Bose-Einstein condensate diagram

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    Bose-einstein Diagram
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Discussion Overview

The discussion revolves around the interpretation of diagrams related to Bose-Einstein condensation, specifically focusing on the meaning of the axes, colors, and height in these diagrams. Participants explore the physical implications of these visual representations in the context of particle velocities and density.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant expresses confusion about the meaning of the axes and colors in Bose-Einstein condensation diagrams and requests clarification.
  • Another participant explains that the diagrams represent particle velocities, with color indicating density, specifically the number of particles with certain velocity components.
  • A reference to a scientific paper is provided, which discusses the observation of Bose-Einstein condensation and describes the diagrams as false color images of the velocity distribution of atoms.
  • It is noted that the condensation occurs in both momentum space and ordinary space due to the trapping of particles, which raises questions about the representation of spatial scales in the diagrams.
  • Participants clarify that both color and height in the diagrams represent the same density information regarding atoms with specific velocities.
  • One participant confirms their understanding of the diagram after the explanations provided.

Areas of Agreement / Disagreement

Participants generally agree on the interpretation of the diagrams regarding color and height representing density, but there are nuances regarding the spatial representation and the implications of the data that remain open for discussion.

Contextual Notes

The discussion highlights potential limitations in understanding due to the complexity of representing both momentum and spatial information in the diagrams, as well as the need for clear references to the original data.

Jufa
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TL;DR
Struggling with Bose-Einstein condensates diagram.
I have seen many of these diagrams in internet and I fail to figure out what their actual meaning is. Can someone explain what the axes and different colours mean? Also, which is the physical interpretation that can be extracted from them? Thanks in advance :).
miguel_bose.png
 
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Jufa said:
many of these diagrams
You could add a reference !

You know what BE condensation means ?

Picture shows particle velocities. Color is density: number of particles with vx, vy in a cell. When it gets colder number of particles with vx=vy=0 increases: they all tend occupy the same QM ground state
 
The original data looks like
bec1_fig2.jpg

Observation of Bose-Einstein Condensation in a Dilute Atomic Vapor
M. H. Anderson, J. R. Ensher, M. R. Matthews, C. E. Wieman, E. A. Cornell
Science, v. 269, no. 5221 (1995), p. 198-201

These are false color images of the velocity distribution of the atoms in the clouds. The image you posted is the same data, but with an added height that is the same as the color map (in other words, color and height represent the same thing, namely the density of atoms with a given velocity).
 
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Note that because Bose-Einstein in achieved here in a trap, the condensation happens not only in momentum space, but also in ordinary space. This is why the figure in the OP cheats a bit by presenting a spatial scale for what should be only velocities.
 
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BvU said:
You could add a reference !

You know what BE condensation means ?

Picture shows particle velocities. Color is density: number of particles with vx, vy in a cell. When it gets colder number of particles with vx=vy=0 increases: they all tend occupy the same QM ground state
If colour stands for the density, what is the height?
 
color = height
 
Jufa said:
If colour stands for the density, what is the height?
DrClaude said:
(in other words, color and height represent the same thing, namely the density of atoms with a given velocity).
 
Perfect, thanks! I do fully understand the diagram now.
 

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