Qubits that operate at room temperature

Phys.org  March 17, 2020 Defect-based quantum systems are often complicated by charge-state instabilities and interference by phonons, which can diminish spin-initialization fidelities and limit room-temperature operation. An international team of researchers (Hungary, Sweden, USA – Argonne National Laboratory, University of Chicago, IBM, Russia) identified a pathway around these drawbacks by showing that an engineered quantum well can stabilize the charge state of a qubit. They constructed a model for previously unattributed point defect centers in silicon carbide as a near-stacking fault axial divacancy and show how this model explains these defects’ robustness against photoionization and room temperature stability. These results […]

Uncovering the hidden “noise” that can kill qubits

MIT News  September 16, 2019 Statistics-based models to estimate the impact of unwanted noise sources surrounding qubits to create new ways to protect them generally capture simplistic Gaussian noise. A team of researchers (MIT, Dartmouth College) developed a technique to separate non-Gaussian noise from the background Gaussian noise, and then used signal-processing techniques to reconstruct highly detailed information about those noise signals. The key innovation behind the work is carefully engineering the pulses to act as specific filters that extract properties of the “bispectrum,” a two-dimension representation that gives information about distinctive time correlations of non-Gaussian noise. Those reconstructions can […]

Researchers build transistor-like gate for quantum information processing — with qudits

EurekAlert  July 16, 2019 A team of researchers in the US (Purdue University, Oak Ridge National Laboratory) implemented qudit gate with a set of standard off-the-shelf equipment used daily in the optical communication industry. Qudits exist in multiple states, such as 0 and 1 and 2. More states mean that more data can be encoded and processed. They achieved more entanglement with fewer photons by encoding one qudit in the time domain and the other in the frequency domain of each of the two photons. They built a gate using the two qudits encoded in each photon, for a total […]

Multi-functional quantum bits for future computers

Eurekalert  October 29, 2018 Researchers in Germany are working on Scalable Rare Earth Ion Quantum Computing Nodes (SQUARE) within the framework of the Quantum Technology Flagship funded by the European Commission. SQUARE is aimed at establishing rare earth ions that can be addressed separately as basic building blocks for scalable quantum technologies. In particular, it is planned to demonstrate functional elements of a multi-qubit quantum register that can be read out optically and to realize building blocks of a quantum network. Their work was presented at a recent conference in Germany… read more.