Electrons as Qubits: Not Perfect
Quantum bits, or qubits, are the units that will be the foundation of quantum computing. Unlike the binary system, wherein bits can only be either 1 or 0, qubits allow the superposition of each unit, meaning each bit can be both 0 and 1 at the same time. This creates exponentially superior computing power that allows calculations to be carried out with less steps than the classical system.
To learn more on the concept of qubits, watch the video below:
Researchers have been using individual electrons as qubits for the past years. An electron is locked in the quantum dot, which is a tiny semiconductor volume, and the spin turns it into a small permanent magnet. The direction of this spin is then used to code information.
The problem, however, is that atoms from its surroundings also generate magnetic fields—and this noise interferes with the external magnetic field and ultimately corrupts the process of programming and reading qubits.
A team of researchers from Ruhr-Universität Bochum, the University of Basel, and Lyon University have found a nifty solution to the hurdle: instead of using electrons as qubits, they used the “electron holes.”
Instead of locking individual electrons in the quantum dot, specific electrons were removed, leaving positively charged voids, or electron holes, that also have a spin but, unlike the electrons themselves, are immune from the interference caused by surrounding magnetic fields. “A hole spin may circumvent the nuclear spin noise. In principle, the nuclear spins can be switched off for a pure heavy-hole spin,” the study notes.
The downside, however, is that this can only be applied at low temperatures since these holes have a weakness to warmth. While the technique is still not perfect, it’s a step closer to making quantum computers a reality.