Photo of Enrico Fermi includes math/physics I do not understand

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    Fermi Photo
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Discussion Overview

The discussion revolves around a photograph of Enrico Fermi at a blackboard, which features a geometric drawing and mathematical expressions that participants find difficult to understand. The conversation explores the potential connections between the math and physics concepts, particularly in the context of nuclear physics and quantum mechanics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants note that the equation on the board appears to be the time-dependent Schrödinger equation for a Coulomb potential, like that of a hydrogen atom, but express confusion over its presentation.
  • There is a claim that the equation is meaningless without a state function, \Psi, and that a factor of -\hbar^2 is missing in front of the momentum operator, although this is contested by others.
  • Some participants suggest that the geometric drawing may relate to a coordinate system or a scattering problem, while others speculate it could simply be for a photo opportunity.
  • One participant humorously suggests that Fermi might have been "drunk" or "trolling" with the drawing, indicating skepticism about its seriousness or relevance.
  • Another participant points out that the drawing does not resemble standard representations of quantum mechanical angular momentum, raising questions about its intended meaning.
  • There are references to another photograph of Fermi with a similar drawing, which is associated with energy equations, suggesting a possible connection to the current discussion.
  • One participant speculates that the drawing could represent a water molecule, indicating a variety of interpretations among participants.

Areas of Agreement / Disagreement

Participants express a range of views regarding the meaning and relevance of the math and drawing, with no consensus reached on their significance or connection to physics concepts.

Contextual Notes

Some statements reflect uncertainty about the mathematical expressions and their implications, as well as the context of the drawing. The discussion includes various interpretations and assumptions that remain unresolved.

JLBRECKENRIDGE
The attached jpeg shows Enrico Fermi at the blackboard.

There is a geometric drawing and some math I do not understand.

Can you point me in the right direction?

I have searched for a discussion of what he is presenting but cannot find one.

The photo may be familiar because it was used by the US Postal Service for a stamp honoring Enrico Fermi on the 100th anniversary of his birth.

Thank you!
 

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  • enrico fermi small.jpg
    enrico fermi small.jpg
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This is an infamous photo of Fermi that had been discussed by many people. There is an error in the equation that was written (presumably by him) on the board.

Zz.
 
Zapper,

Does the geometry relate to some aspect of physics? Perhaps something to do with nuclear physics?
 
Well two problems with the first equation. One, as written it's meaningless - the two operators don't really have a meaning unless they're operating on some state, so the omission of \Psi is somewhat strange to me... second, he's missing a factor of -\hbar^2 infront of the momentum operator.

The equation he's written is the time-dependent Schrödinger equation for a Coulomb potential, like that of a hydrogen atom. I don't really know what the diagram he's drawing has to do with it except perhaps depicting a coordinate system.
 
Thank you, dipole and zapper for your responses. Very helpful.

Joseph
 
dipole said:
Well two problems with the first equation. One, as written it's meaningless - the two operators don't really have a meaning unless they're operating on some state, so the omission of \Psi is somewhat strange to me... second, he's missing a factor of -\hbar^2 infront of the momentum operator.

No, there is no missing factor of ##-\hbar^2##. That factor comes from writing the momentum operator out as ##p = -i\hbar \nabla##.
 
Mute, do you agree that the other math on the board has no apparent connection to the geometry drawing?
 
Mute said:
No, there is no missing factor of ##-\hbar^2##. That factor comes from writing the momentum operator out as ##p = -i\hbar \nabla##.

Doh, that's true.
 
JLBRECKENRIDGE said:
Mute, do you agree that the other math on the board has no apparent connection to the geometry drawing?

Without more information it's hard to say for sure. It could be a coordinate system, as dipole suggests; I could imagine it might be a diagram to help illustrate a scattering problem.

He could also just be writing things for a photo op.
 
  • #10
Go home, Enrico. You're drunk.
 
  • #11
lisab said:
Go home, Enrico. You're drunk.

Seriously.

It would be a great stretch to associate the drawing with something about quantum mechanical angular momentum. Maybe that was the idea, but it certainly doesn't look anything like the orthodox representations in most textbooks:

http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/imgqua/vecL.gif
http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/imgqua/vecL2.gif
http://www.google.es/url?sa=i&sourc...qf_gDGVhOyl2jj_6E-_twhXw&ust=1371243073974657
 
  • #12
He was just trolling.
 
  • #13
He was probably thinking, "This circle/triangle thing will definitely drive someone bonkers in 100 years."
 
  • #14
He doesn't draw very good circles. It took some strategic posing and some cropping of the frame to get a half decent picture.
 
  • #15
This link shows another picture of Fermi, younger in age, with same circle drawing on blackboard, but in this version the circle drawing also is associated with energy equations.

http://photos.aip.org/history/Thumbnails/fermi_enrico_a16.jpg
 
Last edited by a moderator:
  • #16
Well, I see a Coulomb potential. So maybe the drawing is a water molecule?
 
  • #17
Salman2 said:
This link shows another picture of Fermi, younger in age, with same circle drawing on blackboard, but in this version the circle drawing also is associated with energy equations.

http://photos.aip.org/history/Thumbnails/fermi_enrico_a16.jpg

He is definitely younger on one of these pictures, probably even by several minutes.
 
Last edited by a moderator:

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