Phys.org November 8, 2023 The use of single electron spins in quantum dots as qubits requires detailed knowledge about the processes involved in their initialization and operation as well as their relaxation and decoherence. In optical schemes for such spin qubits, spin-flip Raman as well as Auger processes play an important role, in addition to environment-induced spin relaxation. An international team of researchers (Germany, USA – UCLA) demonstrated how to quantitatively access all the spin-related processes in one go by monitoring the charge fluctuations of the quantum dot. They used resonance fluorescence and analyzed the charge fluctuations in terms of […]
In a surprising finding, light can make water evaporate without heat
Nanowerk November 2, 2023 Solar-driven evaporation rates using porous absorbers have been reported to exceed the theoretical thermal evaporation limit, but the mechanism of this phenomenon remains unclerogel materials was negligible. 2) Illumination of hydrogel under solar or visible-spectrum light-emitting diode led to evaporation rates exceeding the thermal evaporation limit, even in hydrogels without additional absorbers. 3) The evaporation rates were wavelength dependent, peaking at 520ar. Researchers at MIT found many unexpected results in their experiments: 1) Partially wetted hydrogels became absorbing in the visible spectral range, where the absorption by both the water and the hydrogel material is negligible. […]
Light-powered MOFs make seawater drinkable with the flip of a switch
Nanowerk November 4, 2023 Researchers in China have reported a kind of light-responsive MOF adsorption material which was fabricated by covalently immobilizing photoactive spiropyran (SP) molecules onto a chromium(III)-based amino-tagged MIL-101 framework through amide linkages. The photoisomerization of SP moieties provided these materials with reversible binding to metal ions. In the dark, the SP-modified MOFs were capable of adsorbing multiple monovalent and divalent salts from saline water and effectively released the adsorbed ions into water upon exposure to simulated sunlight. The MOFs showed excellent salt adsorption capacity, of which the MOF with an SP modification ratio of 39% had an […]
Liquid metal skins turned into power source for stretchable batteries and devices
Nanowerk November 6, 2023 Liquid metals which behave like liquid at room temperature have unique mechanical and electrical properties which make them favorable for soft electronics and stretchable conductors. They form a thin oxide layer on their surface. Researchers at the Boston University have introduced a new approach where liquid metal oxide served as an electrochemical energy source. By mechanically rupturing their surface oxide, liquid metals formed a galvanic cell and converted their chemical energy to electrical energy. When dispersing liquid metals into an ionically-conductive liquid to form emulsions, this composite material provided ∼500 mV of open-circuit voltage and up […]
Neuromorphic computing will be great… if hardware can handle the workload
Nanowerk November 7, 2023 Ramp-reversal memory has recently been discovered in several insulator-to-metal transition materials where a non-volatile resistance change can be set by repeatedly driving the material partway through the transition. An international team of researchers (USA – Purdue University, University of Colorado, UCSD, France) has successfully developed a single-photon light source consisting of doped ytterbium ions (Yb3+) in an amorphous silica optical fiber at room temperature. They used optical microscopy to track the location and internal structure of accumulated memory as a thin film of VO2 was temperature cycled through multiple training subloops. The measurements revealed that the […]
Optical-fiber based single-photon light source at room temperature for next-generation quantum processing
Science Daily November 2, 2023 Rare-earth (RE) atoms in solid-state materials are attractive components for photonic quantum information systems because of their coherence properties even in high-temperature environments. Researchers in Japan performed the single-site optical spectroscopy and optical addressing of a single RE atom in an amorphous silica optical fiber at room temperature. The single-site optical spectroscopy of the tapered RE-doped fiber showed nonresonant emission lines similar to those seen in the case of an unstructured fiber and the autocorrelation function of photons emitted from the fiber showed the antibunching effect due to the spatial isolation given by the tapered […]
Research shows that photorespiration does not protect against fluctuating light conditions
Phys.org November 7, 2023 It has been hypothesized that a specific metabolic pathway in photosynthesis that competes with carbon fixation has a protective function for plants. To test this hypothesis an international team of researchers (Germany, USA – Michigan State University) characterized plants with varying PR enzyme activities under fluctuating and non-fluctuating light conditions. Contrasting their expectations, growth of mutants with decreased PR enzyme levels was least affected in fluctuating light compared with wild type. Results for growth, photosynthesis and metabolites combined with thermodynamics-based flux analysis revealed two main causal factors for this unanticipated finding: reduced rates of photosynthesis in […]
Researchers discover new ultra strong material for microchip sensors
Phys.org November 2, 2023 Although there have been remarkable strides in achieving low-dissipation mechanical sensors by utilizing high tensile stress, the performance of even the best strategy is limited by the tensile fracture strength of the resonator materials. An international team of researchers (the Netherlands, USA – Brown University) found that a wafer-scale amorphous thin film of silicon carbide (SiC) material exhibited an ultimate tensile strength of over 10 GPa, reaching the regime reserved for strong crystalline materials and approaching levels experimentally shown in graphene nanoribbons. They fabricated amorphous SiC strings with high aspect ratios with mechanical modes exceeding quality […]
Scientists manipulate quantum fluids of light, bringing us closer to next-generation unconventional computing
Phys.org October 31, 2023 An international team of researchers (Russia, UK, Germany) investigated active spatial control of polariton condensates independent of the polariton, gain-inducing excitation profile by introducing an extra intracavity semiconductor layer, nonresonant to the cavity mode. Partial saturation of the optical absorption in the uncoupled layer enabled the ultrafast modulation of the effective refractive index and, through excited-state absorption, the polariton dissipation. Utilizing an intricate interplay of these mechanisms, they demonstrated control over the spatial profile, density, and energy of a polariton condensate at room temperature… read more. TECHNICAL ARTICLE
Scientists map loss of groundwater storage around the world
Phys.org November 6, 2023 Groundwater overdraft gives rise to multiple adverse impacts including land subsidence and permanent groundwater storage loss. Existing methods are unable to characterize groundwater storage loss at the global scale with sufficient resolution to be relevant for local studies. A team of researchers in the US (Colorado State University, Missouri University of Science and Technology, Desert Research Institute) explored the interrelation between groundwater stress, aquifer depletion, and land subsidence using remote sensing and model-based datasets with a machine learning approach. They developed a model which predicted global land subsidence magnitude at high spatial resolution (~2 km), provided a […]