Spend weeks looking online and in books for a spell that could work for what you want and that you can actually get the ingredients for. Each time you find one that you like, but can’t possibly begin to even think about getting exotic materials for, you wonder if you’re really cut out for this (you are).
Read over the one you found a dozen times a day, Googling terms you don’t understand and only getting a vague explanation of on some sparkly New Age website that hasn’t been in use for years. Wonder again if you can really do this (you can).
Print out the spell when no one else is around, carefully holding it so that the text doesn’t show and rushing back to your room. Read over it again and again until the corners are bent and there are wrinkles where your fingers have been. Worry about not being able to memorize it.
In the middle of the night when no one is awake and you’re shaking because this is it wave your hand in a circle because you always see spells call for circles. Then you speak the words in something that is half whisper and half breath, so quiet no one could possibly hear it, but you still worry.
Finish the spell and find yourself caught between the thoughts of “Did I do it right?” and “Finally.”
This mosaic is believed to represent the god Tezcatlipoca, or ‘Smoking Mirror.’ One of four powerful creator deities, who were amongst the most important gods in the Mexica (Aztec) pantheon, Smoking Mirror images can be recognized by the distinctive black stripes across his face. The base for the mosaic is a human skull. Long deerskin straps would have allowed the skull to be worn as part of priestly regalia, and deerskin strips connected the jaw while allowing it to open and close. The turquoise, lignite, pyrite and shell were all procured from the farthest reaches of the Mexica empire or through trade with far-flung peoples. The effort made in assembling this diverse selection of exotic materials emphasizes the divine ‘other-worldly’ nature both of the mosaic and whoever possessed it.
As protector of potential plague victims and soldiers, Saint Sebastian (died ca. 288) was popular with the faithful. The emphasis is on the saint’s God-given beauty and the exotic material to realize it. The Pretorian is shown shot through with the arrows of his martyrdom. Tears trickle from his eyes as he appears to breathe a last sigh of exhaustion, provoking compassion. A putto is about to crown the martyr with a winner’s laurel wreath, thus vanquishing his physical suffering. The distinctive style of the so-called Master of the Furies is supremely present and similarly found in the master’s name-piece, a Fury statuette in the Kunsthistorisches Museum in Vienna.
Carlo Bugatti’s work represents one of Art Nouveau’s most eccentric variations. Highly innovative in almost every respect, Bugatti’s work made use of unusual materials, primarily exotic woods, vellum, parchment, and nacre, to create very unique, unmistakable work that seem at times more meant to be appreciated as sculpture than actually used. Apart from making chairs, cabinets, desks, and tables, he also produced a limited amount of silver, textile, and ceramic work, as well as musical instruments, screens, mirrors, and wall decors for his most fully-designed interiors. His work falls in primarily two unique phases and styles: the first occuring from the late 1880s until around 1900, and the other from 1900 until he stopped producing furniture in 1918. The two styles have many similarities, but are also highly distinctive.
The first phase of his design is dominated by a certain interest in exoticism. His works of this time draw heavily from Moresque, Arabic, and Japanese design, which he synthesized in a very modern version of Orientalism. His design of this period is dominated by strongly geometric furniture covered with decoration evoking Japanese screens, Islamic geometric patterns, and text resembling kanji and kufic script. Ogee arches, spires, columns, jagged edges, and tassels are common decorations of his furniture at this time. Dark wood predominate and define the strongly sculptural forms, while painted vellum or mother-of-pearl inlays provide most of the decoration. His furniture of this time is also defined by a predilection for asymmetry, though this is not always the case.
The second phase of his work is defined by his four interiors done for the Turin exhibition. Here his work becomes even more sculptural and geometric, but rather than favoring the rectangle, his work becomes more and more curved. Vellum becomes the main material, with whole pieces in furniture completely covered with it. The exotic imagery become less pronounced and are replaced by highly geometric insect and bird motifs. It is perhaps these works that are the most obviously Art Nouveau of his work, with the surplus of curves and insect motifs. However, they maintain a highly unique character, their subdued, pastel decoration and large expanses of off-white color having a very modern feel that predicts the predominantly single color furniture of the International Style.
Bugatti’s style was always unique even from other Italian designers, who tended generally either to imitate the floral style of French Art Nouveau designers, follow in Renaissance and Islamic Revival styles, or design works that looked forward to the heavily angular machine aesthetic of the Futurists. Bugatti seems to draw a little bit from all three traditions, but his work also seems to draw a bit from a love of primitive culture. His use of vellum, covered with pale decoration and cryptic pseudo-script, seem to remind one of old manuscripts and lost civilizations. His style is thus one highly suitable for the end of a century and beginning of a new one. It both looks back to the styles before it while feeling very strongly like the first breath of an entirely new one.
Physicists predict novel phenomena in exotic materials
Better understanding of topological semimetals could help usher in future electronics
Discovered just five years ago, topological semimetals are materials with unusual physical properties that could make them useful for future electronics.
In the latest issue of Nature Physics, MIT researchers report a new theoretical characterization of topological semimetals’ electrical properties that accurately describes all known topological semimetals and predicts several new ones.
Guided by their model, the researchers also describe the chemical formula and crystal structure of a new topological semimetal that, they reason, should exhibit electrical characteristics never seen before.
“Generally, the properties of a material are sensitive to many external perturbations,” says Liang Fu, an assistant professor of physics at MIT and senior author on the new paper.
“What’s special about these topological materials is they have some very robust properties that are insensitive to these perturbations. That’s attractive because it makes theory very powerful in predicting materials, which is rare in condensed-matter physics. Here, we know how to distill or extract the most essential properties, these topological properties, so our methods can be approximate, but our results will be exact.”
Semimetals are somewhat like semiconductors, which are at the core of all modern electronics. Electrons in a semiconductor can be in either the “valence band,” in which they’re attached to particular atoms, or the “conduction band,” in which they’re free to flow through the material as an electrical current. Switching between conductive and nonconductive states is what enables semiconductors to instantiate the logic of binary computation.
Bumping an electron from the valence band into the conduction band requires energy, and the energy differential between the two bands is known as the “band gap.” In a semimetal – such as the much-studied carbon sheets known as graphene – the band gap is zero. In principle, that means that semimetal transistors could switch faster, at lower powers, than semiconductor transistors do.
The term “topological” is a little more oblique. Topology is a branch of mathematics that treats geometry at a high level of abstraction. Topologically, any object with one hole in it – a coffee cup, a donut, a garden hose – is equivalent to any other. But no amount of deformation can turn a donut into an object with two holes, or none, so two-holed and no-holed objects constitute their own topological classes.
In a topological semimetal, “topological” doesn’t describe the geometry of the material itself; it describes the graph of the relationship between the energy and the momentum of electrons in the material’s surface. Physical perturbations of the material can warp that graph, in the same sense that a donut can be warped into a garden hose, but the material’s electrical properties will remain the same. That’s what Fu means when he says, “Our methods can be approximate, but our results will be exact.”
Fu and his colleagues – joint first authors Chen Fang and Ling Lu, both of whom were MIT postdocs and are now associate professors at the Institute of Physics in Beijing; and Junwei Liu, a postdoc at MIT’s Materials Processing Center – showed that the momentum-energy relationships of electrons in the surface of a topological semimetal can be described using mathematical constructs called Riemann surfaces.
Widely used in the branch of math known as complex analysis, which deals with functions that involve the square root of -1, or i, Riemann surfaces are graphs that tend to look like flat planes twisted into spirals.
“What makes a Riemann surface special is that it’s like a parking-garage graph,” Fu says. “In a parking garage, if you go around in a circle, you end up one floor up or one floor down. This is exactly what happens for the surface states of topological semimetals. If you move around in momentum space, you find that the energy increases, so there’s this winding.”
The researchers showed that a certain class of Riemann surfaces accurately described the momentum-energy relationship in known topological semimetals. But the class also included surfaces that corresponded to electrical characteristics not previously seen in nature.
The momentum-energy graph of electrons in the surface of a topological semimetal is three dimensional: two dimensions for momentum, one dimension for energy. If you take a two-dimensional cross section of the graph – equivalent to holding the energy constant – you get all the possible momenta that electrons can have at that energy. The graph of those momenta consists of curves, known as Fermi arcs.
The researchers’ model predicted topological semimetals in which the ends of two Fermi arcs would join at an angle or cross each other in a way that was previously unseen. Through a combination of intuition and simulation, Fang and Liu identified a material – a combination of strontium, indium, calcium, and oxygen – that, according to their theory, should exhibit such exotic Fermi arcs.
What uses, if any, these Fermi arcs may have is not clear. But topographical semimetals have such tantalizing electrical properties that they’re worth understanding better.
Of his group’s new work, however, Fu acknowledges that for him, “the appeal is its mathematical beauty – and the fact that this mathematical beauty can be found in real materials.”
The 19th century was the era of the import. China began mass-producing items specifically to be sold on the Western market. One of the most popular of these items was fans. The fans were often intricate and fanciful, and make out of exotic materials like ivory, feathers, and tortoiseshell.