why not dot or comma

why not circle et cetera..

 

why string?

Because it is a theory of 1-d objects.

 

There are either open strings or closed strings.

 

Not sure what you are trying to ask here.

How do open strings look like? Like I- or like C-letter? Do they vibrate as a whole (left-right) or like S-letter?

How do open strings look like? Like I- or like C-letter? Do they vibrate as a whole (left-right) or like S-letter?

 

You can write them down in terms of Fourier-like modes. (Thinking classically here, so I am also restricting attention to bosonic strings)

 

The modes for the closed string can be thought of left and right moving waves circulating around the string.

 

For the open string we have a standing wave, if we pick Neumann boundary conditions. The left and right moving waves are reflected off the boundaries into each other.

 

This will be presented explicitly in any string book.

Edited December 3, 200916 yr by ajb