Zero-Point Energy

Zero-point energy is sometimes used as a synonym for the vacuum energy or zero-point field, an amount of energy associated with the vacuum of empty space or the lowest energy state, a field's ground state, which is non-zero. Sometimes it is referred to as the quantum vacuum zero point energy. In cosmology, the vacuum energy is one possible explanation for the cosmological constant. Zero point energy is not controversial although the ability to harness it is.(Wikipedia, the free encyclopedia)