The Unruh Vacuum and the “In-Vacuum” in Reissner-Nordström Spacetime^†

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

I recommend this article be accepted for publication in its current form.

In this article the authors carefully distinguish the in-vacuum state from the Unruh vacuum state.

They argue that the in-vacuum state is the most physically relevant, while the Unruh vacuum state is more of a mathematical convenience, requiring use of the maximum analytic extension of spacetime.

Similarly, the Hartle-Hawking vacuum state is more of a mathematical convenience, not directly of relevance (except as an approximation) to astrophysical black holes. 

Fortunately predictions the  in-vacuum state from the Unruh vacuum state agree at late retarded times.

The article is well-written and I think of interest to the wider black-hole community.

I recommend publication in its current form.

 

Author Response

We thank the referee for the nice report. 

Reviewer 2 Report

Comments and Suggestions for Authors

The authors analyze the Unruh vacuum and the in-vacuum states in a background spacetimes of a Reissner-Nordstrom metric. They point out similarities and differences concerning the two vacumm states. In particular, they proceed with the analysis for both extremal and non-extremal black holes.

In general, the paper is well written and I recommend the paper for publication as is concerning the scientific content. In my opinion, the authors could improve the manuscript by including more references.

Comments on the Quality of English Language

A few typos were found and should be corrected ("can be seem" in page 10; "of of" in page 14; "innter" in page 19; "dos not" in page 20). Several commas seem to be missing throughout the text (although the readability is not compromised) - I suggest a revision by the authors.

Author Response

As suggested by the referee, we have corrected the typos, inserted commas in the text, and we have added references. 

Author Response File: Author Response.pdf