Kaksireikäkoe

The kaksireikäkoe, or double-slit experiment, is a fundamental experiment in quantum mechanics that demonstrates the wave-particle duality of light and matter. In its simplest form, the experiment involves firing particles, such as photons or electrons, at a barrier with two narrow slits. Behind the barrier, a detector screen records where the particles land.

If the particles behaved solely as classical particles, one would expect to see two distinct bands on the detector screen, corresponding to particles passing through each of the slits. However, the results show a different pattern. Instead of two bands, an interference pattern emerges, characterized by alternating bright and dark fringes. This pattern is characteristic of waves interfering with each other.

The interference pattern suggests that each particle, when unobserved, passes through both slits simultaneously and interferes with itself, acting like a wave. However, if a detector is placed at the slits to observe which slit each particle passes through, the interference pattern disappears, and the particles behave like classical particles, forming two distinct bands on the screen. This phenomenon, known as wave function collapse, implies that the act of observation influences the behavior of quantum entities. The kaksireikäkoe has profound implications for our understanding of reality at the quantum level, challenging classical intuition and forming a cornerstone of quantum physics.