Thermodynamic Cost of Quantum Coherence in Photosynthetic Energy Transfer
Dhiraj Kumar, Niraj Kumar
Quantum coherence in biological systems is often assumed to be thermodynamically expensive to maintain, but its actual energy cost has never been quantified. We compute the thermodynamic cost of quantum-coherent energy transfer in the FMO photosynthetic complex using Lindblad master equation simulations. At optimal ENAQT dephasing (γ = 100 cm⁻¹), the transport efficiency reaches 29.4%, the Holevo channel capacity peaks at 2.17 bits, and the Landauer ratio—the energy cost per successfully transmitted bit relative to the fundamental thermodynamic limit kT ln 2—is ~ 390×. This is approximately 104 times more efficient than classical CMOS computing (~ 107× Landauer). The entropy production rate peaks at 1.77 kB/ps at γ = 300 cm⁻¹, and the von Neumann entropy saturates at Smax = 2.45 bits at steady state. These results provide the first quantitative thermodynamic characterization of quantum-coherent energy transfer in a pigment-protein complex.
•Jul 22, 2026•0 citations