New Research Brings Us One Step Closer to a Functioning Quantum Computer

The researchers demonstrated the switching of electron states across an array of qubits.
Chris Young

Scientists at Purdue University and the University of Rochester have demonstrated a method of relaying information by transferring the state of electrons.

The researchers claim this brings us one step closer to creating a fully functioning quantum computer.

This is part of the University of Rochester's ongoing work in quantum systems, after having received a $4 million grant from the Department of Energy to explore quantum materials.


Computing of the future

Quantum computing could lead the way for much faster database searchers and cryptography. It should be able to carry out processes that are beyond the realms of classical computing.

Researchers including John Nichol, an assistant professor of physics, and Rochester Ph.D. students, Yadav P. Kandel and Haifeng Qiao have been pushing for progress in the field. 

An important, but a tricky component to control in quantum computing is the switching state of electrons.

"If you have one electron that's up and another electron that's down and you push them together for just the right amount of time, they will swap," Nichol said in a press release.

"They did not switch places, but their states switched."

New Research Brings Us One Step Closer to a Functioning Quantum Computer
Source: University of Rochester/J. Adam Fenster

State switching

In order to manually make this phenomenon happen, Nichol and his colleagues cooled down a semiconductor chip to extremely low temperatures.

They, then, used quantum dots — nanoscale semiconductors — and trapped four electrons in a row, after which they moved the electrons so they touched and their states switched.

"There's an easy way to switch the state between two neighboring electrons, but doing it over long distances—in our case, it's four electrons—requires a lot of control and technical skill," Nichol said.

"Our research shows this is now a viable approach to send information over long distances."

A big step on a long road

Changing the state of an electron back and forth across a series of qubits — the bit equivalent for quantum computing — without moving the position of electrons is an impressive display of the potential of quantum physics for computing.

"This experiment demonstrates that information in quantum states can be transferred without actually transferring the individual electron spins down the chain," Michael Manfra, a professor of physics and astronomy at Purdue University, said in the press release.

"It is an important step for showing how information can be transmitted quantum-mechanically—in manners quite different than our classical intuition would lead us to believe."

Nichol compares this experiment to the leadup from the first computer devices to the computers of today, while stressing that we are still very much in the early stages of quantum systems.

Could we one day have quantum computing laptops? "If you had asked that question of IBM in the 1960s, they probably would've said no, there's no way that's going to happen," Nichol says.