View source for Type 0 string theory

The '''Type 0 string theory''' is a less well-known model of [[string theory]]. It is a [[superstring theory]] in the sense that the [[worldsheet]] theory is [[supersymmetric]]. However, the [[spacetime]] spectrum is not supersymmetric and, in fact, does not contain any [[fermion]]s at all. In dimensions greater than two, the ground state is a [[tachyon]] so the theory is unstable. These properties make it similar to the [[bosonic string]] and an unsuitable proposal for describing the world as we observe it, although a GSO projection does get rid of the tachyon and the even [[G-parity]] sector of the theory defines a stable string theory. The theory is used sometimes as a [[toy model]] for exploring concepts in string theory, notably [[closed string]] [[tachyon condensation]]. Some other recent interest has involved the [[two-dimensional string theory|two-dimensional Type 0 string]] which has a non-perturbatively stable matrix model description.

Like the [[Type II string]], different [[GSO projection]]s result in slightly different theories, Type 0A and Type 0B. The difference lies in which types of [[Ramond–Ramond field]]s lie in the massless spectrum.

== References ==
* [[Joseph Polchinski|Polchinski, Joseph]] (1998). ''String Theory'', Cambridge University Press. A modern textbook.
** Vol. 2: Superstring theory and beyond. {{ISBN|0-521-63304-4}}.

[[Category:String theory]]


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