A newly-discovered fundamental property of electrical currents in extremely small metal circuits demonstrates how negatively-charged particles can wash over said circuit like waves, generating interference in parts of the circuit where no current is delivered.
This characteristic, discovered by researchers at the University of Twente’s MESA+ institute and detailed in a recent Scientific Reports paper, is due largely to the circuit’s geometry as well as the quantum mechanical wave character of electrons, according to the study authors.
As part of their research, the MESA+ team demonstrated electron interference—a phenomenon in which propagating waves interact coherently—in a gold ring with a 500 nanometer diameter. One side of the ring was connected to a tiny wire through which an electrical current could be driven, while the other side was connected to a different wire attached to a voltmeter.
When they applied the current, sending a varying magnetic field through the ring, they detected electron interference on the other side of the ring, even though no net current passed through the ring. Their experiment revealed that electrons can bleed into the ring, thus altering the electrical properties in parts of circuit not expected to be affected by the current.
Findings could help shape future quantum computers
Despite the fact that the gold ring was diffusive (its electron mean free path was much smaller than the ring itself), the authors said that the effect was surprisingly pronounced. It shows that electrons must be considered waves in nanoscale circuits at extremely low temperatures, since this behavior is said to be a prime example of quantum mechanical wave-particle duality.
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