Yes, quantum tunneling is a well-established phenomenon in quantum mechanics that has been experimentally observed and confirmed. It is a phenomenon where a particle can pass through a barrier or potential energy barrier even when it does not have sufficient energy to overcome it according to classical physics.
Here are a few examples of quantum tunneling:
Alpha Decay: Alpha decay is a type of radioactive decay where an atomic nucleus emits an alpha particle (two protons and two neutrons). According to classical physics, the alpha particle would not have enough energy to overcome the strong nuclear force and escape the nucleus. However, quantum tunneling allows the alpha particle to penetrate the barrier and escape, resulting in the radioactive decay of the nucleus.
Scanning Tunneling Microscopy: Scanning Tunneling Microscopy (STM) is a technique used to image surfaces at the atomic level. It relies on the principle of quantum tunneling. A sharp conducting tip is brought close to the surface of a material, and a voltage is applied between the tip and the sample. Due to the quantum tunneling effect, electrons can tunnel through the vacuum gap between the tip and the surface, resulting in a measurable tunneling current. This current is used to create images of the surface topography with atomic resolution.
Field Emission: Field emission is a phenomenon where electrons can escape from the surface of a conductor into vacuum under the influence of a strong electric field. Quantum tunneling plays a crucial role in field emission because electrons can tunnel through the potential barrier created by the surface and escape into the vacuum region, despite lacking the classical energy required to overcome the barrier.
These are just a few examples of quantum tunneling, but the phenomenon has been observed and studied in various contexts, including quantum electronics, solid-state physics, nuclear physics, and more. It is a fundamental concept in quantum mechanics and has practical applications in a range of fields.