• Register
PhysicsOverflow is a next-generation academic platform for physicists and astronomers, including a community peer review system and a postgraduate-level discussion forum analogous to MathOverflow.

Welcome to PhysicsOverflow! PhysicsOverflow is an open platform for community peer review and graduate-level Physics discussion.

Please help promote PhysicsOverflow ads elsewhere if you like it.


PO is now at the Physics Department of Bielefeld University!

New printer friendly PO pages!

Migration to Bielefeld University was successful!

Please vote for this year's PhysicsOverflow ads!

Please do help out in categorising submissions. Submit a paper to PhysicsOverflow!

... see more

Tools for paper authors

Submit paper
Claim Paper Authorship

Tools for SE users

Search User
Reclaim SE Account
Request Account Merger
Nativise imported posts
Claim post (deleted users)
Import SE post

Users whose questions have been imported from Physics Stack Exchange, Theoretical Physics Stack Exchange, or any other Stack Exchange site are kindly requested to reclaim their account and not to register as a new user.

Public \(\beta\) tools

Report a bug with a feature
Request a new functionality
404 page design
Send feedback


(propose a free ad)

Site Statistics

205 submissions , 163 unreviewed
5,054 questions , 2,207 unanswered
5,345 answers , 22,721 comments
1,470 users with positive rep
818 active unimported users
More ...

  In string-net condensation, what does the quantized charge mean?

+ 3 like - 0 dislike
  1. The electrical charge is quantized strictly for elementary particles. What kind ofconstraints does this fact imply when applied to string-net theory? For this question, I want to understand why electrical charges are quantized instead of having a continuous value. What part of the string-net theory quantize the charge?

  2. Another question is how the end of a broken string generate a field that is almost uniform to different directions? The electron are claimed to be the end of a broken string. I imagine that at the end of a broken string, there should be one special direction, which is where the string is located. Why didn't we see it in electrons? Or is the string is in another dimension so the charge looks the same from all directions in 3D space?

This post imported from StackExchange Physics at 2015-05-14 21:18 (UTC), posted by SE-user CliffX

asked Feb 12, 2015 in Theoretical Physics by CliffX (15 points) [ revision history ]
retagged May 14, 2015

1 Answer

+ 3 like - 0 dislike

In string-net theory, the density of the (oriented) string is a vector field $\vec E$. If string are all closed strings with no end, then $\vec \partial \cdot \vec E =0$. So the ends of the string are the source of $\vec E$, and correspond to the charge. The ends of strings are always discrete, impying that the charge is quantized. i.e. one end = charge-1.

answered Aug 8, 2015 by Xiao-Gang Wen (3,485 points) [ revision history ]

How about the 2nd question? Does it make sense?

Your answer

Please use answers only to (at least partly) answer questions. To comment, discuss, or ask for clarification, leave a comment instead.
To mask links under text, please type your text, highlight it, and click the "link" button. You can then enter your link URL.
Please consult the FAQ for as to how to format your post.
This is the answer box; if you want to write a comment instead, please use the 'add comment' button.
Live preview (may slow down editor)   Preview
Your name to display (optional):
Privacy: Your email address will only be used for sending these notifications.
Anti-spam verification:
If you are a human please identify the position of the character covered by the symbol $\varnothing$ in the following word:
Then drag the red bullet below over the corresponding character of our banner. When you drop it there, the bullet changes to green (on slow internet connections after a few seconds).
Please complete the anti-spam verification

user contributions licensed under cc by-sa 3.0 with attribution required

Your rights