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Kibble–Zurek Mechanism
The Kibble–Zurek mechanism (KZM) describes the non-equilibrium dynamics and the formation of topological defects in a system which is driven through a continuous phase transition at finite rate. It is named after Tom W. B. Kibble, who pioneered the study of domain structure formation in the early universe, and Wojciech H. Zurek, who related the number of defects it creates to the critical exponents of the transition and to its rate—to how quickly the critical point is traversed. Basic idea Based on the formalism of spontaneous symmetry breaking, Tom Kibble developed the idea for the primordial fluctuations of a two-component scalar field like the Higgs field. If a two-component scalar field switches from the isotropic and homogeneous high-temperature phase to the symmetry-broken stage during cooling and expansion of the very early universe (shortly after Big Bang), the order parameter necessarily cannot be the same in regions which are not connected by causality. Regions ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Topological Defect
A topological soliton occurs when two adjoining structures or spaces are in some way "out of phase" with each other in ways that make a seamless transition between them impossible. One of the simplest and most commonplace examples of a topological soliton occurs in old-fashioned coiled telephone handset cords, which are usually coiled clockwise. Years of picking up the handset can end up coiling parts of the cord in the opposite counterclockwise direction, and when this happens there will be a distinctive larger loop that separates the two directions of coiling. This odd looking transition loop, which is neither clockwise nor counterclockwise, is an excellent example of a topological soliton. No matter how complex the context, anything that qualifies as a topological soliton must at some level exhibit this same simple issue of reconciliation seen in the twisted phone cord example. Topological solitons arise with ease when creating the crystalline semiconductors used in modern elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Event Horizon
In astrophysics, an event horizon is a boundary beyond which events cannot affect an observer. Wolfgang Rindler coined the term in the 1950s. In 1784, John Michell proposed that gravity can be strong enough in the vicinity of massive compact objects that even light cannot escape. At that time, the Newtonian theory of gravitation and the so-called corpuscular theory of light were dominant. In these theories, if the escape velocity of the gravitational influence of a massive object exceeds the speed of light, then light originating inside or from it can escape temporarily but will return. In 1958, David Finkelstein used general relativity to introduce a stricter definition of a local black hole event horizon as a boundary beyond which events of any kind cannot affect an outside observer, leading to information and firewall paradoxes, encouraging the re-examination of the concept of local event horizons and the notion of black holes. Several theories were subsequently developed, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kibble Zurek Scaling
Kibble may refer to: * Dry compound feed, especially when used as dog food or cat food * chalk and flint rubble, also known as kibble in East Devon, used to consolidate ground * a large bucket, as used to raise ore from a mine shaft, see shaft mining * a rock of crack cocaine * kibbled wheat, a type of coarsely milled flour People * Brendan Kibble (born 1963), Australian musician * Bryan Kibble (1938–2016), British physicist and metrologist who invented the Kibble balance for measuring mass * Chris Kibble (born 1963), British jazz musician * George Kibble (1865–1923), English cricketer * Jack Kibble (''John Westly Kibble''; 1892–1969), American baseball player * Karima Kibble (née Trotter; born 1974), American Gospel singer * Nita Kibble (1879–1964), Australian librarian * Tom W. B. Kibble (1932–2016), British theoretical physicist, interests included quantum field theory and topological defects * Graham Kibble-White, British writer Other uses * Kibble Pal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KZM Exponential Divergence
KZM was an early radio broadcasting station, initially licensed to Preston D. Allen in Oakland, California. It was issued its first license in December 1921, moved to nearby Hayward, California in 1928, and was deleted in mid-1931. History 6XAJ Although KZM was first licensed as a broadcasting station in December 1921, this was actually a relicensing and continuation of operations begun under an Experimental license, 6XAJ, issued to the Preston D. Allen a few months earlier. Allen, described at the time as a "'thoroughbred' radio man in every respects", had extensive radio experience as an amateur operator as well as a radio technician during World War One."Hotel Oakland Has Radio Telephone" ''Pacific Radio News'', October 1921, page 97. He installed 6XAJ atop the Hotel Oakland as an adjunct to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Critical Exponent
Critical or Critically may refer to: *Critical, or critical but stable, medical states **Critical, or intensive care medicine * Critical juncture, a discontinuous change studied in the social sciences. * Critical Software, a company specializing in mission and business critical information systems *Critical theory, a school of thought that critiques society and culture by applying knowledge from the social sciences and the humanities * Critically endangered, a risk status for wild species * Criticality (status), the condition of sustaining a nuclear chain reaction Art, entertainment, and media * ''Critical'' (novel), a medical thriller written by Robin Cook * ''Critical'' (TV series), a Sky 1 TV series * "Critical" (''Person of Interest''), an episode of the American television drama series ''Person of Interest'' *"Critical", a 1999 single by Zion I People *Cr1TiKaL (born 1994), an American YouTuber and Twitch streamer See also *Critic * Criticality (other) *Critical Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relaxation Time
In the physical sciences, relaxation usually means the return of a perturbed system into equilibrium. Each relaxation process can be categorized by a relaxation time τ. The simplest theoretical description of relaxation as function of time ''t'' is an exponential law (exponential decay). In simple linear systems Mechanics: Damped unforced oscillator Let the homogeneous differential equation: :m\frac+\gamma\frac+ky=0 model damped unforced oscillations of a weight on a spring. The displacement will then be of the form y(t) = A e^ \cos(\mu t - \delta). The constant T (=2m/\gamma) is called the relaxation time of the system and the constant μ is the quasi-frequency. Electronics: RC circuit In an RC circuit containing a charged capacitor and a resistor, the voltage decays exponentially: : V(t)=V_0 e^ \ , The constant \tau = RC\ is called the ''relaxation time'' or RC time constant of the circuit. A nonlinear oscillator circuit which generates a repeating waveform by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Critical Phenomena
In physics, critical phenomena is the collective name associated with the physics of critical points. Most of them stem from the divergence of the correlation length, but also the dynamics slows down. Critical phenomena include scaling relations among different quantities, power-law divergences of some quantities (such as the magnetic susceptibility in the ferromagnetic phase transition) described by critical exponents, universality, fractal behaviour, and ergodicity breaking. Critical phenomena take place in second order phase transitions, although not exclusively. The critical behavior is usually different from the mean-field approximation which is valid away from the phase transition, since the latter neglects correlations, which become increasingly important as the system approaches the critical point where the correlation length diverges. Many properties of the critical behavior of a system can be derived in the framework of the renormalization group. In order to ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Complex Number
In mathematics, a complex number is an element of a number system that extends the real numbers with a specific element denoted , called the imaginary unit and satisfying the equation i^= -1; every complex number can be expressed in the form a + bi, where and are real numbers. Because no real number satisfies the above equation, was called an imaginary number by René Descartes. For the complex number a+bi, is called the , and is called the . The set of complex numbers is denoted by either of the symbols \mathbb C or . Despite the historical nomenclature "imaginary", complex numbers are regarded in the mathematical sciences as just as "real" as the real numbers and are fundamental in many aspects of the scientific description of the natural world. Complex numbers allow solutions to all polynomial equations, even those that have no solutions in real numbers. More precisely, the fundamental theorem of algebra asserts that every non-constant polynomial equation with re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wave Function
A wave function in quantum physics is a mathematical description of the quantum state of an isolated quantum system. The wave function is a complex-valued probability amplitude, and the probabilities for the possible results of measurements made on the system can be derived from it. The most common symbols for a wave function are the Greek letters and (lower-case and capital psi, respectively). The wave function is a function of the degrees of freedom corresponding to some maximal set of commuting observables. Once such a representation is chosen, the wave function can be derived from the quantum state. For a given system, the choice of which commuting degrees of freedom to use is not unique, and correspondingly the domain of the wave function is also not unique. For instance, it may be taken to be a function of all the position coordinates of the particles over position space, or the momenta of all the particles over momentum space; the two are related by a Fourier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superfluid Helium-4
Superfluid helium-4 is the superfluid form of helium-4, an isotope of the element helium. A superfluid is a state of matter in which matter behaves like a fluid with zero viscosity. The substance, which looks like a normal liquid, flows without friction past any surface, which allows it to continue to circulate over obstructions and through pores in containers which hold it, subject only to its own inertia. The formation of the superfluid is known to be related to the formation of a Bose–Einstein condensate. This is made obvious by the fact that superfluidity occurs in liquid helium-4 at far higher temperatures than it does in helium-3. Each atom of helium-4 is a boson particle, by virtue of its zero spin. Helium-3, however, is a fermion particle, which can form bosons only by pairing with itself at much lower temperatures, in a process similar to the electron pairing in superconductivity. History Known as a major facet in the study of quantum hydrodynamics and macroscopic qu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helium
Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling and melting point are the lowest among all the elements. It is the second lightest and second most abundant element in the observable universe (hydrogen is the lightest and most abundant). It is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this in both the Sun and in Jupiter, due to the very high nuclear binding energy (per nucleon) of helium-4, with respect to the next three elements after helium. This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay. The most common isotope of helium in the universe is helium-4, the vast majority of which was formed during t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KZM Algebraic Divergence
KZM was an early radio broadcasting station, initially licensed to Preston D. Allen in Oakland, California. It was issued its first license in December 1921, moved to nearby Hayward, California in 1928, and was deleted in mid-1931. History 6XAJ Although KZM was first licensed as a broadcasting station in December 1921, this was actually a relicensing and continuation of operations begun under an Experimental license, 6XAJ, issued to the Preston D. Allen a few months earlier. Allen, described at the time as a "'thoroughbred' radio man in every respects", had extensive radio experience as an amateur operator as well as a radio technician during World War One."Hotel Oakland Has Radio Telephone" ''Pacific Radio News'', October 1921, page 97. He installed 6XAJ atop the Hotel Oakland as an adjunct to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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