Relativistic quantum strings wrapping around a compact dimension have a mass dependent on the winding $w$ and the momentum $p$, which in turn depend on the radius of the compact dimension $R$. The mass-squared of certain low-energy states can resultantly be written in terms of the radius as:

$M^2 (R) = \frac{1}{R^2} + \frac{R^2}{\alpha^{\prime 2}} - \frac{2}{\alpha^{\prime}}.$

Find the radius $R$ at which these states are massless, i.e. $M^2 = 0$.

**Bonus:** Can you figure out why this is called the *self-dual radius*?

×

Problem Loading...

Note Loading...

Set Loading...