Editing Zero-point energy (section)

=== Casimir batteries and engines ===
A common assumption is that the [[Casimir effect|Casimir force]] is of little practical use; the argument is made that the only way to actually gain energy from the two plates is to allow them to come together (getting them apart again would then require more energy), and therefore it is a one-use-only tiny force in nature.<ref name=army/> In 1984 [[Robert L. Forward|Robert Forward]] published work showing how a "vacuum-fluctuation battery" could be constructed; the battery can be recharged by making the electrical forces slightly stronger than the Casimir force to reexpand the plates.<ref>{{cite journal|last1=Forward|first1=Robert L.|title=Extracting electrical energy from the vacuum by cohesion of charged foliated conductors|journal=Physical Review B|date=1985|volume=30|issue=4|page=1700|doi=10.1103/PhysRevB.30.1700|bibcode=1984PhRvB..30.1700F}}</ref>

In 1999, Pinto, a former scientist at [[NASA]]'s [[Jet Propulsion Laboratory|Jet Propulsion Laboratory at Caltech]] in Pasadena, published in ''[[Physical Review]]'' his [[thought experiment]] (Gedankenexperiment) for a "Casimir engine". The paper showed that continuous positive net exchange of energy from the Casimir effect was possible, even stating in the abstract "In the event of no other alternative explanations, one should conclude that major technological advances in the area of endless, by-product free-energy production could be achieved."{{sfnp|Pinto|1999}}

Garret Moddel at [[University of Colorado Boulder|University of Colorado]] has highlighted that he believes such devices hinge on the assumption that the Casimir force is a [[Conservative force|nonconservative force]], he argues that there is sufficient evidence (e.g. analysis by Scandurra (2001)<ref>{{cite arXiv|last1=Scandurra|first1=M.|title=Thermodynamic properties of the quantum vacuum|eprint=hep-th/0104127|year=2001}}</ref>) to say that the Casimir effect is a conservative force and therefore even though such an engine can exploit the Casimir force for useful work it cannot produce more output energy than has been input into the system.<ref>{{cite journal|last1=Moddel|first1=Garret|last2=Dmitriyevaa|first2=Olga|title=Extraction of Zero-Point Energy from the Vacuum: Assessment of Stochastic Electrodynamics-Based Approach as Compared to Other Methods|journal=Atoms|volume=7|issue=2|at=51|arxiv=0910.5893|year=2009|doi=10.3390/atoms7020051|s2cid=17095906|doi-access=free}}</ref>

In 2008, [[DARPA]] solicited research proposals in the area of Casimir Effect Enhancement (CEE). The goal of the program is to develop new methods to control and manipulate attractive and repulsive forces at surfaces based on engineering of the Casimir force.<ref>{{Cite web |date=2008 |title=Research in a Vacuum: DARPA Tries to Tap Elusive Casimir Effect for Breakthrough Technology |url=https://www.scientificamerican.com/article/darpa-casimir-effect-research/ |access-date=2024-02-22 |website=www.scientificamerican.com |publisher=Scientific American}}</ref>

A 2008 patent by Haisch and Moddel<ref>{{US patent|7379286}}.</ref> details a device that is able to extract power from zero-point fluctuations using a gas that circulates through a Casimir cavity. A published test of this concept by Moddel<ref>{{cite journal|last1=Dmitriyevaa|first1=Olga|last2=Moddel|first2=Garret|title=Test of zero-point energy emission from gases flowing through Casimir cavities|journal=Physics Procedia|date=2012|volume=38|pages=8–17|doi=10.1016/j.phpro.2012.08.007|url=http://ecee.colorado.edu/~moddel/QEL/Papers/DmitriyevaModdel12.pdf|bibcode=2012PhPro..38....8D|access-date=1 November 2016|archive-date=7 May 2021|archive-url=https://web.archive.org/web/20210507132503/https://ecee.colorado.edu/~moddel/QEL/Papers/DmitriyevaModdel12.pdf|url-status=dead}}</ref> was performed in 2012 and seemed to give excess energy that could not be attributed to another source. However it has not been conclusively shown to be from zero-point energy and the theory requires further investigation.<ref>{{cite thesis|type=Thesis for: MS|last1=Henriques|first1=Carlos|others=Advisors: Fernandes, Luis & Amaro, F.|title=Study of atomic energy shifts induced by Casimir cavities|date=2014|doi=10.13140/RG.2.1.4297.1608}}</ref>