Timeline for Why do Physicists need unitary representation of Kac-Moody algebra?
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| Jul 4, 2010 at 8:37 | comment | added | jeremy | It's also a consequence in the Kac-Moody case. From the QFT perspective, it's needed in the no-ghost theorems that prevent unitarity from being violated. If we didn't have unitarity, we would break the positive definiteness of our Hilbert space (we would have 'ghosts'). In the Kac-Moody case, the demonstration of this is a little different than my simple example above; but in either case, you can produce negative-norm states through breaking unitarity, which corresponds to a non-Hermitian Hamiltonian. | |
| Jul 4, 2010 at 7:49 | comment | added | Qiaochu Yuan | I don't think Shizhuo is asking about the "unitary" part so much as the "Kac-Moody" part. | |
| Jul 4, 2010 at 7:35 | history | answered | jeremy | CC BY-SA 2.5 |