Photoemission "experiments" on holographic lattices

Dear Editors, dear Referees,

We have made some minor revisions to the paper in accordance with the suggestions of the referees. A point-by-point response follows.

Referee 1:

Indeed, the index on the right-hand side of Eq. (72) was offset by 1, now it is corrected.

Referee 2:

1) In Fig. 1 we indeed have $Q=1/2$, i.e. all quantities are given in terms of the computational unit $2Q$. At the beginning of Section 4 (i.e. after Figs. 1-3) we state that from now on, i.e. from page 16 onward, we always put $Q=1$. Hence there is no contradiction. 2) The bottom row in Fig. 3 is indeed just the sanity check for the numerics and the implementation of the boundary conditions. It has no physical significance except to remind the reader that the lattice is only sourced by the gauge field and not directly imposed in the metric itself. 3) In the vicinity of the Fermi surface, quadratic imaginary self-energy (and indeed any function which is analytic and even in $\omega$) will certainly give a symmetric peak. Maybe the confusion stems from the fact that, further away from the Fermi surface, there is of course no reason that the peak be symmetric. We have now emphasized that this criterion holds only for reasonably sharp peaks, not far away from the Fermi surface. 4) Indeed we have missed this point in the previous revision. True, computing the spectral function on a very dense grid of momenta would be prohibitively expensive computationally. However, our resolution is not very high: we use a 4x4 grid of momenta (as is often done also in Quantum Monte Carlo calculations of lattice models), hence the curves in Fig. 11 are visibly not completely smooth. While adding more points would of course be advisable, the present result is good enough to show our qualitative conclusions. We have now added this information to the caption of Fig. 11. 5) The relation between the behavior of the self-energy and the spectral function itself is simple in this case (when we are not right at the pole): the larger the imaginary self-energy the smaller the spectral weight. We have mentioned this in the text now.

We hope that the revised manuscript is now acceptable for publication in SciPost Physics Core.

Kind regards,

the authors

1) Corrected typo in Eq. (72).
2) Added emphasis that the symmetry of the peaks is only a good indicator of the character of the quasiparticle sufficiently close to the Fermi surface (footnote 16, page 19).
3) Expanded caption of Fig. 11 now states the spatial resolution in computing the local spectral functions.
4) Added a remark in point 3 at page 27 on the relation between the self-energy and the spectral weight.