Comment on "Heavy Quarkonium in Extreme Conditions"

Understand

In a recent paper (arXiv:1912.02253), Rothkopf claims that the Bryan method, which is widely used to obtain the solution in the maximum entropy method and makes use of the singular value decomposition of a matrix, limits the search space for the solution.

• He even presents a counterexample to the Bryan method.
• In this comment, we first recapitulate the mathematical basis of the Bryan method, and reconfirm that it makes use of no approximations and that it is therefore mathematically rigorous.
• In the second part, we explicitly show that Rothkopf's ``counterexample'' actually does not constitute a counterexample on the basis of the definition of singular value decomposition itself.