The double-slit experiment is a fundamental experiment in quantum physics that demonstrates the wave-particle duality of matter and the probabilistic nature of quantum mechanics. It involves shining a beam of particles, such as electrons or photons (particles of light), at a barrier with two closely spaced slits. The particles then pass through the slits and create an interference pattern on a screen placed behind the barrier.
When the particles are observed or measured, they behave like discrete particles and produce a pattern that resembles two distinct bands corresponding to the positions of the two slits. However, when the particles are not observed, they exhibit wave-like behavior and produce an interference pattern consisting of alternating light and dark bands, similar to the pattern created by overlapping waves.
This experiment illustrates the wave-particle duality, which suggests that particles like electrons and photons can exhibit both particle-like and wave-like characteristics. The particles behave as waves when they are not observed or measured, and their behavior becomes localized and particle-like when an observation is made.
As for whether the double-slit experiment can be done with objects other than particles, such as macroscopic objects, it becomes increasingly challenging due to various factors. The main challenge lies in maintaining the coherence of the wave-like behavior of larger objects, which is necessary for the interference pattern to be observed. The wave-like behavior tends to rapidly decohere and interact with the environment, making it difficult to observe the interference pattern.
While there have been some attempts to extend the experiment to larger objects, such as molecules or even buckyballs (a form of carbon), the success has been limited. These experiments face significant technical challenges and require carefully controlled environments to minimize decoherence. So, while the double-slit experiment has been extensively studied and demonstrated with particles like electrons and photons, extending it to macroscopic objects remains a significant challenge in experimental physics.