SoylentNews is people
SoylentNews
Quantum Correlations Reverse Thermodynamic Arrow of Time
A team of physicists has made heat flow spontaneously 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.
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, 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, 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, which bravely names the molecule.
(Score: 0) by Anonymous Coward on Wednesday April 04 2018, @09:11PM (1 child)
That arrow of time bit is stupid, we fundamentally don't quite understand what time is, but it sure as hell isn't dependent on energy being creatively shuffled from one object to another.
Now whether the entropy of the system was actually decreased depends on how much entropy was created by the magnetic field.
(Score: 0) by Anonymous Coward on Thursday April 05 2018, @09:38AM
Time is spatial dimension in the axis of your light-speed movement. See relativity.
Our notion of "passage of time" is actually a memory, a history if you will. For systems which can't collect history, time is not a thing.
And regarding increase of entropy as definition of time arrow, unless there is dispersion of energy involved, it is just a matter of observer's choice which state is considered "ordered", and the more the system is distant in time from that state, the greater entropy will be, regardless of the direction of time flow.