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takyon [soylentnews.org] writes:

Quantum Correlations Reverse Thermodynamic Arrow of Time [quantamagazine.org]

A team of physicists has made heat flow spontaneously [arxiv.org] from a cold quantum object to a hot one. The experiment underscores the intimate relationships between information, entropy and energy that are being explored in the nascent field of quantum thermodynamics [quantamagazine.org].

The team, based in Brazil, took a molecule that consisted of a carbon atom, a hydrogen atom and three chlorine atoms. They then generated a magnetic field to align the nuclear spins of the two quantum particles, or "qubits" — the carbon and hydrogen nuclei. This caused the nuclei to become linked, or correlated, turning them into a single, inseparable whole, a two-qubit quantum state.

[...] If the total entropy suddenly decreased in a regular, uncorrelated system, it would violate the second law. But here, the researchers take the correlation into account. The weakening of the correlation is akin to a "fuel driving the heat from the colder to the hotter body," said David Jennings [imperial.ac.uk], a physicist at Imperial College London. The cold qubit gets colder, the hot qubit hotter. In other words, heat flows from cold to hot. This occurs because of "a trade-off between correlations and entropy," said Roberto Serra [rmserra.org], a physicist at the Federal University of ABC and the head of the research group behind the study.

The operation effectively reverses the arrow of time, at least in this isolated system. "The thermodynamic arrow of time relies on the notion that the entropy of a closed system can only increase or remain constant, but never decrease," Micadei said. "By creating in the lab an isolated system where the entropy decreases, in the system the arrow of time should point to the opposite direction."

Also at Oregon Public Broadcasting [opb.org], which bravely names the molecule [wikipedia.org].

Original Submission