Quantum Beam Scattering—Beam’s Coherence Length, Which-Path Information and Weak Values

Round 1

Reviewer 1 Report

The draft is unusual and very rarely seen in the scientific literature. The presented results are relatively old from one point, but the described concept is new and offers a revolutionary interpretation of obtained experimental data.

Also, in the time of the second quantum revolution, it is vital to have a paper that reveals unexplained and, very often by purpose, ignored the signature of quantumness in the interaction of the particles/light with matter.

Additionally presented draft offers the link between neutron scattering and quantum optics and how well-defined concepts in quantum optics can be used to explain neutron experiments.

Regarding technical issues:

First, Fermig Golden is often used to describe radiation dynamics in photonics, practically connecting electronic transition/properties of molecules with a density of optical states(environment). In this sense, Fermi's golden rule is way behind the classical approach and allows coupling/correlations with the environment.

The second results are clearly written, and the concept of WV formalism is very well described. Personally, I consider it challenging and appealing to exploit the idea of WV in scattering, and I fully agree with the authors that neutrons, in the case of INS experiments, should be considered quantum objects. However, I found the discussion a bit confusing, especially the part discussing QE as caused for observed reduced intensity and connecting this 'old' approach  with modern quantum mechanics and weak value concept. Please re-write this part.

The conclusion paragraph needs to be included.

Ultimately, I am recommended a minor but obligatory revision of this draft.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Review for qubs-2424160 “Quantum beam scattering—Beam’s coherence length, Which-path information, and Weak Values” from C. Aris Chatzidimitriou-Dreismann

 

The author reviews the conventional theory of neutron beams interacting with many-body systems and compares it to using modern quantum theoretical approaches like quantum entanglement, von Neumann measurements, weak values. Thus, he shows how momentum-transfer deficit and an intensity deficit in neutron scattering on protons of hydrogen-containing samples can be explained using new observables for describing non-relativistic quantum beams.

 

This is a very interesting paper reviewing the basics of neutron scattering in the light of theoretical well-established concepts from the filed of quantum entanglement in quantum computing. These effects could explain hitherto unexplained effects in neutron beam scattering of hydrogen-containing samples. Thus, even being partly a speculative approach, such an idea and its possible consequences for the field of scattering experiments is certainly well suited for publication in QuBS. The paper is well written and the argumentation can easily be followed also for non-theoreticians like me.

 

One question remains open for me as the vast majority of experiments on hydrogen-containing can be explained with the standard scattering theory, why this not the case for the specific example shown by the author. It would be very helpful if this could be emphasized even more in the manuscript. Furthermore, there a few minor issues:

 

1.    In neutron scattering usually Q is used to describe the momentum transfer. Here the author has chosen K, which makes the formulae looking a bit strange to read. 

2.    In line 349 in the formula there is twice a “=” sign. Please correct or insert the missing part.

 

3.    There are a few typos and punctuation errors in the text, please correct.

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Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

I have carefully reviewed the manuscript titled "Quantum beam scattering—Beam’s coherence length, which-path information, and Weak Values" that was submitted to Photonics for publication. The manuscript explores the coherence length, which-path information, and Weak Values of neutron beams, focusing on the limitations of conventional theories and the connection to modern quantum theoretical approaches. While the topic is interesting, the article lacks clarity, fails to effectively present new theoretical methods, and does not sufficiently summarize or discuss the obtained results. Furthermore, the provided figures are of low quality and sourced from previously published articles. The overall structure of the manuscript is disorganized, and the language style does not conform to the standards of scientific literature, making it challenging to understand the contributions and innovations presented. Therefore, I recommend rejection of this manuscript.

 

Detailed comments:

 

Abstract: The abstract contains excessive background information, much of which is outdated and extensively covered in textbooks. The main focus and key findings of this article are not adequately highlighted. I suggest the authors revise and add more emphasis on the primary work and results.

 

Introduction: The first paragraph cites statements attributed to Einstein and Schrödinger, as well as the statement from the Nobel Prize in Physics 2022. It is necessary to provide references for these citations.

 

Figure 1: The fonts used in Figure 1 would benefit from alignment and standardization. It is advisable to use black for the coordinate axes to avoid confusion with the blue curve.

Comments for author File: Comments.docx

Writing Style: The overall writing style of the manuscript lacks the technical rigor expected of a scientific paper. Numerous grammar and punctuation errors exist throughout the text. For instance, an additional period is present at the beginning of Line 37, and a comma is missing before "new observable effects" in Line 9. The authors should carefully revise the manuscript to adhere to the appropriate scientific writing conventions and standards.

Author Response

please see the attachment

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

After making the modifications, I think this paper can be accepted.