Biexciton Binding Energy in a Quantum Dot

This simulator pumps a semiconductor quantum dot with electron-hole pairs and watches it cycle through empty, single-exciton (X) and biexciton (XX) states, each recombination releasing a photon into a live, accumulating photoluminescence spectrum. The separation between the X and XX peaks is the biexciton binding energy ΔXX — a real many-body effect where direct Coulomb attraction competes with exchange and correlation repulsion between the two confined electron-hole pairs. Shrink the dot and the balance of that competition flips: the XX line crosses from redshifted (bound) to blueshifted (antibound) of twice the exciton energy, exactly the sign-changing behavior measured in real colloidal quantum dot spectroscopy. Temperature broadens the lines by phonon dephasing, and a correlation-strength slider lets you explore how a stronger many-body interaction shifts where that sign flip happens.