In quantum mechanics, the act of measurement produces unavoidable perturbation (also called “back-action”) on the state of the measured system. This effect is, in many cases, not desirable, as back-action often limits the precision of repeated measurements. However, so-called Quantum Non-Demolition (QND) measurements ensure that the unavoidable and deleterious back-action is diverted onto other system […]
A collaboration between Harvard University with scientists at QuEra Computing, MIT, University of Innsbruck and other institutions has demonstrated a breakthrough application of neutral-atom quantum processors to solve problems of practical use. Previously, neutral-atom quantum processors had been proposed to efficiently encode certain hard combinatorial optimization problems. In this landmark publication, the authors not only […]
Researchers report a breakthrough in frequency up-conversion of single photons, based on a hollow-core Photonic Crystal Fiber (PCF) filled with hydrogen gas. First a spatio-temporal hologram of molecular vibrations is created in the gas by stimulated Raman scattering. This hologram is then used for highly efficient, correlation-preserving frequency conversion of single photons. The system operates […]
Researchers at Stony Brook University report the formation of matter-wave polaritons in an optical lattice, an experimental discovery that permits studies of a central QIST paradigm through direct quantum simulation using ultracold atoms. The scientists project that their novel quasiparticles, which mimic strongly interacting photons in materials and devices but circumvent some of the inherent […]
A new theorem from researchers at the RIKEN Center for Advanced Intelligence Project, Tokyo, and Keio University, Yokohama, provides an understanding of what types of long-range quantum entanglement survive at non-zero temperatures, revealing a fundamental aspect of macroscopic quantum phenomena and guiding the way towards further understanding of quantum systems and designing new room-temperature stable […]
Researchers at University of Cologne have analyzed cutting-edge device structures of quantum computers to demonstrate that some of them are indeed operating dangerously close to a threshold of chaotic meltdown. The challenge is to walk a thin line between too high, but also too low disorder to safeguard device operation. Qubits interlinked to form a […]
Determining whether a noisy quantum channel can be used to reliably transmit quantum information is a challenging problem in quantum information theory. This is because it requires computation of the channel’s coherent information for an unbounded number of copies of the channel. A team of researchers has devised an elementary perturbative technique to solve this […]
Developing non-classical light sources that can emit, on-demand, exactly one photon at a time is one of the main requirements of quantum technologies. But although the first demonstration of such a “single photon emitter”, or SPE, dates back to the 1970s, their low reliability and efficiency has been stood in the way of any meaningfully […]
Researchers from QuTech, in collaboration with Fujitsu and Element Six, have demonstrated the fault-tolerant operation of a quantum bit using a quantum processor based on spin qubits in diamond. The team has realized a logical qubit using their recently introdued 29-qubit quantum processor. Their qubits consist of electron and nuclear spins associated with a nitrogen-vacancy […]
A team led by the U.S. Department of Energy’s (DOE) Argonne National Laboratory has announced the creation of a new qubit platform formed by freezing neon gas into a solid at very low temperatures, spraying electrons from a light bulb’s filament onto the solid, and trapping a single electron there. This system shows great promise […]
