‘Magnetic graphene’ forms a new kind of magnetism

EurekAlert  February 8, 2021 An international team of researchers ( UK, Uzbekistan, Russia, France, USA – Oak Ridge National Laboratory, Vietnam, South Korea, Czech Republic) was able to control the conductivity and magnetism of iron thiophosphate (FePS3) which undergoes a transition from an insulator to a metal when compressed. Using new techniques to measure the magnetic structure up to record-breaking high pressures, they found that magnetism survives, but gets modified into new forms, giving rise to new quantum properties in a new type of magnetic metal. The ‘spin’ of the electrons has been shown to be the source of magnetism. […]

‘Multiplying’ light could be key to ultra-powerful optical computers

EurekAlert  February 8, 2021 An international team of researchers (Russia, UK) found that optical systems can combine light by multiplying the wave functions describing the light waves instead of adding them and may represent a different type of connections between the light waves. If the coupling and light intensity is right, the light multiplies, affecting the phases of the individual pulses, giving away the answer to the problem. They found that there is no need to project the continuous light phases onto ‘0’ and ‘1’ states necessary for solving problems in binary variables. Instead, the system tends to bring about […]

New concept for rocket thruster exploits the mechanism behind solar flares

Science Daily  January 28, 2021 Current plasma thrusters that use electric fields to propel the particles can only produce low specific impulse. The device proposed by researchers at Princeton Plasma Physics Laboratory would apply magnetic fields to cause particles of plasma to shoot out of a rocket and propel the craft forward. The particles are accelerated using magnetic reconnection which also occurs in tokamaks. They showed that the new plasma thruster concept can generate exhaust with velocities of hundreds of kilometers per second, 10 times faster than those of other thrusters. According to the researchers the new concept provides the […]

New mathematical method for generating random connected networks

Science Daily  February 10, 2021 Many natural and human-made networks, such as computer, biological or social networks have a connectivity structure that critically shapes their behavior. Existing algorithms that create connected networks with a specific number of connections for each node suffer from uncontrolled bias potentially compromising the conclusions of the study. Researchers in Germany have developed a new method for the random sampling of connected networks with a specified degree sequence considering both the case of simple graphs and that of loopless multigraphs. Their method builds on a recently introduced novel sampling approach that constructs graphs with given degrees […]

An optical coating like no other

Nanowerk  February 5, 2021 An international team of researchers (USA – University of Rochester, Case western University, Italy) applied a 15 nanometer-thick film of germanium to a metal surface resulting in a surface capable absorbing a broad band of wavelengths. Combining it with a cavity that supports a narrowband resonance resulted in coupled cavities that exhibit Fano resonance that can reflect a very narrow band of light. The semi-transparent Fano resonance optical coationgs (FROCs) can transmit and reflect the same colour as a beam splitter filter. FROCs can spectrally and spatially separate the thermal and photovoltaic bands of the solar spectrum, […]

Quantum effects help minimize communication flaws

EurekAlert  February 10, 2021 Both quantum computation and quantum communication are strongly deteriorated because quantum superposition state can be destroyed, or entanglement between two or more quantum particles can be lost. An international team of researchers (Austria, UK, Hong Kong, Switzerland, France, Canada) experimentally and numerically compare different ways in which two trajectories through a pair of noisy channels can be superposed. They observed that, within the framework of quantum interferometry, the use of channels in series with quantum-controlled operations generally yields the largest advantages. The results contribute to clarify the nature of these advantages in experimental quantum-optical scenarios and […]

Quantum systems learn joint computing

Phy.org  February 5, 2021 The big challenge in quantum computing is to realize scalable multi-qubit systems with cross-talk–free addressability and efficient coupling of arbitrarily selected qubits. Quantum networks promise a solution by integrating smaller qubit modules to a larger computing cluster. Such a distributed architecture, however, requires the capability to execute quantum-logic gates between distant qubits. An international team of researchers (Germany, Spain) experimentally realized such a gate over 60 meters. They employed an ancillary photon that they successively reflected from two remote qubit modules, followed by a heralding photon detection, which triggers a final qubit rotation. They used the […]

Scientists create armor for fragile quantum technology

Phys.org  February 8, 2021 Integration of TMDCs into practical all‐dielectric heterostructures hinges on the ability to passivate and protect them against necessary fabrication steps on large scales. An international team of researchers (Australia, Germany) has created the protective layer by exposing a droplet of liquid gallium to air, which immediately formed a perfectly even three nanometers thick layer of gallium oxide on its surface. By squashing the droplet on top of the 2D material with a glass slide, the gallium oxide layer can be transferred from the liquid gallium onto the material’s entire surface, up to centimetres in scale. Because […]

Silicon waveguides move us closer to faster, light-based logic circuits

Phys.org  February 8, 2021 Wiring up the transistors of an optical circuit with silicon waveguides is an important requirement to make compact, highly integrated chips. However, silicon is a strong absorber of visible light. To circumvent the absorption issue researchers in Switzerland used high contrast grating consisting of nanometer sized “posts” lined up in such a way that light passing through the posts interferes destructively with light passing between posts making sure that no light can “leak” through the grating. Most of the light gets reflected inside the waveguide. They showed that there was a loss of only 13 percent […]

UMass Amherst team helps demonstrate spontaneous quantum error correction

EurekAlert  February 11, 2021 Existing demonstrations of quantum correction codes (QEC) are hardware intensive and prone to introducing and propagating errors. A team of researchers in the US (UMass Amherst, Northwestern University) encoded a logical qubit in Schrödinger cat-like multiphoton states of a superconducting cavity and demonstrated a corrective dissipation process that stabilizes an error-syndrome operator, the photon number parity. Implemented with continuous-wave control fields only, this passive protocol protects the quantum information by autonomously correcting single-photon-loss errors and boosts the coherence time of the bosonic qubit by over a factor of two. QEC is realized in a modest hardware […]