
What about loop quantum GRAVITY?
The Big Bang Theory Season 7, Episode 20

The idea that you might be able
to incorporate GRAVITY...
The Big Bang Theory Season 2, Episode 6

And how you threw up
in zero GRAVITY,
The Big Bang Theory Season 7, Episode 16

...for this university's
six-loop quantum GRAVITY calculations.
The Big Bang Theory Season 6, Episode 9

I really miss GRAVITY.
The Big Bang Theory Season 6, Episode 3