The behavior of wave functions and their collapse is a fundamental aspect of quantum mechanics, which is a well-established and extensively tested theory in physics. While it is true that the act of measurement or observation can cause the collapse of a wave function, scientists can still infer the existence of wave functions through various experimental and theoretical investigations.
One of the key pieces of evidence for the existence of wave functions comes from the phenomenon of interference. Interference patterns, such as those observed in the famous double-slit experiment, demonstrate the wave-like nature of particles and their associated wave functions. These patterns arise from the superposition of multiple possible states of a particle interfering with each other, which can only be explained through the concept of wave functions.
Additionally, the predictions of quantum mechanics, based on the mathematical framework of wave functions, have been extensively verified through experiments. Quantum mechanics has provided remarkably accurate predictions of various physical phenomena, including atomic and molecular spectra, electron behavior, and the behavior of particles in accelerators. These predictions have been repeatedly confirmed by experimental results, lending strong support to the existence and utility of wave functions.
It's important to note that the collapse of a wave function upon observation is not fully understood and remains a topic of interpretation and debate within the field of quantum mechanics. There are different interpretations, such as the Copenhagen interpretation, which suggests that the act of measurement causes the collapse, and other interpretations like the many-worlds interpretation or the pilot-wave theory that propose alternative explanations.
While the exact nature of wave function collapse is still an active area of research and discussion, the existence and behavior of wave functions have been confirmed through a wide range of experiments and their successful application in understanding and predicting the behavior of particles at the quantum level.