Microscopic Quantum Heat Engine That Outperforms Classical Engines

Researchers have used an ensemble of NV− centers in diamond for implementing different types of quantum heat engines. They have used these to demonstrate the equivalence of the power output of two different engine types, continuous and two-stroke, for small actions. Additionally, they have shown that, for very small actions, the engines produce more power than their classical counterparts, significantly exceeding the stochastic power bound. These measurements constitute the first observation of quantum thermodynamic effects in heat machines.

They hope that this work will motivate further research along at least three lines:

1) Demonstration of quantum effects in other physical realisations of heat machines such as superconducting circuits and ion traps.
2) Theoretical search of quantum thermal signatures in heat machines based on other quantum agents such as entanglement and quantum discord.

3) Application to the design and development of novel devices such as room-temperature masers. They further hope that this work will be of
interest to other research areas concerned with the role of quantum coherence in the enhancement of work extraction by microscopic heat engines, such as the study of photosynthesis and the
development of solar cells.

Physical Review Letters – Experimental Demonstration of Quantum Effects in the Operation of Microscopic Heat Engines

SOURCE -Arxiv, Physical Review Letters

By Brian Wang, Nextbigfuture.com

6 thoughts on “Microscopic Quantum Heat Engine That Outperforms Classical Engines”

  1. Classical heat engines cannot reach the Carnot limit let alone exceed it.

    P.S. I read the paper, that’s how I know

  2. Not my area of experitise, (if any) but I was under the impression that thermodynamics was, at heart, a statistical phenomena. It does not apply to individual atoms, but only to large numbers of atoms that together form a gas, or liquid or something.

    One can point to cases where individual atoms apparently break thermodynamics. eg. Heat will never flow from a cooler object to a warmer object. But at an atomic level the temperature of a substance is the average temperature of all the atoms. Atoms, especially in a fluid, have a range of individual thermal energies, which is “impossible” if heat would always flow from the hot atoms to the cool atoms.
    Which is why evaporation works. Individual atoms can randomly accumulate enough thermal energy to break off from a liquid and become a gas, leaving the rest of the liquid behind. That just can’t happen on a macroscopic scale, you’ll never have a brick wall and one of the bricks randomly accumulate enough thermal vibrations from the thermal energy of all the others to suddenly melt. (For which I am daily thankful.)

    Anyway it is therefore not beyond the realms of possibility for a “heat engine” running on a “working fluid” of only one or a few atoms to thereby be able to get better efficiency than a carnot engine.

    What is not possible is to link all those engines together to produce a macroscopic better than carnot machine. Something about linking them all together is bound to introduce mass statistical behaviour and…oops

  3. The Carnot cycle isn’t a classical heat engine? Maybe “classical heat engines” does not mean what I thought it did.

  4. So, when will I be able to link a mole of these together, connect the hot end to my wood fired furnace, the cold end to my hot water tank, and kiss my power bill goodbye? I wanna co-generate already, but my heating load is too small in the summer for crappy Carnot level thermal efficiency!!!

    On a serious note, is it really a heat engine if it violates the second law of thermodynamics, which states the change of entropy of a closed system with time is never less than zero? That’s what’s happening if Carnot’s Theorem is being violated. In honor of James Clerk Maxwell, I proclaim this device to be “The Demon”. Let the freaking out by thermodynamicly illiterate evangelicals begin!

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