On the centennial of modern quantum mechanics, the Nobel Committee awarded the year’s most prestigious physics prize to an experiment that demonstrated how quantum effects play out on large scales—including inside your smartphone.
In fact, the implications of this year’s winner—quantum tunneling—stretch way beyond the device in your pocket.
John Clarke, Michel Devoret, and John Martinis conducted their initial experiments in 1984 and 1985, but their work has had a lasting impact, becoming “the foundation of all digital technology,” Olle Eriksson, Chair of the Nobel Committee for Physics, said in a statement.
But what is quantum tunneling, and how has it brought this bizarre realm of physics into our everyday devices? Read on to discover why this quirk of quantum is so critical.
Quantum tunneling, the basics
Imagine throwing a tennis ball against a wall. Millennia of both scientific and anecdotal observations teach that the ball will likely hit the wall and bounce back. In the quantum world, however, that isn’t always the case. There, the ball might pass straight through the wall and appear on the other side—a phenomenon referred to as “tunneling.”
Size is a tricky concept in quantum mechanics, but very simply speaking, “microscopic” scales in this context generally refer to that of a single particle. By contrast, “macroscopic” refers to a large number of particles. Quantum mechanical effects appear to fade on the macroscopic scale, hence why a tennis ball—comprised of a gazillion particles—typically doesn’t pass through walls.
But the Nobel-winning experiment created a highly sophisticated, superconducting circuit that enabled electrons inside to move through the system as if they were a single particle, filling the entire circuit. The electrons in the system tunneled through a thin layer of non-conductive material—and thus, the circuit, which the researchers had described as being “big enough to get one’s grubby fingers on,” is a macroscopic demonstration of a microscopic, or quantum, phenomenon.
The quantum in your smartphone
To be clear, superconducting devices aren’t here yet. But the chip in your phone, while being a semiconductor, not a superconductor, still utilizes the lessons from the tunneling experiment to work. As do transistors, nuclear experiments, and, of course, quantum computing.
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