In a substantial breakthrough for quantum computing, researchers at the University of Chicago just sent entangled qubit states through a communication cable linking one quantum network node to another, according to a recent study published in the journal Nature.
The initial results of this study bring us closer to making quantum computing a reality — laying the critical groundwork for future quantum communication networks.
Quantum computing breakthrough
Qubits — also called quantum bits — are the fundamental units of quantum information. And, using their quantum properties like superposition — in addition to their capacity for entanglement — scientists and engineers are building the next-gen quantum computers capable of solving quantitative problems dwarfing the abilities of modern-day computers.
The researchers — working from the Pritzker School of Molecular Engineering (PME) at the University of Chicago (UChicago) — also successfully amplified an entangled state using a single cable to entangle two qubits in each of the two nodes, and then further entangled these qubits with other qubits in the nodes, according to a blog post shared on UChicago's website.
"Developing methods that allow us to transfer entangled states will be essential to scaling quantum computing," said the lead scientist of the new research, Professor Andrew Cleland.
Quantum states transmitted in the form of microwave photons
The scientists of Cleland Lab used superconducting qubits — which are tiny cryogenic circuits capable of electrical manipulation — to complete their research.
To transmit entangled states via communication cable — which was a 3.28-ft (1-m) long superconducting cable — the researchers constructed an experimental procedure where each of the two nodes had three superconducting qubits. The scientists connected one qubit in either node to the cable, and then transmitted quantum states in the form of microwave photons — and witnessed a minimal loss of information.
Since quantum states are extremely fragile, the scientists faced a daunting challenge.
Extremely rapid transfer process minimized information loss
A former postdoctoral fellow of Cleland named Youpeng Zhong built a system where the entire transfer process — going from one node through the cable to the other node — took only a few tens of nanoseconds, or one billionth of a second.
To put this speed in perspective, a human lifespan doesn't even last one billion minutes. This extremely short burst of time allowed the research team to send entangled quantum states without losing too much information.
The researchers' system also enabled them to "amplify" qubit entanglement. In other words, they entangled the qubits in either node together by basically sending one half-proton through the cable. Then they extended this entanglement to the other qubits in either node, and when the process was finished, all six qubits in the two nodes were entangled into a single, "globally" entangled state.
The quantum computing revolution is coming
In the future, scientists (and probably commercial entities) will likely build quantum computers out of modules — where "families" of entangled qubits carry out an extremely complex computation. These future computers may eventually consist of many such networked modules — like how modern-day supercomputers conduct parallel computing via many interconnected central processing units.
"These modules will need to send complex quantum states to each other, and this is a big step toward that," said Cleland in the blog post. "We want to show that superconducting qubits have a vital role going forward."
With the coming dawn of quantum computers, theoretical solutions for unconscionably complex math problems — with substantial relevance for theoretical physics — will finally have the computing power they demand. Encryption will transform how we communicate, and help transform telecommunications infrastructure and roads in ways even smart city initiatives have yet to imagine.
This was a breaking story and was regularly updated as new information became available.