Compactifying a closed string on a circle of radius R is physically equivalent to compactifying on radius α'/R, exchanging momentum and winding modes. No classical-geometry analogue; a genuinely stringy symmetry.
Compactifying a closed string on a circle of radius R is physically equivalent to compactifying on radius α'/R, exchanging momentum and winding modes. No classical-geometry analogue; a genuinely stringy symmetry.