New theory links quantum light engines to usable energy beyond waste heat
Physicists at the University of Basel have devised a framework that reconciles quantum mechanics with thermodynamics for tiny light-driven engines, showing that some emitted photons can still perform work.
Scientists at the University of Basel presented a mathematical framework that unifies quantum physics and thermodynamics for microscopic engines composed of a single atom and photons. The model features an atom placed in a cavity between two mirrors, with a laser supplying photons and some light escaping through partially reflective surfaces, creating a driven-dissipative system. By treating the atom quantum mechanically and the light classically, the researchers identified which portion of the emitted energy qualifies as useful work versus disordered heat, ensuring a consistent semi-classical limit.
Their analysis shows that labeling all escaping photons as waste heat leads to inconsistencies, whereas recognizing a usable fraction yields a coherent description. Additionally, the study reveals that quantum effects can reduce fluctuations in the emitted light, a trait valuable for quantum metrology and other emerging technologies. The work was published in Physical Review Letters.
Why it matters
Understanding how to harvest usable energy from quantum systems could boost efficiency of future quantum technologies.
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