Comment on: Calculation of an Enhanced A1gβ Symmetry Mode Induced by
Higgs Oscillations in the Raman Spectrum of High-Temperature Cuprate
Superconductors
In a recent manuscript Phys. Rev. Lett. 127, 197001 (2021) Puviani et al.
claim that the Higgs mode gives an enhancement of the Raman response in the
symmetric A1gβ Raman channel of cuprates. Here we report a series of
technical mistakes in their derivation that completely invalidate this
conclusion. In particular, the Raman response function contains two
renormalized vertices, with a clearly overcounting of diagrams and uncontrolled
results for the Higgs-mode contribution.Comment: Slightly shorter version, accepted for publication in Physical Review
Letter