When a particle undergoes quantum tunneling, the wave function does not collapse in the conventional sense. Quantum tunneling is a phenomenon in quantum mechanics where a particle can pass through a potential barrier even though its energy is lower than the barrier height. This behavior is described by the wave nature of particles and the wave function associated with the particle.
In quantum mechanics, the wave function describes the probabilistic distribution of a particle's properties, such as its position or momentum. When a particle encounters a potential barrier, its wave function extends both before and after the barrier. The wave function represents the superposition of possible states, including states on both sides of the barrier.
During quantum tunneling, the particle's wave function penetrates the barrier, allowing the particle to be detected on the other side with a finite probability. However, the wave function does not fully collapse into a single definitive state during this process. Instead, it evolves and interferes with itself, leading to the probability distribution of the particle being spread out both before and after the barrier.
Only when a measurement is made on the particle, such as detecting its position or momentum, does the wave function collapse into a definite state associated with the measured value. Quantum tunneling itself is not a measurement process but rather a behavior governed by the wave-like nature of particles described by the Schrödinger equation.
So, to summarize, the wave function does not collapse during quantum tunneling itself. Instead, the wave function undergoes evolution and interference, allowing the particle to exhibit wave-like behavior by passing through the potential barrier.