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

I don't know. In space you couldn't even
toss me a pen, and that was in zero GRAVITY.
The Big Bang Theory Season 8, Episode 3

...who believes loop quantum GRAVITY
better unites quantum mechanics...
The Big Bang Theory Season 2, Episode 2

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

Besides disrupting the local GRAVITY field.
The Big Bang Theory Season 1, Episode 6