The Hall effect: what moves in a metal or a superconductor?

The Hall resistivity has long been used to identify the mobile charge carriers in metals. 
However,  transport theory has failed to explain several intriguing  ‘’Hall anomalies’’ in strongly correlated metals and superconductors.  
Recent advances by our group include new formulas for the Hall coefficient, and a revised theory of flux flow in superconductors, which help us understand the ‘’moving parts’’  in the electrical current of these systems.