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Fractional Vortices
In a standard superconductor, described by a complex field fermionic condensate wave function (denoted , \Psi, e^), vortices carry quantized magnetic fields because the condensate wave function , \Psi, e^ is invariant to increments of the phase \phi by 2\pi. There a winding of the phase by 2\pi creates a vortex which carries one flux quantum. See quantum vortex. The term Fractional vortex is used for two kinds of very different quantum vortices which occur when: (i) A physical system allows phase windings different from 2\pi \times \mathit, i.e. non-integer or fractional phase winding. Quantum mechanics prohibits it in a uniform ordinary superconductor, but it becomes possible in an inhomogeneous system, for example, if a vortex is placed on a boundary between two superconductors which are connected only by an extremely weak link (also called a Josephson junction); such a situation also occurs in some cases in polycrystalline samples on grain boundaries etc. At such superconduc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semifluxon
In superconductivity, a semifluxon is a half integer vortex of supercurrent carrying the magnetic flux equal to the half of the magnetic flux quantum . Semifluxons exist in the 0-π long Josephson junctions at the boundary between 0 and π regions. This 0-π boundary creates a π discontinuity of the Josephson phase. The junction reacts to this discontinuity by creating a semifluxon. Vortex's supercurrent circulates around 0-π boundary. In addition to semifluxon, there exist also an antisemifluxon. It carries the flux and its supercurrent circulates in the opposite direction. Mathematically, a semifluxon can be constructed by joining two tails of conventional (integer) fluxon (kink of the sine-Gordon equation) at the 0-π boundary. Semifluxon is a particular example of the ''fractional vortex pinned at the phase discontinuity'', see Fractional vortices for details. For the first time the semifluxons were observed at the tricrystal grain boundaries in d-wave superconductors and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2019 ''Journal Citation Reports'' (with an ascribed impact factor of 42.778), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in autumn 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander Macmillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the journal; ''Nature'' redoubled its efforts in exp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Applied Physics Letters
''Applied Physics Letters'' is a weekly peer-reviewed scientific journal that is published by the American Institute of Physics. Its focus is rapid publication and dissemination of new experimental and theoretical papers regarding applications of physics in all disciplines of science, engineering, and modern technology. Additionally, there is an emphasis on fundamental and new developments which lay the groundwork for fields that are rapidly evolving.Home page Applied Physics Letters. American Institute of Physics. 2016.Overview Applied Physics Letters. American Institute of Physics. 2016. The journal was established in 1962. The |
Superconductivity
Superconductivity is a set of physical properties observed in certain materials where electrical resistance vanishes and magnetic fields are expelled from the material. Any material exhibiting these properties is a superconductor. Unlike an ordinary metallic conductor, whose resistance decreases gradually as its temperature is lowered, even down to near absolute zero, a superconductor has a characteristic critical temperature below which the resistance drops abruptly to zero. An electric current through a loop of superconducting wire can persist indefinitely with no power source. The superconductivity phenomenon was discovered in 1911 by Dutch physicist Heike Kamerlingh Onnes. Like ferromagnetism and atomic spectral lines, superconductivity is a phenomenon which can only be explained by quantum mechanics. It is characterized by the Meissner effect, the complete cancelation of the magnetic field in the interior of the superconductor during its transitions into the superconduct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Review B
''Physical Review B: Condensed Matter and Materials Physics'' (also known as PRB) is a peer-reviewed, scientific journal, published by the American Physical Society (APS). The Editor of PRB is Laurens W. Molenkamp. It is part of the ''Physical Review'' family of journals. About the Physical Review Journals The current Editor in Chief is . PRB currently publishes over 4500 papers a year, making it one of the largest physics journals in the world. PRB ranked by the Eigenfactor, University of Washingto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Review Letters
''Physical Review Letters'' (''PRL''), established in 1958, is a peer-reviewed, scientific journal that is published 52 times per year by the American Physical Society. As also confirmed by various measurement standards, which include the ''Journal Citation Reports'' impact factor and the journal ''h''-index proposed by Google Scholar, many physicists and other scientists consider ''Physical Review Letters'' to be one of the most prestigious journals in the field of physics. ''According to Google Scholar, PRL is the journal with the 9th journal h-index among all scientific journals'' ''PRL'' is published as a print journal, and is in electronic format, online and CD-ROM. Its focus is rapid dissemination of significant, or notable, results of fundamental research on all topics related to all fields of physics. This is accomplished by rapid publication of short reports, called "Letters". Papers are published and available electronically one article at a time. When published in s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Vortex
In physics, a quantum vortex represents a quantized flux circulation of some physical quantity. In most cases, quantum vortices are a type of topological defect exhibited in superfluids and superconductors. The existence of quantum vortices was first predicted by Lars Onsager in 1949 in connection with superfluid helium. Onsager reasoned that quantisation of vorticity is a direct consequence of the existence of a superfluid order parameter as a spatially continuous wavefunction. Onsager also pointed out that quantum vortices describe the circulation of superfluid and conjectured that their excitations are responsible for superfluid phase transitions. These ideas of Onsager were further developed by Richard Feynman in 1955 and in 1957 were applied to describe the magnetic phase diagram of type-II superconductors by Alexei Alexeyevich Abrikosov. In 1935 Fritz London published a very closely related work on magnetic flux quantization in superconductors. London's fluxoid can also be vie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semifluxon
In superconductivity, a semifluxon is a half integer vortex of supercurrent carrying the magnetic flux equal to the half of the magnetic flux quantum . Semifluxons exist in the 0-π long Josephson junctions at the boundary between 0 and π regions. This 0-π boundary creates a π discontinuity of the Josephson phase. The junction reacts to this discontinuity by creating a semifluxon. Vortex's supercurrent circulates around 0-π boundary. In addition to semifluxon, there exist also an antisemifluxon. It carries the flux and its supercurrent circulates in the opposite direction. Mathematically, a semifluxon can be constructed by joining two tails of conventional (integer) fluxon (kink of the sine-Gordon equation) at the 0-π boundary. Semifluxon is a particular example of the ''fractional vortex pinned at the phase discontinuity'', see Fractional vortices for details. For the first time the semifluxons were observed at the tricrystal grain boundaries in d-wave superconductors and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pi Josephson Junction
A Josephson junction is a quantum mechanical device which is made of two superconducting electrodes separated by a barrier (thin insulating tunnel barrier, normal metal, semiconductor, ferromagnet, etc.). A Josephson junction is a Josephson junction in which the Josephson phase ''φ'' equals in the ground state, i.e. when no external current or magnetic field is applied. Background The supercurrent ''I''''s'' through a Josephson junction (JJ) is generally given by ''I''''s'' = ''I''''c''sin(''φ''), where φ is the phase difference of the superconducting wave functions of the two electrodes, i.e. the Josephson phase. The critical current ''I''''c'' is the maximum supercurrent that can exist through the Josephson junction. In experiment, one usually causes some current through the Josephson junction and the junction reacts by changing the Josephson phase. From the above formula it is clear that the phase ''φ'' = arcsin(''I''/''I''''c''), where ''I'' is the applied (super)curr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abrikosov Vortex
In superconductivity, fluxon (also called a Abrikosov vortex and quantum vortex) is a vortex of supercurrent in a type-II superconductor, used by Alexei Abrikosov to explain magnetic behavior of type-II superconductors. Abrikosov vortices occur generically in the Ginzburg–Landau theory of superconductivity. Overview The solution is a combination of fluxon solution by Fritz London, combined with a concept of core of quantum vortex by Lars Onsager. In the quantum vortex, supercurrent circulates around the normal (i.e. non-superconducting) core of the vortex. The core has a size \sim\xi — the superconducting coherence length (parameter of a Ginzburg–Landau theory). The supercurrents decay on the distance about \lambda (London penetration depth) from the core. Note that in type-II superconductors \lambda>\xi/\sqrt. The circulating supercurrents induce magnetic fields with the total flux equal to a single flux quantum \Phi_0. Therefore, an Abrikosov vortex is often called ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Metallic Hydrogen
Metallic hydrogen is a phase (matter), phase of hydrogen in which it behaves like an electrical conductor. This phase was predicted in 1935 on theoretical grounds by Eugene Wigner and Hillard Bell Huntington. At high pressure and temperatures, metallic hydrogen can exist as a partial liquid rather than a solid, and researchers think it might be present in large quantities in the hot and gravitationally compressed interiors of Jupiter and Saturn, as well as in some exoplanets. Theoretical predictions Hydrogen under pressure Though often placed at the top of the alkali metal column in the periodic table, hydrogen does not, under ordinary conditions, exhibit the properties of an alkali metal. Instead, it forms Diatomic molecule, diatomic molecules, analogous to halogens and some nonmetals in the second period of the periodic table, such as nitrogen and oxygen. Diatomic hydrogen is a gas that, at atmospheric pressure, Liquid hydrogen, liquefies and Solid hydrogen, solidifies only at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
