Free-energy Devices
As a scientific concept, the existence of zero-point energy is not controversial although the ability to harness it is. Many people claim to have invented perpetual motion machines and other power generating devices supposedly based on zero-point energy.
In quantum theory, zero-point energy is a minimum energy below which a thermodynamic system can never go. Thus, according to the standard quantum-theoretic viewpoint, none of this energy can be withdrawn without altering the system to a different form in which the system has a lower zero-point energy.
Thus, current claims to zero-point-energy-based power generation systems are in contradiction with known physics laws and have the status of pseudoscience.
One of the theories that claims that zero-point energy is infinite is stochastic electrodynamics. In it, the zero-point field is viewed as simply a classical background isotropic noise wave field which excites all systems present in the vacuum and thus is responsible for their minimum-energy or "ground" states. The requirement of Lorentz invariance at a statistical level then implies that the energy density spectrum must increase with the third power of frequency, implying infinite energy density when integrated over all frequencies. However, as pointed out, this energy can't be withdrawn from the system.
According to a NASA contractor report, "the concept of accessing a significant amount of useful energy from the ZPE gained much credibility when a major article on this topic was recently published in Aviation Week & Space Technology, a leading aerospace industry magazine".
The calculation that underlies the Casimir experiment, a calculation based on the formula predicting infinite vacuum energy, shows the zero-point energy of a system consisting of a vacuum between two plates will decrease at a finite rate as the two plates are drawn together. The vacuum energies are predicted to be infinite, but the changes are predicted to be finite. Casimir combined the projected rate of change in zero-point energy with the principle of conservation of energy to predict a force on the plates. The predicted force, which is very small and was experimentally measured to be within 5% of its predicted value, is finite. Even though the zero-point energy is theoretically infinite, there is as yet no practical evidence to suggest that infinite amounts of zero-point energy are available for use, that zero-point energy can be withdrawn for free, or that zero-point energy can be used in violation of conservation of energy.
Read more about this topic: Zero-point Energy
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