Yes, there is abundant experimental evidence supporting the existence of quantum tunneling. Quantum tunneling is a phenomenon where a particle can pass through a potential barrier even if it does not possess enough energy to overcome it classically.
One of the earliest and most famous demonstrations of quantum tunneling is the alpha decay of radioactive nuclei. In alpha decay, an unstable atomic nucleus emits an alpha particle (consisting of two protons and two neutrons) to become a more stable nucleus. According to classical physics, the energy possessed by the alpha particle is not sufficient to overcome the strong nuclear forces holding the nucleus together. However, quantum tunneling allows the alpha particle to penetrate the potential barrier and escape from the nucleus.
Experimental observations of alpha decay rates and the energy spectra of the emitted alpha particles provide strong evidence for quantum tunneling. These measurements consistently match the predictions made by quantum mechanical models, confirming the validity of the phenomenon.
Quantum tunneling is also observed in various other areas of physics and technology. For example, scanning tunneling microscopy (STM) is a powerful technique used to image surfaces at the atomic scale. It relies on the tunneling of electrons between the microscope tip and the surface, providing detailed information about the surface topography and electronic structure.
In semiconductor devices, tunneling is exploited in tunnel diodes, where electrons can tunnel through a thin barrier, resulting in unique electrical properties. Similarly, tunneling is fundamental to the operation of flash memory, a common type of computer memory that stores information using quantum tunneling.
Overall, the experimental evidence for quantum tunneling spans multiple fields of physics, from nuclear decay to condensed matter physics and nanotechnology. The consistency between experimental observations and the predictions of quantum mechanics supports the reality of quantum tunneling as a fundamental quantum phenomenon.