The Role of Axions in the Formation of the Photoluminescence Spectrum in Dispersive Media

Round 1

Reviewer 1 Report

Dear Author,

The paper, which aims to review experiments on photoluminescence in dispersive media and propose the involvement of axions in the process, would benefit from a major revision to make the contents more clear (motivation, peculiarity of the results, model proposed). After that, more specific comments about rephrasing and style could be addressed.

Major points:

1) The hypothesis of axions being involved in the photoluminescence process is not clear and does not show enough scientific explanation in the current status of the manuscript. A model is referred in several instances in the paper but it is never presented in its entireness (only references to previous works of the author are cited). In this current status of the manuscript the involvement of axions is not supported enough to be part of the title which at the moment could be "Studies of Photoluminescence in dispersive media". The description of axions as solution of the strong CP-problem is completely missing and it is not clear in which way they become part of the photoluminescence experiments reviewed.

2) The paper is not well organized, many parts are too long and there is no clear explanations of the experiments reviewed in Section 5. The Introduction mentions in line 82 that the aim of the review is to present a model reflecting the contributing of axions to the PL process but such a model is not present in the paper. It is necessary to clarify what is the non-conventional behaviour observed in the experiments and how it could be explained by axions. If it is not possible to produce a solid model, than the paper should focus on the review of the experiments and on the peculiarity of results (which is not completely clear from the text) and propose the axion idea as a possible explanation, but not as the main focus of the paper.

3) Even if references are present and distributed along the text, the author do not explains clearly which is the message of the respective references so for a reader is difficult to put together the information. References are useful if one wants to go and check in more detail but there should be more context in order to be able to follow. An example: in the first line of the Introduction it is written: "The review is dedicated to PL and the axion problem." and 5 references are indicated, which are completely different one from the other. What is the axion problem mentioned in this sentence? It looks like the reader can find about it reading those 5 references but more context would help to clarify.

5)Many key references are in Russian, making impossible to be understood by non Russian speaking colleagues. This makes necessary to explain in more detail the passage of those references which are key for the discussion  and possibly accompany those references with others in English covering the same problem.

 

Minor points:

a)Many expressions which are personal views of the author should be avoided in order to reach a less colloquial form of the text. For instance line 40 "in the author's opinion". In particular the Introduction is very colloquial and presents several points of view of the author while it would be more effective if focused on the topics of the review, in particular on the problem of the interpretation of the experiments of photoluminescence in dispersive media

b)words as "fusion", "birth" or "elementary act" are not appropriate for describing the mentioned processes (annihilation, decay, generation are more appropriate depending on the context)

c)Some references are missing (35,46,50)

d)ref. 32 cites Wikipedia, but better to cite a scientific work on which the Wikipedia page is based

 

 

 

Author Response

Please find the answers attached.

Author Response File: Author Response.docx

Reviewer 2 Report

The present paper considers an untraditional interpretation of photoluminescence in several dispersive media. A detailed review of the basic principles of conventional photoluminescence is given, along with a summary of experimental results. Limits on the axion lifetime are presented. The discussed topics of research are certainly interesting. However, the details of the analysis relating to axions are not presented clearly and transparently. Which value(s) of the axion-diphoton interaction strength does the author assume in their analysis? If this interaction strength is very small, then axions would not appreciably contribute to the photoluminescence phenomenon (in the limit of zero interaction strength, no virtual axions could be produced, so there would be no contribution to the photoluminescence processes in this limiting case). There are existing limits on the strength of the axion-diphoton interaction strength from different studies, which may be used to check the self-consistency of the author’s central claim. These limits are tabulated in various places, for example the biennial review on Axions by the Particle Data Group.

Author Response

Please find the answers attached.

Author Response File: Author Response.docx