SciPost Submission Page
Is energy conserved when nobody looks?
by Stanisław Sołtan, Mateusz Frączak, Wolfgang Belzig, Adam Bednorz
This is not the latest submitted version.
Submission summary
| Authors (as registered SciPost users): | Adam Bednorz · Wolfgang Belzig |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/1907.06354v2 (pdf) |
| Date submitted: | 2019-09-25 02:00 |
| Submitted by: | Bednorz, Adam |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Theoretical |
Abstract
Conservation principles are essential to describe and quantify mechanical processes. Classically, the conservation holds objectively because the description of reality can be considered independent of observation. In quantum mechanics, however, invasive observations change quantities drastically, even those conserved classically. Interestingly, we find that the non-conservation is manifest even in weakly measured correlations if some of the observables do not commute with the conserved quantity. Our observation casts some doubt on the fundamental compatibility of conservation laws and quantum objectivity.
Current status:
Reports on this Submission
Strengths
1- Timely topic
2- Nicely written
3- Proper references and positioning
4- Scientifically valid
Weaknesses
1- Dangerous (oversold) conclusions
Report
This is an interesting paper that is reminiscent of recent developments of quantum foundations (contextual objectivity) and quantum thermodynamics (measurement driven engines)
However, I always find dangerous that sentences like "Our observation cast some doubt on the compatibility of conservation laws and quantum objectivity", since both are necessary conditions to practice physics.
In the case of energy, energy can indeed change while measuring an observable which does not commute with the Hamiltonian, but this does not violate the world's energy conservation since the measurement channel provides energy.
Actually, the authors summarize this quite well in their conclusion: Conservation laws are contextual.
Requested changes
1- Milden the last sentence of the abstract