Stealth mode

No stealth in space... they say. Heck even NovaGirl93 had to admit to it. But here's someone saying otherwise. Namely: if you're not doing something dumb like firing thrusters, your vessel can direct outgoing infrared to some unobserved direction; thus keeping your vessel (apparently) cooler than it is.

This introduces the wonderful world of non-Hermitian Hamiltonians in photonics. Photonics - the quantum science of how light interacts with atoms - would also, incidentally, explain why we cannot use X-rays to push sails.

Now: I much doubt that the stealth can scale. Your Romulan Warbird have to stay put and drain off as much heat as possible, likely meaning no internal energy even for life-support. Torpedos can't adjust velocity until the last minute. Tungsten rounds from railguns leave the cannon... slowly?

Here is a military use, though: An enemy could drop limpets around a field of rubble. They quietly stick to the target. On a critical mass, boom.

Maybe it will be good mainly for dampening infrared in orbit so that nearby telescopes (like on land) aren't distracted.