We can now forget about ever trying to reach absolute zero

23 Mar 2017

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Some ‘cool’ new research conducted by a team of physicists has proven once and for all that it is impossible for us to cool something to absolute zero.

Pushing the laws of nature to its physical limit is something that scientists are quite familiar with, but one thing that has apparently remained completely out of reach is hitting the point of absolute zero.

At minus 273.15 degrees Celsius, absolute zero is the theoretical temperature that nothing can surpass in coldness, even the vacuum of space, which is still a chilly minus 270.5 degrees Celsius.

Attempts to reach absolute zero have come close to the target, with organisations such as NASA reaching within a billionth of a degree.

Now, a team of physicists from the University College of London has proven for the first time that any future attempts at trying to reach it will end in failure, because it is scientifically and physically impossible.

According to Phys.org, the researchers have proven a 105-year-old theory proposed by chemist Walther Nernst, who said that cooling an object to absolute zero is impossible with a finite amount of time and resources.

Known as the unattainability principle, it is the most commonly accepted version of the third law of thermodynamics and now it is cemented as scientific fact.

To help prove Nernst’s theory, physicists Lluís Masanes and Jonathan Oppenheim used quantum information theory – a familiar idea to computer scientists – to see how much work and resources would be necessary to reach absolute zero.

Quantum computer research

After running some calculations, it became evident that the amount of energy needed to do this would have to be infinite, as a state of zero entropy is not possible with finite resources.

This isn’t to say, however, that ultra-low temperatures close to absolute zero cannot be achieved, the pair added.

“In addition, this derivation unveils the strong connections among the limitations of cooling, the positivity of the heat capacity, the reversibility of microscopic dynamics etc,” said Masanes.

“Personally, I love that the whole of thermodynamics (including the third law) has been derived from more fundamental principles.”

The implications for their findings – now published in Nature Communications ­– could have major implications for advanced research in quantum computers and highly precise measurements.

Masanes added: “Now that we have a better understanding of the limitations of cooling, I would like to optimise the existing cooling methods, or come up with new ones.”

Colm Gorey was a senior journalist with Silicon Republic