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Quantum tunnelling

Quantum tunnelling
Quantum tunnelling or tunneling (see spelling differences) is the quantum mechanical phenomenon where a subatomic particle passes through a potential barrier. Quantum tunneling is not predicted by the laws of classical mechanics where surmounting a potential barrier requires enough potential energy. Quantum tunnelling plays an essential role in several physical phenomena, such as the nuclear fusion that occurs in main sequence stars like the Sun.[1] It has important applications in the tunnel diode,[2] quantum computing, and in the scanning tunnelling microscope. The effect was predicted in the early 20th century, and its acceptance as a general physical phenomenon came mid-century.[3] Fundamental quantum mechanical concepts are central to this phenomenon, which makes quantum tunnelling one of the novel implications of quantum mechanics. History[edit] After attending a seminar by Gamow, Max Born recognised the generality of tunnelling. Introduction to the concept[edit] Applications[edit] or Related:  spacetimeReference 2

Wave–particle duality Origin of theory[edit] The idea of duality originated in a debate over the nature of light and matter that dates back to the 17th century, when Christiaan Huygens and Isaac Newton proposed competing theories of light: light was thought either to consist of waves (Huygens) or of particles (Newton). Through the work of Max Planck, Albert Einstein, Louis de Broglie, Arthur Compton, Niels Bohr, and many others, current scientific theory holds that all particles also have a wave nature (and vice versa).[2] This phenomenon has been verified not only for elementary particles, but also for compound particles like atoms and even molecules. For macroscopic particles, because of their extremely short wavelengths, wave properties usually cannot be detected.[3] Brief history of wave and particle viewpoints[edit] Thomas Young's sketch of two-slit diffraction of waves, 1803 Particle impacts make visible the interference pattern of waves. A quantum particle is represented by a wave packet.

Company 3D prints ceramics that can withstand 1700ºC temps Ceramics have many useful properties: they can be extremely durable, and hold up to very high temperatures. Unfortunately simple flaws in the material can leave the door open for catastrophic failures, making manufacturing, especially of complex shapes, challenging. Now, a team at a company called HRL Laboratories has described a method of 3D printing ceramics. The work, which combines a number of techniques that have already been in use, can create complicated structures that are very robust and able to withstand temperatures of up to 1,700 degrees Celsius. The foundation of the work actually dates back to the 1960s. The result is smaller than the original polymer, but it retains the original's shape. The key step used in the new work is to replace the standard polymers used to create ceramics with a chemical that polymerizes when exposed to UV light. These setups use a bath of the building blocks of the polymer, and expose it to a precise pattern of UV light.

Uncertainty principle Introduced first in 1927, by the German physicist Werner Heisenberg, it states that the more precisely the position of some particle is determined, the less precisely its momentum can be known, and vice versa.[1] The formal inequality relating the standard deviation of position σx and the standard deviation of momentum σp was derived by Earle Hesse Kennard[2] later that year and by Hermann Weyl[3] in 1928: (ħ is the reduced Planck constant, h / 2π). Since the uncertainty principle is such a basic result in quantum mechanics, typical experiments in quantum mechanics routinely observe aspects of it. Introduction[edit] Click to see animation. The superposition of several plane waves to form a wave packet. As a fundamental constraint, higher level descriptions of the universe must supervene on quantum mechanical descriptions which includes Heisenberg's uncertainty relationship. Wave mechanics interpretation[edit] (Ref [9]) Main article: Wave packet . In the case of the single-moded plane wave, .

Water bears survive drying out by turning into glass Tardigrades, commonly known as water bears, are not particularly impressive creatures at first glance. They’re microscopic and don’t really figure into your daily life that much, but they’re notable for being nearly indestructible. You can freeze, boil, evaporate, and starve a Tardigrade, and it’ll just bounce right back when conditions improve. Now, scientists have identified an ingenious mechanism used by the water bear to survive drying — it basically turns to glass. When water becomes scarce, the water bear goes into hibernation mode with the intention of reviving itself when it can rehydrate. Researchers analyzing the Tardigrade genome have identified the so-called intrinsically disordered proteins (IDPs) that are responsible for the generation of bioglass. After identifying the gene sequences responsible, the team managed to engineer Tardigrades with lower levels of IDPs.

Introduction to quantum mechanics Many aspects of quantum mechanics are counterintuitive[3] and can seem paradoxical, because they describe behavior quite different from that seen at larger length scales. In the words of quantum physicist Richard Feynman, quantum mechanics deals with "nature as She is – absurd".[4] For example, the uncertainty principle of quantum mechanics means that the more closely one pins down one measurement (such as the position of a particle), the less accurate another measurement pertaining to the same particle (such as its momentum) must become. The first quantum theory: Max Planck and black-body radiation[edit] Hot metalwork. The yellow-orange glow is the visible part of the thermal radiation emitted due to the high temperature. Thermal radiation is electromagnetic radiation emitted from the surface of an object due to the object's internal energy. Predictions of the amount of thermal radiation of different frequencies emitted by a body. Photons: the quantisation of light[edit] show Spin[edit] .

A mathematician has proposed a way to create and manipulate gravity Yesterday, the physics community got hyped-up over rumours that scientists might have finally detected gravitational waves - ripples in the curvature of spacetime predicted by Einstein 100 years ago - and that their observations could be coming to a peer-reviewed journal near you soon. So far, our understanding of how gravity affects the Universe has been limited to observations of natural gravitational fields created by distant stars and planets. In fact, gravity is the last of the four fundamental forces that humans haven't figured out how to produce and control. But now André Füzfa, a mathematician at the University of Namur in Belgium, has published a paper proposing a device that could do just that - albeit in tiny doses. "Somehow, studying gravity is a contemplative activity: physicists restrict themselves to the study of natural, pre-existing, sources of gravitation," writes Füzfa in the paper.

Richard Feynman Feynman developed a widely used pictorial representation scheme for the mathematical expressions governing the behavior of subatomic particles, which later became known as Feynman diagrams. During his lifetime, Feynman became one of the best-known scientists in the world. In a 1999 poll of 130 leading physicists worldwide by the British journal Physics World he was ranked as one of the ten greatest physicists of all time.[1] He assisted in the development of the atomic bomb during World War II and became known to a wide public in the 1980s as a member of the Rogers Commission, the panel that investigated the Space Shuttle Challenger disaster. In addition to his work in theoretical physics, Feynman has been credited with pioneering the field of quantum computing, and introducing the concept of nanotechnology. Early life[edit] Like Albert Einstein and Edward Teller, Feynman was a late talker, and by his third birthday had yet to utter a single word. Education[edit] Manhattan Project[edit]

In a brain, dissolvable electronics monitor health and then vanish From the folds and crinkles of a living brain, a fleeting fleck of electronics smaller than a grain of rice can wirelessly relay critical health information and then gently fade away. The transient sensors, which can measure pressure, temperature, pH, motion, flow, and potentially specific biomolecules, stand to permanently improve patient care, researchers said. With a wireless, dissolving sensor, doctors could ditch the old versions that require tethering patients to medical equipment and performing invasive surgery to remove, which adds risks of infections and complications to already vulnerable patients. Though the first version, reported in Nature, was designed for the brain and tested in the noggins of living rats, the authors think the sensors could be used in many tissues and organs for a variety of patients—from car crash victims with brain injuries to people with diabetes. Essentially, the sensors are made of elements and minerals that we already eat and drink, Murphy said.

Gluon Gluons /ˈɡluːɒnz/ are elementary particles that act as the exchange particles (or gauge bosons) for the strong force between quarks, analogous to the exchange of photons in the electromagnetic force between two charged particles.[6] In technical terms, gluons are vector gauge bosons that mediate strong interactions of quarks in quantum chromodynamics (QCD). Gluons themselves carry the color charge of the strong interaction. Properties[edit] Diagram 1: e+e− -> Y(9.46) -> 3g Numerology of gluons[edit] Unlike the single photon of QED or the three W and Z bosons of the weak interaction, there are eight independent types of gluon in QCD. This may be difficult to understand intuitively. Color charge and superposition[edit] In quantum mechanics, the states of particles may be added according to the principle of superposition; that is, they may be in a "combined state" with a probability, if some particular quantity is measured, of giving several different outcomes. Color singlet states[edit] A.

5 Evil Plants We Should Probably Get Rid Of There's a reason nobody makes horror movies about plants. At worst, they can give you a little bit of an itchy rash or grow fruit that will poison you. (Hint: Try not eating random shit you come across in the woods.) But if you look hard enough, you'll find some completely real merchants of verdant death that would have actually made The Happening a little bit scary. #5. kafka4prez/Wiki Commons This devious plant has achieved something usually only reserved for B-list comic book supervillains: It's capable of commanding swarms of insects. An enzyme in the nectar changes the ants' physiology, making it impossible for them to digest any other kind of sugar. Danita Delimont/Gallo Images/Getty ImagesYup, that is exactly how we imagined the plant would look, minus the skull-shaped leaves. "But wait," you might be saying, if you know anything about ants and plants. Ryan Somma/Wiki Commons"Kinda getting a few mixed signals over here, sweetums." #4. Rainer Wunderlich/Wiki Commons #3.

Satyendra Nath Bose Satyendra Nath Bose, FRS[2] (1 January 1894 – 4 February 1974) was an Indian physicist specialising in mathematical physics. He is best known for his work on quantum mechanics in the early 1920s, providing the foundation for Bose–Einstein statistics and the theory of the Bose–Einstein condensate. A Fellow of the Royal Society, he was awarded India's second highest civilian award, the Padma Vibhushan in 1954 by the Government of India.[5][6] The class of particles that obey Bose–Einstein statistics, bosons, was named after Bose by Paul Dirac.[7][8] A self-taught scholar and a polyglot, he had a wide range of interests in varied fields including physics, mathematics, chemistry, biology, mineralogy, philosophy, arts, literature, and music. Early life[edit] Bose was born in Calcutta (now Kolkata), the eldest of seven children. After completing his MSc, Bose joined the University of Calcutta as a research scholar in 1916 and started his studies in the theory of relativity. Honours[edit]

This fully transparent solar cell could make every window and screen a power source (updated) Back in August 2014, researchers at Michigan State University created a fully transparent solar concentrator, which could turn any window or sheet of glass (like your smartphone’s screen) into a photovoltaic solar cell. Unlike other “transparent” solar cells that we’ve reported on in the past, this one really is transparent, as you can see in the photos throughout this story. According to Richard Lunt, who led the research at the time, the team was confident the transparent solar panels can be efficiently deployed in a wide range of settings, from “tall buildings with lots of windows or any kind of mobile device that demands high aesthetic quality like a phone or e-reader.” Now Ubiquitous Energy, an MIT startup we first reported on in 2013, is getting closer to bringing its transparent solar panels to market. Scientifically, a transparent solar panel is something of an oxymoron. If you look closely, you can see a couple of black strips along the edges of plastic block.

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