Fundamental limitations on photoisomerization from thermodynamic resource theories
Abstract
Small, outofequilibrium, and quantum systems defy simple thermodynamic expressions. Such systems are exemplified by molecular switches, which exchange heat with a bath. These molecules can photoisomerize, or change conformation, or switch, upon absorbing light. The photoisomerization probability depends on kinetic details that couple the molecule's energetics to its dissipation. Therefore, a simple, general, thermodynamicstyle bound on the photoisomerization probability seems out of reach. We derive such a bound using a resource theory. The resourcetheory framework is a set of mathematical tools, developed in quantum information theory, used to generalize thermodynamics to small and quantum settings. From this toolkit has been derived a generalization of the second law, the thermomajorization preorder. We use thermomajorization to upperbound the photoisomerization probability. Then, we compare the bound with an equilibrium prediction and with a Lindbladian model. We identify a realistic parameter regime in which the Lindbladian evolution saturates the thermomajorization bound. We also quantify the energy coherence in the electronic degree of freedom, and we argue that this coherence cannot promote photoisomerization. This work illustrates how quantuminformationtheoretic thermodynamics can elucidate complex quantum processes in nature, experiments, and synthetics.
 Publication:

arXiv eprints
 Pub Date:
 November 2018
 arXiv:
 arXiv:1811.06551
 Bibcode:
 2018arXiv181106551Y
 Keywords:

 Quantum Physics;
 Condensed Matter  Statistical Mechanics;
 Physics  Chemical Physics
 EPrint:
 8.5 pages. Published version