(Forbes.com) Quantum tunneling serves as the basis for Scanning Tunneling Microscopy (STM), which uses the tunneling of electrons across a tiny gap between a sharp tip and a surface to produce maps of that surface that can readily resolve single atoms. STM works by scanning a very sharp metal wire tip over a surface. By bringing the tip very close to the surface, and by applying an electrical voltage to the tip or sample, we can image the surface at an extremely small scale – down to resolving individual atoms
It’s also essential for the Josephson effect, which is the basis of superconducting detectors of magnetic fields and some of the superconducting systems proposed for quantum computing.
There is an ongoing debate and research over how long does quantum tunneling take?” The tricky part is that the distances involved in quantum tunneling are necessarily very small, making the times involved extremely short. The latest contribution to the ongoing argument is in the form of a new tunneling-time paper from Aephraim Steinberg’s group at the University of Toronto. This one uses the internal states of atoms tunneling through a barrier to make a kind of clock that only “ticks” while the atoms are inside the barrier region.

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