Phys.org December 5, 2022 To understand the inner workings of quantum computing and enable supercomputing a team of researchers in the US (Iowa State University, University of Alabama at Birmingham, University of Wisconsin-Madison, Madison, Florida State University, Ames National Laboratory) built a Cryogenic Magneto-Terahertz Scanning Near-field Optical Microscope (cm-SNOM). It comprises three main equipment: i) a 5 T split pair magnetic cryostat with a custom made insert for mounting SNOM inside; ii) an atomic force microscope (AFM) unit that accepts ultrafast THz excitation and iii) a MHz repetition rate, femtosecond laser amplifier for high-field THz pulse generation and sensitive detection. […]
On-demand storage of photonic qubits at telecom wavelengths
Phys.org December 6, 2022 Researchers in China processed a fiber-integrated quantum memory at telecom wavelengths based on a laser-written waveguide fabricated in an erbium-doped yttrium silicate. Both ends of the waveguide memory were directly connected with fiber arrays with a fiber-to-fiber efficiency of 51%. Storage fidelity of 98.3(1)% was obtained for time-bin qubits encoded with single-photon-level coherent pulses, which is far beyond the maximal fidelity that can be achieved with a classical measure and prepared strategy. This device featured high reliability and easy scalability, and it can be directly integrated into fiber networks, which could play an essential role in […]
Photonics – extending the spectrum
Nanowerk December 6, 2022 Despite remarkable manufacturing advantages, reliance on silicon-based waveguides currently limits the spectral window available to photonic integrated circuits (PICs). A team of researchers in the US (industry, UC Santa Barbara, Caltech) has developed a technique to enable photonic chips to operate in the visible-to-near-infrared spectrum by directly uniting III–V materials with silicon nitride waveguides on Si wafers. Using this technology, they fabricated a fully integrated PIC at photon energies greater than the bandgap of silicon, demonstrating essential photonic building blocks, including lasers, amplifiers, photodetectors, modulators, and passives, all operating at submicrometre wavelengths. Using this platform, they […]
Proposing a new idea for spacecraft propulsion that involves dynamic soaring
Phys.org December 6, 2022 Inspired by the dynamic soaring maneuvers performed by sea birds and gliders in which differences in wind speed are exploited to gain velocity, an international team of researchers (Canada, USA – industry) proposed a technique in which a lift-generating spacecraft circles between regions of the heliosphere that have different wind speeds, gaining energy in the process without the use of propellant and only modest onboard power requirements. Detailed models of the spacecraft trajectory were developed to predict the potential velocity gains and the maximum velocity that might be achieved in terms of the lift-to-drag ratio of […]
Quantum leap for research into unhackable communications networks
Phys.org November 30, 2022 Quantum steering relaxes the strict technological constraints of Bell nonlocality by reframing it in an asymmetric manner, with a trusted party only on one side. However, tests of quantum steering still require either extremely high-quality entanglement or very low loss. An international team of researchers (UK, Switzerland) constructed a test of quantum steering for qudits harnessing the advantages of high-dimensional entanglement to be simultaneously noise robust and loss tolerant. It was designed for single-detector measurements and was able to close the fair-sampling loophole in a time-efficient manner. They demonstrated quantum steering in up to 53 dimensions, […]
Researchers advance insights into cause of ripples on icicles
Science Daily December 5, 2022 Icicles that have grown from slightly impure water develop ripples around their circumference. The ripples have a near-universal wavelength and are thought to be the result of a morphological instability. Researchers in Canada used laboratory-grown icicles and various species of impurities, including fluorescent dye, to show that a certain fraction of the impurities remains trapped inside the icicle, forming inclusions within the ice. The inclusions were organized into chevron patterns aligned with the peaks of the ripples. Within the chevrons, there was a substructure of crescent-shaped structures. They also examined the crystal grain structure of […]
Researchers use ultrasound waves to move objects hands-free
Science Daily December 6, 2022 The transfer of wave momentum is a fundamental mechanism for contactless manipulation, yet the rules of conventional scattering intrinsically limit the radiation force based on the shape and the size of the manipulated object. Researchers at the University of Minnesota showed that this intrinsic limit can be broken for acoustic waves with subwavelength metasurfaces. Harnessing anomalous metasurface scattering, they demonstrated self-guidance, where a metasurface object is autonomously guided by an acoustic wave, and tractor beaming, where a metasurface object is pulled by the wave. According to the researchers their results show that bringing the metasurface […]
Single-electron devices could manage heat flow in electronic components
Nanowerk December 8, 2022 Previous heat engines based on quantum dots have used reservoirs of electrons at different temperatures. An international team of researchers (Japan, Germany) has fabricated a nanoscale ‘heat engine’ that uses a property of spin as the effective working medium. They confined electrons using electric fields generated at surface metal electrodes on a gallium arsenide surface. The device had two interlinked quantum dots and a built-in charge sensor to passively monitor what was going on within the double quantum dot. A third quantum dot was used to control the double quantum dot’s thermal environment. According to the […]
Soft robot detects damage, heals itself
Science Daily December 7, 2022 Researchers at Cornell University have introduced damage intelligent soft-bodied systems via a network of self-healing light guides for dynamic sensing (SHeaLDS). Exploiting the intrinsic damage resilience of light propagation in an optical waveguide, in combination with a tough, transparent, and autonomously self-healing polyurethane urea elastomer, SHeaLDS enabled damage resilient and intelligent robots by self-healing cuts as well as detecting this damage and controlling the robot’s actions accordingly. With optimized material and structural design for hyperelastic deformation of the robot and autonomous self-healing capacity, SHeaLDS provided reliable dynamic sensing at large strains with no drift or […]
Unexpected speed-dependent friction with graphene
Nanowerk, December 6, 2022 Graphene is being examined with a view to potential use as a lubricating layer. If it is applied to a platinum surface, it has a significant impact on the measurable friction forces. An international team of researchers (Israel, Switzerland) has reported that, in this instance, the friction depends on the speed at which the tip of an atomic force microscope (AFM) is moved across the surface. In conjunction with the platinum substrate, graphene no longer forms only the hexagonal honeycomb pattern of carbon atoms and instead forms Moiré superlattices. The surface is then no longer completely […]