors and $N$ colors having the $\mathrm{U}(M)\times \mathrm{SU}(N)$ symmetry. In the large-$N$ limit, we find that the $\mathrm{U}(M)$ symmetry is spontaneously broken in a variety of ways. In the vacuum, when the parity-breaking flavor-singlet mass is varied, the ground state undergoes a sequence of $M$ first-order phase transitions, experiencing $M+1$ phases characterized by symmetry breaking $\mathrm{U}(M)\to \mathrm{U}(M-k)\times \mathrm{U}(k)$ with $k\in\{0,1,2,\cdots,M\}$, bearing a close resemblance to the vacuum structure of three-dimensional QCD. At finite temperature and chemical potential, a rich phase diagram with first and second-order phase transitions and tricritical points is observed. Also exotic phases with spontaneous symmetry breaking of the form as $\mathrm{U}(3)\to \mathrm{U}(1)^3$, $\mathrm{U}(4)\to \mathrm{U}(2)\times \mathrm{U}(1)^2$, and $\mathrm{U}(5)\to \mathrm{U}(2)^2\times \mathrm{U}(1)$ exist. For a large flavor-singlet mass, the increase of the chemical potential $μ$ brings about $M$ consecutive first-order transitions that separate the low-$μ$ phase diagram with vanishing fermion density from the high-$μ$ region with a high fermion density.

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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