Future quantum computers could use bizarre 'error-free' qubit design built on forgotten research from the 1990s

Quantum bits, or qubits, made from electrons floating on top of liquid helium could one day power the next generation of quantum computers, according to a new study.

While the bits that power classical computers encode data as either 0 or 1, qubits can be a superposition of these two states — meaning they can occupy both in parallel while processing calculations. Computers built this way can one day be much more powerful than today’s fastest supercomputers — and promise to be transformative in several fields including drug discovery and tackling climate change.

Qubits are normally made by manipulating the spin state of an electron between its spin-up and spin-down positions, which represent 1 and 0. 

Other particles used as qubits include trapped ions, photons, artificial or real atoms and quasiparticles, according to Microsoft, and most qubits achieve a superposition by cooling a superconducting metal (which contains the particle) to absolute zero.

But in a study published Nov. 9 in the journal Physical Review Applied, scientists argue this conventional approach to building a qubit is challenging. That's because combining electrons and solid-state crystals (including metals) creates impurities in the material. This means qubits aren't uniform and, in turn, this leads to a higher chance of qubits failing during calculations.

Related: How could this new type of room-temperature qubit usher in the next phase of quantum computing?

These defects can cause several issues, including  “unpredictable electrical potential” and difficulty producing “many uniform qubits,” the scientists said in a statement. It also means that scaling up the number of qubits in a quantum system will amplify the error rate.