Yes, particles can indeed quantum tunnel through physical barriers, a phenomenon known as quantum tunneling. It is a fundamental concept in quantum mechanics and has been experimentally verified.
In classical physics, particles are expected to be confined within certain energy levels and unable to pass through energy barriers higher than their own energy. However, in quantum mechanics, particles can exhibit wave-particle duality, meaning they can behave as both particles and waves. This duality allows particles to "tunnel" through energy barriers that would be classically impenetrable.
Quantum tunneling occurs because of the probabilistic nature of quantum mechanics. According to the wave function of a particle, there is a finite probability of finding the particle in regions that are classically forbidden. When a particle encounters a barrier with energy higher than its own, there is a non-zero probability that it can tunnel through the barrier and appear on the other side.
Experimental verification of quantum tunneling has been carried out using various methods. One common approach involves studying the behavior of particles at the nanoscale. For example, scanning tunneling microscopy (STM) and atomic force microscopy (AFM) are techniques that utilize quantum tunneling to probe the surface of materials at the atomic level.
In STM, a sharp conducting tip is brought very close to the surface of a sample, and a bias voltage is applied between them. Due to quantum tunneling, electrons can flow between the tip and the surface, resulting in a measurable tunneling current. By mapping the variations in this current, researchers can create high-resolution images of the surface.
Another example is the tunneling effect in semiconductor devices, such as the scanning tunneling transistor microscope (STTM). This device exploits quantum tunneling to control the flow of current between two closely spaced electrodes, enabling precise measurements and manipulation of individual electrons.
These experimental techniques, among others, provide evidence for the existence of quantum tunneling. They demonstrate that particles can indeed traverse physical barriers, despite not possessing sufficient classical energy to overcome them.
It's worth noting that while quantum tunneling is a well-established phenomenon, it occurs on very small scales and is not typically observed in everyday macroscopic objects. Its effects become more prominent in the microscopic and nanoscopic realm, where quantum mechanics dominates classical physics.