LOG#211. Understanding gravity (I).

Hi, everywhere! Have you missed me? A little short thread begins. This thread is based on some Nima’s talk on the understanding on gravity. Do we understand gravity? Classically, yes. Quantumly, it is not so easy. String theory is the … Continue reading

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


Joël Scherk (not Schrek, the ogre) was a French theoretical physicist with a tragic death. Perhaps his contributions were short, but they were important in the fields of supersymmetry (SUSY), supergravity (SUGRA) and superstrings. Moreover, he also introduced some crazy … Continue reading