Quantum science promised us many technological applications. This includes building hackerproof communication networks. This also includes quantum computers that could accelerate new drug discovery. These applications need a quantum version of a computer bit. It is known as qubit. It stores quantum information.
Scientists are still grappling with how to easily read the information held in these qubits. They are struggling with the short memory time and coherence of qubits. It is usually limited to microseconds or milliseconds.
U.S. Department of Energy’s Argonne National Laboratory and the University of Chicago scientists have achieved two major breakthroughs to overcome these common challenges for quantum systems. Scientists were able to read out their qubit on demand. They then keep the quantum state intact for over five seconds. This is a new record for this class of devices. The researchers’ qubits are made from an easy-to-use material. This material is called silicon carbide. It is found in lightbulbs, electric vehicles and high-voltage electronics.
Scientists created a qubit system which can be made in common electronics. Scientists hope to open a new avenue for quantum innovation. They used a technology that is both scalable and cost-effective.
The research paper has been published in the journal Science Advances.
10,000 times more signal
The first breakthrough for the scientists was to make the silicon carbide qubits easier to read.
Each computer needs a way to read information encoded into its bits. For semiconductor qubits the typical readout method is to address the qubits with lasers and measure the light emitted back. The process is challenging. Because it needs detecting single particles of light called photons very efficiently.
Scientists used carefully designed laser pulses to add a single electron to their qubit. This depended on its initial quantum state, either zero or one. With a laser, the qubit is read out in the same way as before.
Scientists could focus on making their quantum states last as long as possible, armed with the single shot readout method. This is a notorious challenge for quantum technologies. As qubits easily lose their information due to noise in their environment.
Scientists grew highly purified samples of silicon carbide. It reduced the background noise that tends to interfere with their qubit functioning. Then they applied a series of microwave pulses to the qubit. Then extended the amount of time that their qubits preserved their quantum information. This concept is known as “coherence.” Scientists think that even longer coherences should be possible. They extended coherence time which had significant ramifications. This includes how complex an operation a future quantum computer can handle.