Quantum Uncertainty Questions (HUP)

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Homework Help Overview

The discussion revolves around quantum mechanics, specifically focusing on the Heisenberg Uncertainty Principle (HUP) and its implications for measuring position and momentum. The original poster presents two questions related to the precision of velocity measurement for a dust grain and the feasibility of a device claiming extreme accuracy in momentum measurement.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants question the validity of the claims made in the original poster's questions, suggesting potential misunderstandings of quantum mechanics and the HUP. There are inquiries about the source of the questions and whether relevant equations exist in the referenced material.

Discussion Status

The discussion is ongoing, with participants expressing skepticism about the accuracy of the claims regarding the measuring device and seeking clarification on the source of the questions. There is no clear consensus, but the dialogue indicates a critical examination of the assumptions underlying the problems presented.

Contextual Notes

Some participants note the absence of equations in the original poster's reference material, which may contribute to misunderstandings about the problems posed. The nature of the questions suggests a need for deeper exploration of quantum mechanics concepts.

vintagelover007
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Homework Statement
This is a homework assignment for my Modern Physics Class, I cannot find where to start in my textbook or class notes.
Relevant Equations
There are no equations that appear.
a) Consider a dust grain of mass 0.1µg whose position is known to a distance of 1µm. How precisely can its velocity be known?

b) A company claims to have invented a device that can measure the momentum of objects inside it with extreme accuracy. The device fits within a matchbox, and the claimed precision with which it can measure momentum is δp = ±10^−26kg ms−1 .

Explain why the claimed performance cannot possibly be accurate, and estimate the smallest possible size of a device with such momentum precision, according to laws of quantum physics.
 
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vintagelover007 said:
There are no equations that appear.

Really? Anywhere in the book? No equations?
What book is this?
 
These questions seem to be based on several fundamental misunderstandings of QM and the HUP.

Where did you get these questions?
 
Vanadium 50 said:
Really? Anywhere in the book? No equations?
What book is this?
There are equations in the book, I just can't find anything close to this problem.
 

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