system
Given the following post, respond as if you're commenting on Reddit:
human
Is it possible to build a truly empty box?

I mean a box that is not just devoid of air or even matter but no photons, neutrinos, nothing. Not even EM fields. 

One obvious problem would be the inside edges of box would occasionally decay and release photons into the box but could they be somehow prevented from travelling too far inside by a large gravitational or EM field outside of the box? 

What's the most empty anything could conceivably be?
gpt
You can't have no EM field. Electromagnetism exists, you have to deal with it. The only thing you can have is the EM field at the lowest possible value. That's what physicists call "vacuum". But even in the vacuum, you still have some energy and some quantum fluctuations. Vacuum is not empty.