Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties submitted time 2017-01-23
Abstract：In this note, we point out that a case of mechano-caloric effect of superfluid $^4$He actually establishes a temporary entropy-decreasing process, which was unnoticed in the past. We show that this process can be used to convert thermal energy from the environment to useful energy in principle, and therefore, the second law of thermodynamics is not an universal law.
Peer Review Status:
Awaiting Review
Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties submitted time 2017-01-10
Abstract：We argue microscopically that helium-4 superflows carry heat unavoidably. We then show that a heterogeneous helium-4 superflow loop can be used to realize an entropy-decreasing process, thus providing an exception to the second law of thermodynamics. This exception is a quantum effect for its essential dependence on the quantum phenomenon of superfluidity.
Peer Review Status:Awaiting Review
Subjects: Physics >> Condensed Matter: Electronic Structure, Electrical, Magnetic, and Optical Properties submitted time 2016-09-21
Abstract：We review on a recently proposed quantum exception to the second law of thermodynamics. We emphase that helium-4 superflows, like any other forms of flows, shall carry entropy or heat in a thermal environment. Following that, one can use a heterogeneous helium-4 superflow loop to realize entropy-decreasing processes. We also mention that the heat content of a superflow has an unusual dependence on flow velocity, which is an important factor contributing to the entropy-decreasing processes.
Peer Review Status:Awaiting Review
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