| Date | 29th, Dec 2020 |
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In one of the first practical applications of quantum effects to nanotechnology, researchers from RIKEN have recently developed a quantum nanodevice that can simultaneously act as a heat engine and a refrigerator.
Currently existing heat engines and refrigerators are based on the same principle, yet perform opposite functions. Both rely on connecting two pools of fluid – compressing one pool causes its fluid to heat up, while rapidly expanding the other does the opposite. Alternating both in a periodic cycle will make the system function as either a heat engine or a fridge.
Fridge or heat engine? Why not both! Exploiting quantum properties could allow engineers to build counterintuitive, yet tremendously powerful technologies in the future. This image does not illustrate the actual research. Image: Thor Deichmann via pixabay.com, Pixabay License
According to Keiji Ono from the RIKEN Advanced Device Laboratory, building a machine capable of simultaneously performing both operations at macroscale is not only impossible, but also undesirable. “Combining a traditional heat engine with a refrigerator would make it a completely useless machine. It wouldn’t know what to do.”
The new device employs a transistor that contains an electron with two possible energy states. To increase the gap between them, Ono and colleagues applied an electric field and microwaves, resulting in a process reminiscent of the periodic expansion-compression of a fluid housed within a chamber.
First, the research team demonstrated that the nanodevice is capable of acting as either a heat engine or a refrigerator by monitoring the occupancy of the upper energy level – a neat, but unsurprising result given the underlying dynamics of the system.
Next, the team showed that it can also perform both functions at the same time. The feat was confirmed by again looking at the occupancy of the upper energy level, which combined to create an interference pattern that perfectly matched the team’s predictions based on quantum theory.
Ono was positive that his team’s findings could make a real-world contribution to the field of nanotechnology. “This may allow rapid switching between the two modes of operation. This ability could help create novel applications with such systems in the future.”
A paper detailing the research was published in the journal Physical Review Letters.
Source: riken.jp
