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Byers–Yang Theorem
In quantum mechanics, the Byers–Yang theorem states that all physical properties of a doubly connected system (an annulus) enclosing a magnetic flux \Phi through the opening are periodic in the flux with period \Phi_0=hc/e (the magnetic flux quantum). The theorem was first stated and proven by Nina Byers and Chen-Ning Yang (1961), and further developed by Felix Bloch (1970). Proof An enclosed flux \Phi corresponds to a vector potential A(r) inside the annulus with a line integral \oint_C A\cdot dl=\Phi along any path C that circulates around once. One can try to eliminate this vector potential by the gauge transformation : \psi'(\)=\exp\left(\frac\sum_j\chi(r_j)\right)\psi(\) of the wave function \psi(\) of electrons at positions r_1,r_2,\ldots. The gauge-transformed wave function satisfies the same Schrödinger equation as the original wave function, but with a different magnetic vector potential A'(r)=A(r)+\nabla\chi(r). It is assumed that the electrons experience zero magne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Mechanics
Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, quantum field theory, quantum technology, and quantum information science. Classical physics, the collection of theories that existed before the advent of quantum mechanics, describes many aspects of nature at an ordinary (macroscopic) scale, but is not sufficient for describing them at small (atomic and subatomic) scales. Most theories in classical physics can be derived from quantum mechanics as an approximation valid at large (macroscopic) scale. Quantum mechanics differs from classical physics in that energy, momentum, angular momentum, and other quantities of a bound system are restricted to discrete values ( quantization); objects have characteristics of both particles and waves (wave–particle duality); and there are limits to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Flux Quantum
The magnetic flux, represented by the symbol , threading some contour or loop is defined as the magnetic field multiplied by the loop area , i.e. . Both and can be arbitrary, meaning can be as well. However, if one deals with the superconducting loop or a hole in a bulk superconductor, the magnetic flux threading such a hole/loop is actually quantized. The (superconducting) magnetic flux quantum ≈ is a combination of fundamental physical constants: the Planck constant and the electron charge . Its value is, therefore, the same for any superconductor. The phenomenon of flux quantization was discovered experimentally by B. S. Deaver and W. M. Fairbank and, independently, by R. Doll and M. Näbauer, in 1961. The quantization of magnetic flux is closely related to the Little–Parks effect, but was predicted earlier by Fritz London in 1948 using a phenomenological model. The inverse of the flux quantum, , is called the Josephson constant, and is denoted J. It is the constan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nina Byers
Nina Byers (January 19, 1930 – June 5, 2014) was a theoretical physicist, Research Professor and Professor of Physics emeritus in the Department of Physics and Astronomy, UCLA, and Fellow of Somerville College, Oxford. Contributions Byers received a B.A. from the University of California, Berkeley in 1950 and a Ph.D. from the University of Chicago in 1956. Byers made phenomenological analyses of experimental observations leading to theoretical advances in particle physics and the theory of superconductivity. In "Theoretical considerations concerning quantized magnetic flux in superconductors," she showed that observation of flux quantization in superconductors in units of hc/2e is experimental evidence for the Cooper pairing of electrons proposed by the BCS theory of superconductivity ( Byers-Yang theorem). In addition to scientific papers, Byers published papers and edited a book on original and important contributions to modern physics by 20th century female physicists. She d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chen-Ning Yang
Yang Chen-Ning or Chen-Ning Yang (; born 1 October 1922), also known as C. N. Yang or by the English name Frank Yang, is a Chinese Theoretical physics, theoretical physicist who made significant contributions to statistical mechanics, integrable systems, gauge theory, and both particle physics and condensed matter physics. He and Tsung-Dao Lee received the 1957 Nobel Prize in Physics for their work on parity non-conservation of weak interaction. The two proposed that one of the basic quantum-mechanics laws, the conservation of parity, is violated in the so-called Weak interaction, weak nuclear reactions, those nuclear processes that result in the emission of beta particle, beta or alpha particles. Yang is also well known for his collaboration with Robert Mills (physicist), Robert Mills in developing non-abelian gauge theory, widely known as the Yang–Mills theory. Biography Yang was born in Hefei, Anhui, China; his father, (; 1896–1973), was a mathematician, and his mothe ... [...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] |
Felix Bloch
Felix Bloch (23 October 1905 – 10 September 1983) was a Swiss-American physicist and Nobel physics laureate who worked mainly in the U.S. He and Edward Mills Purcell were awarded the 1952 Nobel Prize for Physics for "their development of new ways and methods for nuclear magnetic precision measurements."Sohlman, M (Ed.) ''Nobel Foundation directory 2003.'' Vastervik, Sweden: AB CO Ekblad; 2003. In 1954–1955, he served for one year as the first Director-General of CERN. Felix Bloch made fundamental theoretical contributions to the understanding of ferromagnetism and electron behavior in crystal lattices. He is also considered one of the developers of nuclear magnetic resonance. Biography Early life, education, and family Bloch was born in Zürich, Switzerland to Jewish parents Gustav and Agnes Bloch. Gustav Bloch, his father, was financially unable to attend University and worked as a wholesale grain dealer in Zürich. Gustav moved to Zürich in 1890 to become a Swiss c ... [...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] |
Gauge Transformation
In physics, a gauge theory is a type of field theory in which the Lagrangian (and hence the dynamics of the system itself) does not change (is invariant) under local transformations according to certain smooth families of operations (Lie groups). The term ''gauge'' refers to any specific mathematical formalism to regulate redundant degrees of freedom in the Lagrangian of a physical system. The transformations between possible gauges, called ''gauge transformations'', form a Lie group—referred to as the ''symmetry group'' or the ''gauge group'' of the theory. Associated with any Lie group is the Lie algebra of group generators. For each group generator there necessarily arises a corresponding field (usually a vector field) called the ''gauge field''. Gauge fields are included in the Lagrangian to ensure its invariance under the local group transformations (called ''gauge invariance''). When such a theory is quantized, the quanta of the gauge fields are called ''gauge bosons' ... [...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 tran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schrödinger Equation
The Schrödinger equation is a linear partial differential equation that governs the wave function of a quantum-mechanical system. It is a key result in quantum mechanics, and its discovery was a significant landmark in the development of the subject. The equation is named after Erwin Schrödinger, who postulated the equation in 1925, and published it in 1926, forming the basis for the work that resulted in his Nobel Prize in Physics in 1933. Conceptually, the Schrödinger equation is the quantum counterpart of Newton's second law in classical mechanics. Given a set of known initial conditions, Newton's second law makes a mathematical prediction as to what path a given physical system will take over time. The Schrödinger equation gives the evolution over time of a wave function, the quantum-mechanical characterization of an isolated physical system. The equation can be derived from the fact that the time-evolution operator must be unitary, and must therefore be generated by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Vector Potential
In classical electromagnetism, magnetic vector potential (often called A) is the vector quantity defined so that its curl is equal to the magnetic field: \nabla \times \mathbf = \mathbf. Together with the electric potential ''φ'', the magnetic vector potential can be used to specify the electric field E as well. Therefore, many equations of electromagnetism can be written either in terms of the fields E and B, or equivalently in terms of the potentials ''φ'' and A. In more advanced theories such as quantum mechanics, most equations use potentials rather than fields. Magnetic vector potential was first introduced by Franz Ernst Neumann and Wilhelm Eduard Weber in 1845 and in 1846, respectively. Lord Kelvin also introduced vector potential in 1847, along with the formula relating it to the magnetic field. Magnetic vector potential The magnetic vector potential A is a vector field, defined along with the electric potential ''ϕ'' (a scalar field) by the equations: \mathbf = \n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yoseph Imry
Yoseph Imry (Hebrew: יוסף אמרי; born 23 February 1939 – 29 May 2018) was an Israeli physicist. He was best known for taking part in the foundation of mesoscopic physics, a relatively new branch of condensed matter physics. It is concerned with how the behavior of systems whose size is in between micro- and macroscopic, crosses over between these two regimes. These systems can be handled and addressed by more or less usual macroscopic methods, but their behavior may still show quantum effects. Awards and honours In 1996, 2001 and 2016, Imry received the Rothschild Prize, Israel Prize and Wolf Prize in physics, respectively. Imry was the 1996 Lorentz Professor at Leiden University. He was a member of the European Academy of Sciences and Arts (Salzburg), the European Academy of Sciences, Sciences and Humanities (Paris), the National Academy of Sciences, the American Physical Society and the Israel Academy of Sciences and Humanities. See also *List of Israel Prize reci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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