Phys.org February 14, 2024 Nonsignaling boxes (NS) are theoretical resources defined by the principle of no-faster-than-light communication. They generalize quantum correlations and some of them are known to collapse communication complexity (CC). However, this collapse is strongly believed to be unachievable in nature. An international team of researchers (France, Canada) provided intuition on which theories are unrealistic. They found a better sufficient condition for a nonlocal box to collapse CC, thus extended the known collapsing region. In some slices of NS, they showed that this condition coincides with an area outside of an ellipse… read more. TECHNICAL ARTICLE Full […]
Detecting atmospheric rivers with satellite observations
Phys.org February 19, 2024 Atmospheric rivers (ARs) are filaments of enhanced horizontal moisture transport in the atmosphere. They play a prominent role in the meridional moisture transport and regional weather extremes. But the representations of ARs and their associated precipitation on a global scale remains largely unknown. A team of researchers in the US (UCLA, NCAR, Caltech) developed an AR detection algorithm specifically for satellite observations using moisture and the geostrophic winds derived from 3D geopotential height field from the combined retrievals of the Atmospheric Infrared Sounder and the Advanced Microwave Sounding Unit on NASA Aqua satellite. The algorithm enabled […]
A new design for quantum computers
Science Daily February 15, 2024 Arrays of Rydberg atoms are suitable to study quantum phase transitions in one dimension. Theoretically predicted chiral transition out of period-four phase is still pending experimental verification mainly due to extremely short interval over which this transition is realized in a single-component Rydberg array. Researchers in the Netherlands showed that multicomponent Rydberg arrays with extra experimentally tunable parameters provided a mechanism to manipulate quantum critical properties without breaking translation symmetry explicitly. They considered an effective blockade model of two component Rydberg atoms. Weak and strong components obeyed nearest- and next-nearest-neighbor blockades correspondingly. When laser detuning […]
A new record for atom-based quantum computers: 1,000 atomic qubits and rising
Phys.org February 15, 2024 Researchers in Germany designed a large-scale quantum-processing architecture surpassing the tier of 1000 atomic qubits. By tiling multiple microlens-generated tweezer arrays, each operated by an independent laser source, they eliminated laser-power limitations in the number of allocatable qubits. With two separate arrays, they implemented combined 2D configurations of 3000 qubit sites with a mean number of 1167(46) single-atom quantum systems. The transfer of atoms between the two arrays effectively. Supercharging one array designated as the quantum processing unit with atoms from the secondary array significantly increased the number of qubits and the initial filling fraction. They […]
Physicists develop new solar cell design for better efficiency
Phys.org February 20, 2024 Photovoltaics offers a large potential for the supply of clean and renewable energy. Silicon solar cells used for this purpose have efficiency limits. One reason for this is that some of the energy from short-wave radiation is not converted into electricity, but into unwanted heat. Through computer simulation researchers in Germany showed that to increase the efficiency, the silicon solar cell could be provided with an organic layer, for example made from the semiconductor tetracene. Short-wave light is absorbed in this layer and converted into high-energy excitons. These excitons decay in the tetracene into two low-energy […]
Quantum dark states lead to an advantage in noise reduction
Phys.org February 19, 2024 Researchers at the University of Colorado described a method to create and store scalable and long-lived entangled spin-squeezed states within a manifold of many-body cavity dark states using collective emission of light from multilevel atoms inside an optical cavity. They showed that the system could be tuned to generate squeezing in a dark state where it will be immune to super radiance. More generically that squeezing could be generated using a combination of super radiance and coherent driving in a bright state, and subsequently transferred via single-particle rotations to a dark state where squeezing could be […]
Researchers achieve breakthrough in silicon-compatible magnetic whirls
Phys.org February 20, 2024 Antiferromagnets hosting real-space topological textures are promising platforms to model fundamental ultrafast phenomena and explore spintronics. However, as they are epitaxially fabricated on specific symmetry-matched substrates, preserving their intrinsic magneto-crystalline order, curtails their integration with dissimilar supports, restricting the scope of fundamental and applied investigations. An international team of researchers (UK, Switzerland, Singapore) circumvented this limitation by designing detachable crystalline antiferromagnetic nanomembranes of α-Fe2O3. They showed that flat nanomembranes host a spin-reorientation transition and rich topological phenomenology. They demonstrated the reconfiguration of antiferromagnetic states across three-dimensional membrane folds resulting from flexure-induced strains. They combined these developments […]
Researchers develop world’s most efficient quantum dot solar cell
Nanowerk February 21, 2024 Research has predominantly focused on inorganic cation perovskite-based colloidal quantum dots (PQDs) even though organic cation PQDs have more favorable bandgaps. Researchers in South Korea developed solar cells using narrow bandgap organic cation based PQDs and demonstrated substantially higher efficiency compared with their inorganic counterparts. They employed an alkyl ammonium iodide-based ligand exchange strategy, which proved to be substantially more efficient in replacing the long-chain oleyl ligands than conventional methyl acetate-based ligand exchange while stabilizing the α phase of organic PQDs in ambient conditions. They showed a solar cell with the organic cation PQDs with high […]
‘Scientists’ warning’ on climate and technology
Science Daily February 15, 2024 Current technological systems are exacerbating climate change and the wholesale conversion of the Earth’s ecosystems. Adopting new technologies, such as clean energy technologies and artificial intelligence, may be necessary for addressing these crises. Such transformation is not without risks, but it may help set human civilizations on a path to a sustainable future. An international team of researchers (USA – UC Irvine, University of Kansas, Oregon State University, MIT, New Zealand) provided an integrative review of approaches that scholars and practitioners have taken in enacting technological change, and provide a framework for how these approaches […]
Surface to Air Missiles Are Too Slow and Weak To Catch SpaceX Starship
Next Big Future February 19, 2024 A SpaceX Starship will be much harder to shootdown than an ICBM. It is like an ICBM with massive course change capabilities. A SAM-5 surface to air missile is a larger missile with a top speed of Mach 4 and reaches an altitude up to 19 miles. Passenger airplanes have a cruising altitude of 33,000 to 40,000 feet (6-8 miles). The Russian S-200 SAM has a maximum altitude of 180,000 feet (55 km or 34 miles). It is generally expected that it will take four interceptors to have high probability of taking out an […]