标题： 由U(1)规范场相互作用引起的非费米液体：功能重整化群分析 显示英文标题

标题： Non-Fermi liquid induced by U(1) gauge field interactions: a functional renormalization group analysis

摘要： 我们研究由二维空间中各向同性、简并的费米气体与U(1)规范场相互作用形成的非费米液体态。 我们的计算使用了带有费米子软频率截断的函数重整化群(fRG)。 我们采用的fRG方案考虑了规范对称性，这在耦合之间施加了关系（修改的Ward-Takahashi恒等式），这些关系限制了RG流。 我们发现的非费米液体的临界指数和耦合常数大多不受是否强制规范对称性约束的影响，这表明这些约束可能是多余的，或者频率截断方案特别稳健。 例外的是规范玻色子质量项，在没有约束的情况下，它在固定点处是RG相关的，但当约束被强制时它是无关的。 后者在物理上是正确的，因为规范对称性不能被自发打破。 此外，我们分别找到了玻色子动力学指数和费米子自能的标度的$z=2$和$\Sigma(\omega,k_F)\sim\omega^{1/2}$。 这些结果与该模型以往的工作结果有很大不同，尽管我们为其合理性进行了论证。 显示英文摘要

摘要： We study the non-Fermi-liquid state formed by an isotropic, degenerate Fermi gas in two spatial dimensions interacting with a U(1) gauge field. Our calculation uses the functional renormalization group (fRG) with a soft frequency cutoff for the fermions. The fRG scheme we employ takes account of the gauge symmetry, which imposes relations (modified Ward-Takahashi identities) between the couplings which constrain the RG flow. The critical exponents and couplings we find for the resulting non-Fermi liquid are mostly insensitive to whether or not we enforce the gauge symmetry constraints, which signifies either that the constraints are superfluous or that the frequency-cutoff scheme is particularly robust. The exception is the gauge-boson mass term, which is RG-relevant about the fixed point without the constraints, but is irrelevant when they are enforced. The latter is physically accurate, as a gauge symmetry cannot be spontaneously broken. In addition, we find $z=2$ and $\Sigma(\omega,k_F)\sim\omega^{1/2}$ for the boson dynamical exponent and scaling of the fermion self-energy, respectively. These results differ considerably from those of past works on the model, though we argue for their plausibility.