Quantum Physics Contradicts the Second Law of Thermodynamics


In the current issue of Foundations of Physics, we present a Gedankenexperiment that reveals a highly surprising, fundamental inconsistency between quantum theory and thermodynamics.

This photonic experiment, which can be performed in a practical manner, comprises two black bodies coupled by two chiral waveguides to a set of two-level systems that absorb and emit radiation. Our experiment combines coherent propagation of photons with random absorption and emission. We show that this combination forces an isolated thermodynamic system that is in standard thermodynamic equilibrium to reduce its total entropy. The Gedankenexperiment thereby demonstrates that the foundations of quantum physics, coherence and probabilistic events, contradict the second law of thermodynamics!

For movie buffs – as we have placed the manuscript on arXiv already in 2018, we have beaten Hollywood by two years! [tenet trailer]. 
For electronic freaks: the idea also works in electronic devices: arXiv:1912.11948.


Fig. 1: Sketch illustrating in simple terms photons being absorbed in a probabilistic process (“quantum jump”) and later reemitted by spontaneous emission. An atom anchored in a crystal lattice may absorb a photon impinging on it from any direction, as long as the incoming mode has finite overlap with the dipole mode of the TLS. The excited atom later relaxes by emitting a photon as an outgoing spherical wave with arbitrary polarization, independent of the direction or polarization of the previously absorbed photon ((a) and (b)).
Fig. 2: Temporal development of the total entropy for a closed variant of our system, shown in the inset. The initial state (thermal equilibrium between all subsystems, including the waveguide) maximizes the entropy. The stable steady state for long times has a lower entropy.


Inconsistency between Thermodynamics and Probabilistic Quantum Processes, D. Braak and J. Mannhart,
arXiv:1811.02983 (2018)


Closely related articles are available here:

Lossless Currents at High Temperatures, J. Mannhart and D. Braak,
Journal of Superconductivity and Novel Magnetism 31, 17-21 (2018)

Non-reciprocal Interferometers for Matter Waves, J. Mannhart,
Journal of Superconductivity and Novel Magnetism 31, 1649–1657 (2018)

Phase Filters for a Novel Kind of Asymmetric Transport, J. Mannhart, P. Bredol, and D. Braak,
Physica E: Low-dimensional Systems and Nanostructures 109, 198-200 (2019)


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