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Slave Boson
The slave boson method is a technique for dealing with models of strongly correlated systems, providing a method to second-quantize valence fluctuations within a restrictive manifold of states. In the 1960s the physicist John Hubbard introduced an operator, now named the "Hubbard operator" to describe the creation of an electron within a restrictive manifold of valence configurations. Consider for example, a rare earth or actinide ion in which strong Coulomb interactions restrict the charge fluctuations to two valence states, such as the Ce4+(4f0) and Ce3+ (4f1) configurations of a mixed-valence cerium compound. The corresponding quantum states of these two states are the singlet \vert f^0\rangle state and the magnetic \vert f^1:\sigma\rangle state, where \sigma=\uparrow,\ \downarrow is the spin. The fermionic Hubbard operators that link these states are then The algebra of operators is closed by introducing the two bosonic operators Together, these operators satisfy the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strongly Correlated Material
Strongly correlated materials are a wide class of compounds that include insulators and electronic materials, and show unusual (often technologically useful) electronic and magnetic properties, such as metal-insulator transitions, heavy fermion behavior, half-metallicity, and spin-charge separation. The essential feature that defines these materials is that the behavior of their electrons or spinons cannot be described effectively in terms of non-interacting entities. Theoretical models of the electronic ( fermionic) structure of strongly correlated materials must include electronic ( fermionic) correlation to be accurate. As of recently, the label quantum materials is also used to refer to strongly correlated materials, among others. Transition metal oxides Many transition metal oxides belong to this class which may be subdivided according to their behavior, ''e.g.'' high-Tc, spintronic materials, multiferroics, Mott insulators, spin Peierls materials, heavy ferm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Hubbard (physicist)
John Hubbard ( – ) was a British physicist working in the areas of solid-state and condensed matter physics. He is best known for the Hubbard model for interacting electrons and the Hubbard-Stratonovich transformation, both of which have found many applications beyond his original work. Early life and education John Hubbard was born on to Charles and Marion Hubbard. He spent most of his childhood in Teddington, London, and lived with his parents through his university education. Hubbard attended Hampton Grammar School and then entered Imperial College London. He received his Bachelor of Science in 1955, and his PhD in 1958 under the supervision of Stanley Raimes in the Department of Mathematics. For his thesis he worked on the “dielectric approach” to treating the Coulomb interaction between electrons in metals. Immediately thereafter he was hired to work at the Atomic Energy Research Establishment, Harwell by Brian Flowers, who was at the time head of the Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerium
Cerium is a chemical element; it has Chemical symbol, symbol Ce and atomic number 58. It is a hardness, soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it often shows the oxidation state of +3 characteristic of the series, it also has a stable +4 state that does not oxidize water. It is considered one of the rare-earth elements. Cerium has no known biological role in humans but is not particularly toxic, except with intense or continued exposure. Despite always occurring in combination with the other rare-earth elements in minerals such as those of the monazite and bastnäsite groups, cerium is easy to extract from its ores, as it can be distinguished among the lanthanides by its unique ability to be oxidized to the +4 state in aqueous solution. It is the most common of the lanthanides, followed by neodymium, lanthanum, and praseodymium. Its estimated abundance of elements in Earth's crust, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
