Bogomol'nyi–Prasad–Sommerfield state

In theoretical physics, massive representations of an extended supersymmetry algebra called BPS states have mass equal to the supersymmetry central charge Z. Quantum mechanically, if the supersymmetry remains unbroken, exact equality to the modulus of Z exists. Their importance arises as the supermultiplets shorten for generic massive representations, with stability and mass formula exact.