Separating a particle's mass from its momentum | Hacker News Reader

Separating a particle's mass from its momentum

arxiv.org

53 pointsbookofjoe17 comments

Oy, veh; that abstract is a mess, even given that IANAphysicist. For instance, I'm thinking that "the counterintuitive result has been obtained that a neutron is" can be replaced by "a neutron can be".

Language matters; if your writing is unnecessarily dense and confusing, your ideas are probably the same, you just don't know it yet.

I noticed something like this in another domain earlier today. The writing was so obtuse. Before sharing I had to edit the quote and make it more direct.

Youre removing the information that the result is counterintertuitive...

Wow, great way of removing context and nuance in a field that requires context and nuance

Is that not provided elsewhere by the report? I'm not against precision of language, and I don't think parent's example was the best, but over-specificity is often a bastion of people who are not sure what they are saying.

"This is not necessarily a detail of relevance, and it is duplicated in the data, but I noticed it and am remarking on it to show that I did not fail to notice this, even if it does not seem to have material importance to this experiment, whose audience should be able to interpret the data for themselves and understand this. However, I have written this to the limit of length and parsable complexity, yet it cannot be said whether I have overstated or understated anything. I am the James Joyce of science, and I justify this part of my value through superficial prolixity."

I blame all those years of 1000-word and 5-paragraph essays.

While not a great sentence by any means, your replacement leaves out the rather important detail that this result has been shown experimentally.

"can be" implies that sometimes a neutron is is measured and sometimes it's not measured, but I don't think that is something the paper is trying to say.

Cough NNT cough

>Language matters; if your writing is unnecessarily dense and confusing, your ideas are probably the same, you just don't know it yet.

Before you get too righteous here: you do realize there are a lot of competent physicists for whom English is not a first language right?

Another interpretation, this is possibly more evidence that TSVF doesn't hold.

https://www.sciencedirect.com/science/article/abs/pii/S03759...

  The two-state vector formalism (TSVF) is a description of quantum mechanics
  in terms of a causal relation in which the present is caused by 
  quantum states of the past, and of the future, taken in combination.

  In TSVF, causality is time-symmetric... 
  TSVF combines causality both 
  from the past (forward causation) 
  and the future (backwards causation, or retrocausality)

https://en.wikipedia.org/wiki/Two-state_vector_formalism

I didn't read it very carefully but I guess this can be translated as,

"If the particle is over here (it probably is), it isn't moving, but if it's over there (very unlikely) it's moving very fast."

Therefore most of the momentum expectation is coming from where the particle probably isn't.

Could this be related to the Heisenberg's uncertainty principle? Or be an artifact caused by the measurement?

Neither. It's simply a counterintuitive consequence of weak measurements in QM, which, if you choose to describe it the way the article does, sounds more counterintuitive than it actually is.

https://en.m.wikipedia.org/wiki/Weak_measurement

Which mass is this referring to? Rest mass, inertial, or a different one?

> we will use a massive particle moving at nonrelativistic speeds

In a non-relativistic the inertial mass and rest mass are the same.

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