Physics World (Nanomaterials)

Extracting Entropy Information From Quantum Dots

Stanford researchers have directly measured entropy production in semiconductor quantum dots, providing a quantitative view of energy dissipation at the nanoscale. By continuously exciting the dots with ultraviolet light and toggling a strong laser, they induced non‑equilibrium blinking and captured fluorescence traces. Machine‑learning‑optimized hidden Markov models reconstructed hidden state trajectories, allowing precise entropy calculations. Published in Nature Physics, the work moves beyond ideal two‑state systems to real materials with memory effects, offering a new metric for device efficiency limits.