Eliran Assa

An international group of scientists sent higher-frequency sound waves across a modified semiconductor device to direct the behavior of a single electron, with efficiency above 99%.

3D render of the semiconductor nanostructure. Image credit: Hermann Edlbauer.

3D render of the semiconductor nanostructure. Image credit: Hermann Edlbauer.

A quantum pc would be capable to resolve previously unsolvable computational difficulties by taking benefit of the strange behavior of particles at the subatomic scale, and quantum phenomena such as entanglement and superposition.

Even so, precisely controlling the behavior of quantum particles is a mammoth process.

“What would make a quantum pc so effective is its potential to scale exponentially,” mentioned Hugo Lepage, a PhD candidate in the Cavendish Laboratory at the University of Cambridge.

“In a classical pc, to double the quantity of details you have to double the quantity of bits. But in a quantum pc, you’d only want to add a single additional quantum bit, or qubit, to double the details.”

Some styles of quantum computer systems are primarily based on superconducting loops, which are complicated circuits and, like all quantum systems, are very fragile.

“The smallest fluctuation or deviation will corrupt the quantum details contained in the phases and currents of the loops,” Lepage mentioned.

“This is nevertheless incredibly new technologies and expansion beyond the intermediate scale might call for us to go down to the single particle level.”

Rather of superconducting loops, the quantum details in the quantum pc Lepage and colleagues are devising use the ‘spin’ of an electron — its inherent angular momentum, which can be up or down — to shop quantum details.

“Harnessing spin to energy a functioning quantum pc is a additional scalable strategy than working with superconductivity, and we think that working with spin could lead to a quantum pc which is far additional robust, considering the fact that spin interactions are set by the laws of nature,” Lepage mentioned.

Employing spin makes it possible for the quantum details to be additional conveniently integrated with current systems.

The device created by the group is primarily based on extensively-applied semiconductors with some minor modifications and measures just a handful of millionths of a meter extended.

The researchers laid metallic gates more than a semiconductor and applied a voltage, which generated a complicated electric field.

They then directed higher-frequency sound waves more than the device, causing it to vibrate and distort, like a tiny earthquake.

As the sound waves propagate, they trap the electrons, pushing them by means of the device in a incredibly precise way, as if the electrons are ‘surfing’ on the sound waves.

Lepage and co-authors have been capable to handle the behavior of a single electron with 99.five% efficiency.

“To handle a single electron in this way is currently tricky, but to get to a point exactly where we can have a operating quantum pc, we want to be capable to handle several electrons, which get exponentially additional tricky as the qubits commence to interact with every other,” he mentioned.

The team’s perform is published in the journal Nature Communications.


Shintaro Takada et al. 2019. Sound-driven single-electron transfer in a circuit of coupled quantum rails. Nature Communications 10, post quantity: 4557 doi: 10.1038/s41467-019-12514-w

Eliran Assa