Researchers are constantly dealing with how to read the information held in qubits. Quantum science involves many practical applications including hackerproof communication networks or quantum computers that can accelerate new drug discovery. Such applications require a quantum version of a computer bit, known as a qubit.
According to a press statement, a team of researchers at the U.S. Department of Energy’s Argonne National Laboratory and the University of Chicago have achieved major breakthroughs to overcome the common challenges for quantum systems. These breakthroughs include scientists’ ability to read out their qubits on demand and keep the quantum state intact for about 5 seconds.
The team used a method called “single-shot readout” for reading a qubit on demand. Moreover, as far as the extended quantum states of qubits are concerned, the method uses precise laser pulses to add single electrons to qubits, depending on their quantum size. This has been published by the team in the journal Science Advances.
Due to environmental noise, qubits easily lose their information. That is why keeping them intact for extended periods is a difficult task in quantum science. “It’s uncommon to have quantum information preserved on these human timescales,” said David Awschalom, senior scientist at Argonne National Laboratory.
“Five seconds is long enough to send a light-speed signal to the moon and back,” Awschalom continued. “That’s powerful if you’re thinking about transmitting information from a qubit to someone via light. That light will still correctly reflect the qubit state even after it has circled the Earth almost 40 times — paving the way to make a distributed quantum internet.”
In order to reduce the background noise, researchers used highly purified silicon carbide samples to make qubits. Silicon carbide is widely used in a commercial capacity so, it should be easy to scale up. Then by using precise microwave pulses, they extended the amount of time to over five seconds via a concept known as “coherence”.
“These pulses decouple the qubit from noise sources and errors by rapidly flipping the quantum state,” said Chris Anderson of the University of Chicago, co-first author of the paper. “Each pulse is like hitting the undo button on our qubit, erasing any error that may have happened between pulses.”