Engines and refrigerators have often been the subjects physicists have amused themselves with in the quest to calculate the properties of quantum machines. However, the primary question is how efficient and useful these devices actually are when the rules of classical mechanics are discarded for those of quantum mechanics. As physicists discover answers to this question, they are getting insights into the relationship between thermodynamics and quantum mechanics.
University of Gdansk Researcher, Robert Alicki, and Mark Fannes from the University of Leuven, are studying quantum batteries in order to better understand this conundrum. The question: when energy is stored temporarily how much work can be extracted from a quantum system?
Physicists have known about passive states for decades, so they want to expand their understanding to determine the difference between passive states and the energy of the quantum system. The resulting energy may then be extracted to apply elsewhere.
But the extractable work isn’t perfect because it is generally lower than the thermodynamic limit. However, physicists have discovered that the end result changes if several identical batteries are entangled, essentially sharing the same existence. The extraction from all batteries could then occur instantaneously. The thermodynamic limit is more closely reached as the number of entangled batteries increases, leading physicists to conclude the batteries are almost perfect.
The caveat: so far much of this work is theoretical. Practical limitations must be more accurately determined, and these determinations might change the actual end result. Only time, and additional research, will determine if quantum batteries truly are perfect.
[via MIT Technology Review]