Does Google’s app really need to constantly reset all Windows network interfaces?
Malicious updates made to a ubiquitous tool were a few weeks away from going mainstream.
New research exposes vulnerability in HTTP/2 protocol! The CONTINUATION frame can be exploited for DoS attacks, warns security expert Bartek Nowotarsk.
Using an ultrafast technique, researchers shed light on how the hydrogen-bonded structure of water is reflected in its x-ray spectrum.
Stiffening a Spring Made of Light
Posted in futurism
Adding a nonlinear crystal to an optical spring can change the spring’s stiffness, a finding that could allow the use of such devices as gravitational-wave detectors.
A way to create single photons whose spatiotemporal shapes do not expand during propagation could limit information loss in future photonic quantum technologies.
When enjoying the sight of a rainbow, information loss might not be the first thing that comes to mind. Yet dispersion, the underlying process that makes different colors travel at different speeds, also hampers scientists’ control of light propagation—a crucial capability for future photonic quantum technologies. As they move, short laser pulses tend to lengthen through dispersion and widen and dim through diffraction. Together, these effects limit our ability to make light reach a target, although mitigation strategies have been developed for classical pulses and, recently, for quantum light. Now Jianmin Wang at the Southern University of Science and Technology in China and colleagues have realized a quantum source of single photons that are impervious to spreading out during propagation, potentially safeguarding against the loss of information encoded in the photons spatiotemporal shapes [1].
In 2007, physicists demonstrated light beams, known as Airy beams, whose spatial profiles make them resilient to spreading out [2, 3]. These profiles consist of a pattern of bright and dark lobes surrounding a central bright component, with each feature propagating along a parabolic trajectory. Recently, scientists created quantum Airy beams, which are technically challenging to realize [4, 5]. The goal of Wang and colleagues’ work was to extend this principle to the temporal domain, producing quantum Airy single photons that do not spread out in both space and time. Such quantum “light bullets” could offer exciting possibilities for quantum technologies, much like their classical counterparts did for applications in areas from plasma physics to optical trapping [3, 6].
Shape Matters in Self-Assembly
Posted in biological, materials
Many biological structures form through the self-assembly of molecular building blocks. A new theoretical study explores how the shape of these building blocks can affect the formation rate [1]. The simplified model shows that hexagonal blocks can form large structures much faster than triangular or square blocks. The results could help biologists explain cellular behavior, while also giving engineers inspiration for more efficient self-assembly designs.
Certain viruses and cellular structures are made from self-assembling pieces that can be characterized by geometrical shapes. For example, some types of bacteria host carboxysomes, which are icosahedral (20-face) compartments built up from self-assembling hexagonal and pentagonal subunits.
To investigate the role of shape, Florian Gartner and Erwin Frey from Ludwig Maximilian University of Munich simulated self-assembly of two-dimensional structures with three types of building blocks: triangles, squares, and hexagons. The model assumed that the blocks bind along their edges, but these interactions are reversible, meaning that the resulting structures can fall apart before growing very large. Gartner and Frey found that certain shapes were better than others at assembling into larger structures, as they tended to form intermediate structures with more bonds around each block. In particular, hexagonal blocks were the most efficient building material, forming 1000-piece structures at a rate that was 10,000 times faster than triangular blocks.