# Bell States

1. Sep 23, 2010

### nateHI

Towards the end of http://www.youtube.com/watch?v=IAgV-LKTiMI&feature=channel" video at 54:55, the professor defines the four possible states of two entagled electrons as follows:

singlet
|0,0> = |u,d> - |d,u>
triplet
|1,1> = |u,u>
|1,0> = |u,d> + |d,u>
|1,-1> = |d,d>

where:
|u,u>, |u,d>, |d,u>, |d,d>
form the 4 dimensional basis in the space of the total spin of the two electrons.

This doesn't seem to jive with the four bell states as defiend on wikipedia http://en.wikipedia.org/wiki/Bell_state" [Broken].

For example, the first triplet state of the total spin as defined above |1,1> is an eigenstate of the |u,u> state and doen't need to be superposed. However, every Bell State as defined by wikipedia is a superposition of two states. What am I missing?

Also, which of the four Bell States is the singlet state?

Last edited by a moderator: May 4, 2017
2. Sep 24, 2010