Phys.org March 5, 2021 The classical Gibbs paradox concerns the entropy change upon mixing two gases. Whether an observer assigns an entropy increase to the process depends on their ability to distinguish the gases. Moving the thought experiment into the quantum realm researchers in the UK have shown that the ignorant observer can extract work from mixing different gases, even if the gases cannot be directly distinguished. In the macroscopic limit, the quantum case diverges from the classical ideal gas: as much work can be extracted as if the gases were fully distinguishable. They showed that the ignorant observer assigns […]
Tag Archives: Quantum heat engine
New quantum nanodevice can simultaneously act as a heat engine and a refrigerator
Phys.org December 28, 2020 An international team of researchers (Japan, Ukraine, USA – University of Michigan) has experimentally demonstrated the quantum version of the heat engine which uses an electron in a transistor. The electron has two possible energy states. The team could increase or decrease the gap between these energy states by applying an electric field and microwaves. This can be analogous to the periodic expanding–compressing operation of a fluid in a chamber. The device also emitted microwaves when the electron went from the high-energy level to the lower one. By monitoring whether the upper energy level was occupied, […]
The experimental demonstration of a spin quantum heat engine
Phys.org December 30, 2019 An international team of researchers (Canada, Singapore, Brazil) successfully demonstrated that the proof-of-concept quantum heat engine is able to reach an efficiency for work extraction very close to its thermodynamic limit. They used a nuclear spin placed in a chloroform molecule and nuclear magnetic resonance techniques. They specifically manipulated the nuclear spin of a Carbon 13 isotope using a radiofrequency field, ultimately producing an Otto cycle (i.e., the thermodynamic cycle used in most common motors). They were able to characterize all energy fluctuations in work and heat, besides the irreversibility at the quantum scale…read more. TECHNICAL […]