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List Of Things Named After Julian Schwinger
{{Short description, none Things named after physicist Julian Schwinger include the following: *Schwinger effect (Schwinger pair production) *Schwinger function *Schwinger limit * Schwinger model *Schwinger parametrization * Schwinger representation * Schwinger reversed-phase coupler * Schwinger variational principle * Schwinger's quantum action principle *Schwinger–Dyson equation * Schwinger–Tomonaga equation * Fock–Schwinger gauge * Jordan-Schwinger map * Rarita–Schwinger equation *Lippmann–Schwinger equation The Lippmann–Schwinger equation (named after Bernard Lippmann and Julian Schwinger) is one of the most used equations to describe particle collisions – or, more precisely, scattering – in quantum mechanics. It may be used in scatt ... * Kubo–Martin–Schwinger state schwinger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Julian Schwinger
Julian Seymour Schwinger (; February 12, 1918 – July 16, 1994) was a Nobel Prize winning American theoretical physicist. He is best known for his work on quantum electrodynamics (QED), in particular for developing a relativistically invariant perturbation theory, and for renormalizing QED to one loop order. Schwinger was a physics professor at several universities. Schwinger is recognized as one of the greatest physicists of the twentieth century, responsible for much of modern quantum field theory, including a variational approach, and the equations of motion for quantum fields. He developed the first electroweak model, and the first example of confinement in 1+1 dimensions. He is responsible for the theory of multiple neutrinos, Schwinger terms, and the theory of the spin-3/2 field. Biography Early life and career Julian Seymour Schwinger was born in New York City, to Ashkenazi Jewish parents, Belle (née Rosenfeld) and Benjamin Schwinger, a garment manufacturer, who had e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schwinger's Quantum Action Principle
The Schwinger's quantum action principle is a variational approach to quantum mechanics and quantum field theory. This theory was introduced by Julian Schwinger in a series of articles starting 1950. Approach In Schwingers approach, the action principle is targeted towards quantum mechanics. The action becomes a quantum action, i.e. an operator, S . Although it is superficially different from the path integral formulation where the action is a classical function, the modern formulation of the two formalisms are identical. Suppose we have two states defined by the values of a complete set of commuting operators at two times. Let the early and late states be , A \rang and , B \rang, respectively. Suppose that there is a parameter in the Lagrangian which can be varied, usually a source for a field. The main equation of Schwinger's quantum action principle is: : \delta \langle B, A\rangle = i \langle B, \delta S , A\rangle,\ where the derivative is with respect to small ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lippmann–Schwinger Equation
The Lippmann–Schwinger equation (named after Bernard Lippmann and Julian Schwinger) is one of the most used equations to describe particle collisions – or, more precisely, scattering – in quantum mechanics. It may be used in scattering of molecules, atoms, neutrons, photons or any other particles and is important mainly in atomic, molecular, and optical physics, nuclear physics and particle physics, but also for seismic scattering problems in geophysics. It relates the scattered wave function with the interaction that produces the scattering (the scattering potential) and therefore allows calculation of the relevant experimental parameters (scattering amplitude and cross sections). The most fundamental equation to describe any quantum phenomenon, including scattering, is the Schrödinger equation. In physical problems, this differential equation must be solved with the input of an additional set of initial and/or boundary conditions for the specific physical system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rarita–Schwinger Equation
In theoretical physics, the Rarita–Schwinger equation is the relativistic field equation of spin-3/2 fermions. It is similar to the Dirac equation for spin-1/2 fermions. This equation was first introduced by William Rarita and Julian Schwinger in 1941. In modern notation it can be written as: : \left ( \epsilon^ \gamma_5 \gamma_\kappa \partial_\rho - i m \sigma^ \right)\psi_\nu = 0 where \epsilon^ is the Levi-Civita symbol, \gamma_5 and \gamma_\nu are Dirac matrices, m is the mass, \sigma^ \equiv \frac gamma^\mu,\gamma^\nu, and \psi_\nu is a vector-valued spinor with additional components compared to the four component spinor in the Dirac equation. It corresponds to the representation of the Lorentz group, or rather, its part. This field equation can be derived as the Euler–Lagrange equation corresponding to the Rarita–Schwinger Lagrangian: :\mathcal=-\tfrac\;\bar_\mu \left ( \epsilon^ \gamma_5 \gamma_\kappa \partial_\rho - i m \sigma^ \right)\psi_\nu where th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jordan-Schwinger Map
In theoretical physics, the Jordan map, often also called the Jordan–Schwinger map is a map from matrices to bilinear expressions of quantum oscillators which expedites computation of representations of Lie algebras occurring in physics. It was introduced by Pascual Jordan in 1935 and was utilized by Julian Schwinger in 1952 to re-work out the theory of quantum angular momentum efficiently, given that map’s ease of organizing the (symmetric) representations of su(2) in Fock space. The map utilizes several creation and annihilation operators a^\dagger_i and a^_i of routine use in quantum field theories and many-body problems, each pair representing a quantum harmonic oscillator. The commutation relations of creation and annihilation operators in a multiple-boson system are, : ^_i, a^\dagger_j\equiv a^_i a^\dagger_j - a^\dagger_ja^_i = \delta_, : ^\dagger_i, a^\dagger_j= ^_i, a^_j= 0, where \ , \ \ /math> is the commutator and \delta_ is the Kronecker delta. These o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fock–Schwinger Gauge
In the physics of gauge theory, gauge theories, gauge fixing (also called choosing a gauge) denotes a mathematical procedure for coping with redundant Degrees of freedom (physics and chemistry), degrees of freedom in field (physics), field variables. By definition, a gauge theory represents each physically distinct configuration of the system as an equivalence class of detailed local field configurations. Any two detailed configurations in the same equivalence class are related by a gauge transformation, equivalent to a symmetry transformation, shear along unphysical axes in configuration space. Most of the quantitative physical predictions of a gauge theory can only be obtained under a coherent prescription for suppressing or ignoring these unphysical degrees of freedom. Although the unphysical axes in the space of detailed configurations are a fundamental property of the physical model, there is no special set of directions "perpendicular" to them. Hence there is an enormous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
