Deciphering the deep dynamics of electric charge

Phys.org  February 6, 2024 Unraveling local dynamic charge processes relies on the ability to map charge carrier motion across multiple length- and timescales and understanding how these processes interact with the inherent material heterogeneities. An international team of researchers (South Korea, USA – Oak Ridge National Laboratory, Case Western University, Australia) introduced high-speed sparse scanning Kelvin probe force microscopy, which combined sparse scanning and image reconstruction. They showed that with their approach sub-second imaging of nanoscale charge dynamic was possible. They demonstrated electrochemically mediated diffusion of mobile surface ions on a LaAlO3/SrTiO3 planar device. By monitoring the diffusion of oxygen […]

Joint research team develops edge-to-edge assembly technique for 2D nanosheets

Phys.org  February 2, 2024 Despite remarkable advancements, the controlled assembly of highly anisotropic 2Dnanosheets is significantly challenging, primarily due to the limited availability of selective edge-to-edge connectivity compared to the abundant large faces. Researchers in South Korea have shown controlled self-assembly of 2D-silica nanosheets (2D-SiNSs) into hollow micron-sized soccer ball-like shells (SA-SiMS). The assembly was driven by the physical flexibility of the 2D-SiNSs and the differential electric double-layer charge gradient creating electrostatic bias on the edge and face regions. The resulting SA-SiMS structures exhibited high mechanical stability, even at high-temperatures, and exhibited excellent performance as catalyst support in the dry […]

Key innovation in photonic components could transform supercomputing technology

Phys.org  February 5, 2024 Researchers in South Korea demonstrated the array-level tunable couplers and phase shifters with capacitive electrostatic microelectromechanical actuators in a recirculating mesh network. The overall fabrication process was compatible with the conventional wafer-level passive silicon photonics platform. Extremely low unit-level standby power consumption of and reconfiguration energy with <11 V programming voltages offered well-balanced, scalable routes for efficient phase and amplitude modulation of the guided lightwaves with sub-decibel optical losses. The extinction ratios of the continuously tunable directional coupler exceed 30 dB. Full 2π-phase shifting could be achieved with a modulation efficiency of less than 0.075 V cm and a phase-dependent […]

Magnesium protects tantalum, a promising material for making qubits

Phys.org  February 5, 2024 To scale up superconducting quantum circuits based on transmon qubits, substantial enhancements in qubit coherence time is necessary. Tantalum (Ta) has emerged as a promising candidate in this regard. However, amorphous surface Ta oxide layer may introduce dielectric loss limiting the coherence time. A team of researchers in the US (Brookhaven National Laboratory, Pacific Northwest National Laboratory, Princeton University) developed a new approach for suppressing the formation of tantalum oxide using an ultrathin magnesium (Mg) capping layer. They demonstrated that oxide was confined to an extremely thin region directly beneath the Mg/Ta interface, and that the […]

Nano weaving creates ‘Chinese knot’ magnetism for powerful microwave shielding

Nanowerk  February 7, 2024 Harnessing tailored nanoscale magnetic materials like metal-organic frameworks for advanced applications has faced two key challenges – reliably constructing these frameworks with specific and programmable architectural arrangements and effectively characterizing these nanostructures. Researchers in China strategically dispersed magnetic Co nanoparticles into a meticulously layered nanoporous framework with the bottom and upper nanopores exhibiting a staggered arrangement. The staggered nanoporous structure intricately shapes the magnetic flux lines into a Chinese knot shape, significantly altering its magnetic characteristics. Such a transformation remarkably enhances the material’s efficacy in absorbing electromagnetic waves, covering the Ku band even at a minimal […]

New ion cooling technique could simplify quantum computing devices

Phys.org  February 6, 2024 In current QCCD implementations, imperfect ion transport and anomalous heating can excite ion motion during a calculation. To counteract this, intermediate cooling is necessary to maintain high-fidelity gate performance. Cooling the computational ions sympathetically with ions of another species creates a significant runtime bottleneck. Researchers at the Georgia Institute of Technology demonstrated exchange cooling which does not require trapping two different atomic species. They introduced a bank of “coolant” ions which were repeatedly laser cooled. A computational ion could be cooled by transporting a coolant ion into its proximity. Experimentally they tested this concept and executed […]

Progress on chip-based spontaneous four-wave mixing quantum light sources

Phys.org  February 2, 2024 Integrated quantum photonics has enabled the generation, manipulation, and detection of quantum states of light with steadily increasing scale and complexity levels. The exploration of on-chip integration has accumulated substantial progresses in recent years toward the realization of low-cost, large-scale quantum photonic circuits. Researchers in China reviewed the underlying mechanism and discuss state-of-the-art SFWM on-chip quantum light sources fabricated with various structures and materials on chip. They enumerated the most appealing applications of on-chip SFWM such as heralding single-photon source, entangled photon source, and system-level integration… read more. Open Access TECHNICAL ARTICLE 

Reading on screens instead of paper is a less effective way to absorb and retain information, suggests research

Phys.org  February 5, 2024 Evidence from recent experiments suggests a complex interplay of visual and cognitive influences on how people engage with digital reading. According to the researchers in Australia although readers can strategically adjust their reading behaviors in response to their immediate reading context, the efficacy of these strategies depends on cognitive, metacognitive, and motivational factors. Comprehension tends to be less effective when reading on screens than on paper, particularly with texts that require a deeper understanding or when reading under time pressure. Recent evidence indicates that digital readers exhibit a tendency towards more shallow or superficial text processing […]

Research team takes a fundamental step toward a functioning quantum internet

Phys.org  February 7, 2024 Quantum repeater networks require independent absorptive quantum memories capable of storing and retrieving indistinguishable photons to perform high-repetition entanglement swapping operations. An international team of researchers (USA – Stony Brook University, industry, Brookhaven National Laboratory, Italy) performed Hong-Ou-Mandel (HOM) interference between photonic polarization states and single-photon-level pulses stored and retrieved from two sets of independent room-temperature quantum memories. They showed that the storage and retrieval of polarization states from quantum memories did not degrade the HOM visibility for few-photon-level polarization states in a dual-rail configuration. For single-photon-level pulses, they measured the HOM visibility with various levels […]

Scientists shed light on the inner workings of a new class of unconventional superconductors

Phys.org  February 7, 2024 The discovery of superconductivity in infinite-layer nickelates established another category of unconventional superconductors that shares structural and electronic similarities with cuprates. However, key issues of the superconducting pairing symmetry, gap amplitude and superconducting fluctuations are yet to be addressed. A team of researchers in the US (Ames National Laboratory, SLAC National Laboratory, Stanford University) utilized static and ultrafast terahertz spectroscopy and demonstrated that the equilibrium terahertz conductivity and non-equilibrium terahertz responses of an optimally Sr-doped nickelate film are in line with the electrodynamics of d-wave superconductivity in the dirty limit. The gap-to-Tc ratio of 3.4 indicated […]