标题： 费米液体的对称性和因果性约束 显示英文标题

标题： Symmetry and causality constraints on Fermi liquids

摘要： 我们研究了相互作用费米液体的对称性和因果性约束。 虽然伽利略或洛伦兹Boost对称性会导致第一个朗道参数$F_1$的一个已知约束，但我们表明尺度不变性同样限制了$F_0$。 对于共形费米液体的情况，我们表明粒子-空穴连续区和零声子的因果性约束强烈限制了相互作用费米液体的可用参数空间。 我们还考虑了非线性响应，这表明即使在长波极限的最低阶，它也对额外的“广义朗道参数”敏感。 我们在这些广义朗道参数上施加了伽利略、洛伦兹和尺度对称性，从而获得了进一步的非线性约束。 我们在几个进入费米液体相的微观模型中测试了这些约束。 显示英文摘要

摘要： We investigate symmetry and causality constraints on interacting Fermi liquids. Whereas Galilean or Lorentz boost symmetry leads to a well-known constraint on the first Landau parameter $F_1$, we show that scale invariance similarly constrains $F_0$. In the case of conformal Fermi liquids, we show that causality constraints on the particle-hole continuum and on zero sound strongly restrict the available parameter space for interacting Fermi liquids. We also consider nonlinear response, which we show is sensitive to additional ``generalized Landau parameters'' even at lowest orders in the long wavelength limit. We impose Galilean, Lorentz and scale symmetry on these generalized Landau parameters, obtaining further nonlinear constraints. We test our constraints in several microscopic models that enter a Fermi liquid phase.