'A new twist?' Real-time quantum noise mitigation

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Real-time noise mitigation

Researchers at the Niels Bohr Institute, MIT, Norwegian University of Science and Technology, and Leiden University introduced a new protocol for calibrating the frequency of a resonantly driven qubit. The team used a Quantum Machines controller with an integrated FPGA to generate adaptive probing sequences for qubit-frequency estimation and then adjust the control path that manipulates qubits in order to mitigate noise.

Called “frequency binary search,” the protocol’s calibration precision scales exponentially with the number of measurements taken and can calibrate across numerous qubits simultaneously.

This work, “Efficient Qubit Calibration by Binary-Search Hamiltonian Tracking,” was published in PRX Quantum.

Leiden ‘lie detector’

Likening their work to a “quantum lie detector,” researchers at Leiden University, Tsinghua University, and Zhejiang University showed “genuine multipartite Bell-operator correlations” in systems with up to 73 qubits. Using a superconducting processor to consider the low-energy state of a two-dimensional honeycomb model, the team measured energies that were, in some cases, 48 standard deviations below what a classical system would produce. They argued that this approach to confirming quantum behavior offers “a finer benchmark beyond entanglement for quantum devices.”

This work, “Probing Many-Body Bell Correlation Depth with Superconducting Qubits,” was published in Physical Review X.

Q-chip

Researchers at the University of Pennsylvania developed a “Q-chip” that can manage quantum signals on a live commercial optical network using the same protocols that run the internet. The chip also automatically corrects for noise, bundles quantum and classical data into standard internet-style packets, and routes them.

A classical signal with header information “travels just ahead of the quantum signal,” lead author Yichi Zhang said. “That allows us to measure the classical signal for routing, while leaving the quantum signal intact.”

This work, “Classical-decisive Quantum Internet by Integrated Photonics,” was published in Science.

Quantum liquid crystal

Combining a Weyl semimetal and an insulating magnetic material known as spin ice and subjecting them to a powerful magnetic field, Rutgers physicists induced a new quantum state that they called a “quantum liquid crystal.” The material exhibited electronic anisotropy, in which the material conducts electricity differently in different directions. The experiments were run at the National High Magnetic Field Laboratory, which is supported by NSF and the state of Florida, and builds on a study published in Nano Letters earlier in the year.

This work, “Electronic Anisotropy and Rotational Symmetry Breaking at a Weyl Semimetal/Spin Ice Interface,” was published in Science Advances.

Quickbits

• Bridging paradigms: Designing for HPC-Quantum convergence (Future Generation Computer Systems)

• Energy-efficient cryogenic ternary content addressable memory using ferroelectric SQUID (npj Unconventional Computing)

• Montana State opens quantum computing facility

Quantum Campus is edited by Bill Bell, a science writer and marketing consultant who has covered physics and high-performance computing for more than 25 years. Disclosure statement.