Question

Have researchers have now been able to cool substances to absolute zero

Answer 1

It's a law of nature, which I don't understand too well, that we can
cool things as close to Absolute Zero as we want to, but we can
never get all the way there. 

I think that individual atoms and molecules have been cooled in
the laboratory to within a few thousandths of a Celsius degree
of it ... actually not too shabby an accomplishment !
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WOW !  I just went and searched online for more information
on this subject.  (You can't imagine what great stuff you can find
by doing that.  You ought to try it some time.)

The 1997 Nobel Prize in Physics was awarded to a team of three
physicists who invented a method of using lasers to slow down the
motion of atoms, and that's the same thing as cooling them.  They
were able to cool some atoms to a temperature of 240 millionths
of a degree above Absolute Zero !