Quantum tunneling is a phenomenon in quantum mechanics where a particle can pass through a potential barrier even though it does not have enough energy to overcome that barrier according to classical physics. While we cannot directly "observe" quantum tunneling in the same way we observe macroscopic objects, there are experimental techniques that allow us to indirectly detect its effects.
In the case of observing quantum tunneling at the atomic level, it is not possible to directly observe the atom as it tunnels through a barrier in real-time using a traditional microscope. This is because the scale at which quantum tunneling occurs is far smaller than the resolution of optical microscopes.
However, there are indirect ways to study and infer the occurrence of quantum tunneling. For example, scanning tunneling microscopes (STMs) and similar techniques can provide images and measurements of atomic and molecular structures on surfaces. These techniques rely on the quantum mechanical phenomenon of electron tunneling, which is conceptually related to particle tunneling.
Additionally, experiments involving quantum systems, such as electron tunneling through a potential barrier, can provide evidence for the existence of quantum tunneling. These experiments can measure the probabilities of particles appearing on the other side of the barrier, even when their energy is insufficient according to classical physics.
In summary, while we cannot directly observe an atom tunneling through a barrier with a traditional microscope, there are experimental methods that allow us to indirectly detect and study the effects of quantum tunneling at the atomic level.