Tachyons and the light barrier

Question

I read somewhere that if something breaks the light barrier, i.e. a tachyon, that it will take infinite energy to make it go slower than the speed of light. So, does that mean that the object will keep gaining speed or will it maintain the speed it was accelerated to?

Answer 1

It will maintain its speed. It's the same as every other object.

Also, making it reach the speed of light will take infinite energy. If you actually calculate out the amount of energy to go slower, you get a complex number.