Is it possible to create a "cold weapon" that holds enough power match modern firearms?
My first thought was coilguns and railguns as they do not rely on controlled explosions but I remembered that electricity and friction with the air would still produce enough heat to register in thermal cameras.

If possible, plese also suggest me a weapon that can be hide from visual, thermal, and sonar sensors. Even conceptual designs are fine, please. Pretty please.
I need it.