Caltech Scientists Stretch Quantum Memory Lifetimes 30x in Major Leap

Quantum computing leaps forward -- A team of Caltech researchers says they've reached a pivotal milestone in quantum computing (quotes). By Semirah Dolan August 28, 2020 Quantum computing has taken one more giant step forward as Caltech researchers have announced that they've developed a technique for quantum states to survive 30 times longer than had previously ever been achieved. Unlike with the bits of classical computers, quantum systems work with qubits, able to be in more than one state simultaneously through a property known as superposition.

This ability means that quantum machines can potentially solve problems that are completely out of reach for classical computers. But keeping hold of these delicate states has remained one of the biggest challenges in scaling up quantum technologies.

Caltech Hybrid System Uses Sound Waves to Extend Quantum Memory 30-Fold

According to a paper published in Nature Physics, the Caltech researchers accomplished this by linking superconducting qubits to mechanical oscillators that store information within sound waves, or phonons. The work, led by graduate students Alkim Bozkurt and Omid Golam as well as assistant professor Mohammad Mirhosseini, shows that quantum data can, in fact, be more efficiently compressed and transported when it is stored temporarily in sound. Acoustic vibrations are a natural match to the very cold environment of superconducting qubits, say the authors.

The device, which is akin to a tiny tuning fork, relies on vibrating plates to harbour electrical signals that possess quantum information. Measurements indicated that the stored information lasted 30 times longer than with current superconducting qubits. Qubits are excellent for doing the processing but not so great at storing it for long periods of time, which is why this hybrid approach is a significant breakthrough, says Mirhosseini. His team emphasised that quantum memory is necessary for so-called calculations “where you access some of the results later in the calculation.”

Unlike electromagnetic waves, mechanical vibrations do not leak out so easily into space — so they lose less of their energy — and they can therefore be stored for longer. The researchers believe that due to the small size of the oscillators, it should be possible to fit several hundred of them on a single chip.

This, in turn, may offer a possible path towards a more powerful and efficient quantum computer.
Paying for the project were the Air Force Office of Scientific Research and the National Science Foundation, and it was co-written by Yue Yu and Hao Tian. Quantum computing should be more interactive, says new AIMR research.