January 0 ?

January 0, yes. They didn't want to refer to the 31st December of the previous year, so that metrologists f this time introduced this January 0 day.

The idea of cooling with lasers is a bit like counter-intuitive.. but so ... mmm cool ! ;)

This relies on the radiative pressure of the electromagnetic field associated with the laser that can slow down (and thus cool down) the atom.