Australian Researchers lead by a group at the University of New South Wales have been able to construct a quantum computing setup where two qubits were able to "communicate" with each other for the first time. This is an important breakthrough in the construction of fully functioning quantum computers.
As reported in Nature Communication, this is the first time that scientists have been able to control interactions between two of these qubits. But this is not the only success for the team. They also created quantum circuits with the lowest noise and even hold the record for the longest stable qubit – 30 seconds.
The research group's aim is to build a silicon quantum computer atom by precisely positioned atom. With this approach, they hope to deliver a completely scalable quantum device.
“The combined results from these three research papers confirm the extremely promising prospects for building multi-qubit systems using our atom qubits,” senior author Scientia Professor Michelle Simmons, said in a statement.
“Our competitive advantage is that we can put our high-quality qubit where we want it in the chip, see what we’ve made, and then measure how it behaves. We can add another qubit nearby and see how the two wave functions interact. And then we can start to generate replicas of the devices we have created.”
The team placed three phosphorus atoms inside a silicon chip. Two atoms made up one qubit and the remaining made up the other. The chip had electrodes patterned into it that allowed the team to control the interactions between the neighboring qubits. The team made sure that the atoms' spin became correlated so when one was pointing up the other was pointing down, and vice versa.
“These type of spin correlations are the precursor to the entangled states that are necessary for a quantum computer to function and carry out complex calculations,” co-author, Dr Matthew Broome, formerly of UNSW and now at the University of Copenhagen, added. "This is a major milestone for the technology."
The team used a scanning probe to follow up the behavior and position of the qubits. One of the many interesting findings shows that the qubit's correlation occurs at 16 nanometers and not at 20 nanometers as theory expected, which might not seem like a huge difference but it is very important. They are currently the only group in the world that has an approach that tells them exactly the position of where their qubits are.
Quantum computing holds the promise of revolutionizing information technology. By harnessing the power of quantum mechanics, researchers expect to create devices that are faster and more powerful than anything that can be achieved currently, even with supercomputers. From new tech to new medicine, quantum computers could be used to simulate things like never before.