Zero Point Energy

Zero-point energy is the lowest possible energy that a quantum mechanical physical system may have; it is the energy of its ground state. All quantum mechanical systems undergo fluctuations even in their ground state and have an associated zero-point energy, a consequence of their wave-like interaction.

Because of the uncertainty principle, every physical system (even at absolute zero temperature) has a zero-point energy that is greater than the minimum of its potential well. Liquid helium-4 (4He) remains liquid—it does not freeze—under atmospheric pressure no matter how low its temperature is, because of its zero-point energy.

The concept of zero-point energy was developed in Germany by Albert Einstein and Otto Stern in 1913, using a formula developed by Max Planck in 1900. The term zero-point energy originates from the German Nullpunktsenergie. The German name is also spelled Nullpunktenergie (without the "s")

Vacuum energy is the zero-point energy of all the fields in space, which in the Standard Model includes the electromagnetic field, other gauge fields, fermionic fields, and the Higgs field. It is the energy of the vacuum, which in quantum field theory is defined not as empty space but as the ground state of the fields. In cosmology, the vacuum energy is one possible explanation for the cosmological constant. A related term is zero-point field, which is the lowest energy state of a particular field.