Simulating Single‐Particle Trajectories in a Double‐Slit Setup

To investigate whether classical elastic interactions between individual particles and double-slit boundaries can generate detection patterns resembling quantum interference fringes, without invoking intrinsic wave behaviour or measurement-induced effects.

The double‐slit experiment performed with individual particles has been reproduced many times, yet a universally accepted description of how a single particle can exhibit wave‐like behaviour remains elusive. In quantum mechanics we learn that any attempt to detect, observe, or measure a particle inevitably perturbs its trajectory, leading to conclusions that may not reflect the particle’s intrinsic dynamics. To explore the motion of a solitary particle without invoking measurement, we wrote a simple program that simulates its trajectory from a source (“the gun”) to a detection screen, allowing the particles to interact elastically with the interior surfaces of the slits. By systematically varying wall thickness, slit height, inter‐slit gap, particle speed, size, and incident angle, we generate a series of impact distributions ranging from uniform spreads to highly structured multi‐cluster patterns. Notably, when the wall thickness allows the particle to bounce several times inside the slit, the emergent patterns evolve into configurations that closely resemble the classic interference fringes of quantum double‐slit experiments. Our analysis reveals that these wave‐like imprints arise from the superposition of numerous classical trajectories produced by successive bounces off the slit walls, rather than from an intrinsic wave property of the particles. Consequently, the study suggests that apparent interference phenomena can be reproduced within a purely classical framework, highlighting the pivotal role of mechanical interactions between particles and slit boundaries in shaping observed detection patterns.

doubleslitexperimentquantumwaveparticledualityinterference