LOG#181. Duality and gravity: a short note.

The 2nd superstring revolution circled/circles about (electromagnetic) duality. In D=4 (or general space-time), duality transformations for the electromagnetic field strength read and for the dual field 2-curvature They are true symmetry for the Maxwell equations in vacuum, , and for … Continue reading

LOG#081. Group Theory (I).

I am going to build a “minicourse” thread on Group Theory in this and the next blog posts. I am trying to keep the notes self-contained, since group theory is a powerful tool and common weapon in the hands of … Continue reading