Circa 2020
What are the fundamental laws that govern our universe? How did the matter in the universe today get there? What exactly is dark matter?
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When we think about singularities, we tend to think of massive black holes in faraway galaxies or a distant future with runaway AI, but singularities are all around us. Singularities are simply a place where certain parameters are undefined. The North and South Pole, for example, are what’s known as coordinate singularities because they don’t have a defined longitude.
Optical singularities typically occur when the phase of light with a specific wavelength, or color, is undefined. These regions appear completely dark. Today, some optical singularities, including optical vortices, are being explored for use in optical communications and particle manipulation but scientists are just beginning to understand the potential of these systems. The question remains—can we harness darkness like we harnessed light to build powerful, new technologies?
Now, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed a new way to control and shape optical singularities. The technique can be used to engineer singularities of many shapes, far beyond simple curved or straight lines. To demonstrate their technique, the researchers created a singularity sheet in the shape of a heart.
“You can also engineer dead zones in radio waves or silent zones in acoustic waves,” said Lim. “This research points to the possibility of designing complex topologies in wave physics beyond optics, from electron beams to acoustics.”
When we think about singularities, we tend to think of massive black holes in faraway galaxies or a distant future with runaway AI, but singularities are all around us. Singularities are simply a place where certain parameters are undefined. The North and South Pole, for example, are what’s known as coordinate singularities because they don’t have a defined longitude.
Optical singularities typically occur when the phase of light with a specific wavelength, or color, is undefined. These regions appear completely dark. Today, some optical singularities, including optical vortices, are being explored for use in optical communications and particle manipulation but scientists are just beginning to understand the potential of these systems. The question remains — can we harness darkness like we harnessed light to build powerful, new technologies?
The Sverdrup Basin was a Carboniferous to Paleogene depocenter that accumulated over 12 km of sediment from Carboniferous to Paleogene time18 (Fig. 1). From Late Carboniferous to Early Triassic time, the Sverdrup Basin was along the NW margin of Pangea at palaeolatitudes of 35–40°N (ref. 19) (Fig. 1). Until the EPME, the basin was characterised by a central deep basinal area of fine-grained clastic deposition surrounded by a shallow shelf dominated by biogenic carbonate that transitioned in the late Permian to chert formed by shallow water siliceous sponges19. After the EPME, the Sverdrup basin was dominated by clastic-dominated sedimentation18. In this study, we examined the distal deep-water Buchanan Lake section which preserves outstanding Boreal records of the EPME, followed by the biotic recovery in the Early Triassic5. The Buchanan Lake section consists mostly of black shale of the Late Permian Black Stripe Formation and overlying Early Triassic Blind Fiord Formation that preserves characteristic post-extinction fauna20 (Fig. 2).
During the last decade, the Buchanan Lake section has been extensively examined, and the carbon isotope chemostratigraphy, elemental compositions of the shale, and oceanic palaeo-redox changes have been well constrained5, 11, 19, 20, 21, 22, 23, 24, 25, 26 (Fig. 2). The EPME in the Sverdrup Basin is marked by eradication of silica and carbonate producers along with the onset of a significant negative δ13 Corg shift that has been correlated globally with the dated Global Stratotype Section and Point (GSSP) for the Permian-Triassic boundary at Meishan, China, at ~251.9 Ma (refs. 3, 4, 20, 27, 28) (Fig. 2). The palaeo-redox conditions during the deposition of the Late Permian Black Stripe Formation and Early Triassic Blind Fiord Formation evolved from an oxic water column with a strong redoxcline in the sediments to anoxic and then to sulphidic bottom water conditions (Fig. 2).
Scientists from the Division of Physics at the University of Tsukuba used the quantum effect called ‘spin-locking’ to significantly enhance the resolution when performing radio-frequency imaging of nitrogen-vacancy defects in diamond. This work may lead to faster and more accurate material analysis, as well as a path towards practical quantum computers.
Nitrogen-vacancy (NV) centers have long been studied for their potential use in quantum computers. A NV center is a type of defect in the lattice of a diamond, in which two adjacent carbon atoms have been replaced with a nitrogen atom and a void. This leaves an unpaired electron, which can be detected using radio-frequency waves, because its probability of emitting a photon depends on its spin state. However, the spatial resolution of radio wave detection using conventional radio-frequency techniques has remained less than optimal.
Now, researchers at the University of Tsukuba have pushed the resolution to its limit by employing a technique called ‘spin-locking’. Microwave pulses are used to put the electron’s spin in a quantum superposition of up and down simultaneously. Then, a driving electromagnetic field causes the direction of the spin to precess around, like a wobbling top. The end result is an electron spin that is shielded from random noise but strongly coupled to the detection equipment. “Spin-locking ensures high accuracy and sensitivity of the electromagnetic field imaging,” first author Professor Shintaro Nomura explains. Due to the high density of NV centers in the diamond samples used, the collective signal they produced could be easily picked up with this method. This permitted the sensing of collections of NV centers at the micrometer scale.
😀 2011
Trevor D. Rhone, Dwipesh Majumder, Brian S. Dennis, Cyrus Hirjibehedin, Irene Dujovne, Javier G. Groshaus, Yann Gallais, Jainendra K. Jain, Sudhansu S. Mandal, Aron Pinczuk, Loren Pfeiffer, and Ken West. 2011. “Higher-Energy Composite Fermion Levels in the Fractional Quantum Hall Effect.” Phys. Rev. Lett., 106, Pp. 096803.
In 2015, after 85 years of searching, researchers confirmed the existence of a massless particle called the Weyl fermion. With the unique ability to behave as both matter and anti-matter inside a crystal, this quasiparticle is like an electron with no mass. The story begun in 1928 when Dirac proposed an equation for the foundational unification of quantum mechanics and special relativity in describing the nature of the electron. This new equation suggested three distinct forms of relativistic particles: the Dirac, the Majorana, and the Weyl fermions. And recently, an analog of Weyl fermions has been discovered in certain electronic materials exhibiting a strong spin orbit coupling and topological behavior. Just as Dirac fermions emerge as signatures of topological insulators, in certain types of semimetals, electrons can behave like Weyl fermions.
These Weyl fermions are what can be called quasiparticles, which means they can only exist in a solid such as a crystal, and not as standalone particles. However, as complex as quasiparticles sound, their behavior is actually much simpler than that of fundamental particles, because their properties allow them to shrug off the same forces that knock their counterparts around. This discovery of Weyl fermions is huge, not just because there is finally a proof that these elusive particles exist, but because it paves the way for far more efficient electronics, and new types of quantum computing. Weyl fermions could be used to solve the traffic jams with electrons in electronics. In fact, Weyl electrons can carry charges at least 1000 times faster than electrons in ordinary semiconductors, and twice as fast as inside graphene. This could lead to a whole new type of electronics called ‘Weyltronics’.
Scientists have succeeded in combining two exciting material types together for the very first time: an ultrathin semiconductor just a single atom thick; and a superconductor, capable of conducting electricity with zero resistance.
Both these materials have unusual and fascinating properties, and by putting them together through a delicate lab fabrication process, the team behind the research is hoping to open up all kinds of new applications in classical and quantum physics.
Semiconductors are key to the electrical gadgets that dominate our lives, from TVs to phones. What makes them so useful as opposed to regular metals is their electrical conductivity can be adjusted by applying a voltage to them (among other methods), making it easy to switch a current flow on and off.
Data collected can be used to provide new insights into the evolution of the Kuiper Belt, and the larger solar system.
Trans-Neptunian Objects (TNOs), small objects that orbit the sun beyond Neptune, are fossils from the early days of the solar system which can tell us a lot about its formation and evolution.
A new study led by Mohamad Ali-Dib, a research scientist at the NYU Abu Dhabi Center for Astro, Particle, and Planetary Physics, reports the significant discovery that two groups of TNOs with different surface colors also have very different orbital patterns. This new information can be compared to models of the solar system to provide fresh insights into its early chemistry. Additionally, this discovery paves the way for further understanding of the formation of the Kuiper Belt itself, an area beyond Neptune comprised of icy objects, that is also the source of some comets.
