# How would behave theoretical matter with negative mass? [duplicate]

I wonder if there is any possibility to evaluate theoretical characteristics of matter with negative mass? This is not thing of anti-mass but classical matter just with negated weight. I thing that if you would put it on surface of the Earth it would fly to heaven, wouldn't it? Could this be space-freedom redefined problem solution or am I just curious too much? Can't we simply use working functions/formulas with negate mark?

Let's take a quick look at QFT (the commonly accepted theory of matter and fundamental forces - everything except gravity). For bosons, the mass-defining parameter in the Lagrangian is $m^2$. One can either make $m^2$ less than zero (which would make your field tachyonic) or greater than zero, which does not fix the sign of $m$. So basically, there is no way of having negative-mass bosons in QFT. Same goes for fermions, where you can specify $m$ explicitly, but the observable mass is just the absolute value of this $m$.