q-Canonical transformations for many q-bosons and new q–k symmetry

1994 ◽  
Vol 72 (7-8) ◽  
pp. 321-325
Author(s):  
Joseph L. Birman
Keyword(s):  
Plane Wave ◽  
Wave Vector ◽  
Canonical Transformation ◽  
Bose System ◽  
Canonical Transformations ◽  
Negative Wave ◽  
The Many ◽  
Wave Modes

A new symmetry is identified for the many particle q-Bose system, which permits carrying out a linear q-canonical transformation, i.e., one which preserves the q-deformed commutation rules. The symmetry is exhibited when the set of q-modes is partitioned into "positive" and "negative," each subset having its own type of deformation. For plane-wave modes, labelled by wave vector k, this means separate positive and negative wave vectors. Then, identifying the new symmetry: (q → q−1, k → −k) the transformation can be implemented. The new aspect is the simultaneous transformation of wave vector k and parameter q.

Eine kanonische Transformation als Lösungsvorschlag für eine Funktionalgleichung

1980 ◽  
Vol 35 (6) ◽  
pp. 567-578
Author(s):  
F. Wahl
Keyword(s):  
Functional Equation ◽  
Canonical Transformation ◽  
Body Problem ◽  
Electronic States ◽  
Simple Approach ◽  
Canonical Transformations ◽  
Many Body ◽  
Hydrogen In Metals ◽  
The Many ◽  
Inequivalent Representations

A Canonical Transformation as a Proposal of the Solution of a Functional EquationStarting with a functional equation of the New Tamm-Dancoff procedure for electronic states of defects in solids we describe an attempt to transform this equation. The aim is to extract a one-particle equation as a projection which is a good approximation for the case of a defect. The transformation usetii s a simple approach to more general canonical transformations leading to inequivalent representations of the many-body problem. It is compared with the elimination procedure given in a first paper [1] which treated the manj-electron problem occuring with the storage of hydrogen in metals

scholarly journals Mechanisms of electron-phonon coupling unraveled in momentum and time: The case of soft phonons in TiSe2

2021 ◽  
Vol 7 (20) ◽  
pp. eabf2810
Author(s):  
Martin R. Otto ◽  
Jan-Hendrik Pöhls ◽  
Laurent P. René de Cotret ◽  
Mark J. Stern ◽  
Mark Sutton ◽  
...  
Keyword(s):  
Wave Vector ◽  
Density Wave ◽  
Phonon Coupling ◽  
Many Body ◽  
Soft Zone ◽  
Electron Phonon Coupling ◽  
Underlying Mechanisms ◽  
The Many ◽  
Coupling Phenomena ◽  
Electron Pocket

The complex coupling between charge carriers and phonons is responsible for diverse phenomena in condensed matter. We apply ultrafast electron diffuse scattering to unravel electron-phonon coupling phenomena in 1T-TiSe2 in both momentum and time. We are able to distinguish effects due to the real part of the many-body bare electronic susceptibility, R[χ0(q)], from those due to the electron-phonon coupling vertex, gq, by following the response of semimetallic (normal-phase) 1T-TiSe2 to the selective photo-doping of carriers into the electron pocket at the Fermi level. Quasi-impulsive and wave vector–specific renormalization of soft zone-boundary phonon frequencies (stiffening) is observed, followed by wave vector–independent electron-phonon equilibration. These results unravel the underlying mechanisms driving the phonon softening that is associated with the charge density wave transition at lower temperatures.

scholarly journals Theory of Generalized Canonical Transformations for Birkhoff Systems

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yi Zhang
Keyword(s):  
Canonical Transformation ◽  
Natural Generalization ◽  
Analytical Mechanics ◽  
Hamiltonian Mechanics ◽  
Canonical Transformations ◽  
Transformation Theory ◽  
Special Cases ◽  
Criterion Equation ◽  
Important Means ◽  
Transformation Formulas

Transformation is an important means to study problems in analytical mechanics. It is often difficult to solve dynamic equations, and the use of variable transformation can make the equations easier to solve. The theory of canonical transformations plays an important role in solving Hamilton’s canonical equations. Birkhoffian mechanics is a natural generalization of Hamiltonian mechanics. This paper attempts to extend the canonical transformation theory of Hamilton systems to Birkhoff systems and establish the generalized canonical transformation of Birkhoff systems. First, the definition and criterion of the generalized canonical transformation for the Birkhoff system are established. Secondly, based on the criterion equation and considering the generating functions of different forms, six generalized canonical transformation formulas are derived. As special cases, the canonical transformation formulas of classical Hamilton’s equations are given. At the end of the paper, two examples are given to illustrate the application of the results.

Anatomy of the canonical transformation

1993 ◽  
Vol 345 (1677) ◽  
pp. 577-598 ◽  
Keyword(s):  
Fluid Dynamics ◽  
Canonical Transformation ◽  
Generating Functions ◽  
Hamiltonian Structure ◽  
Rigid Bodies ◽  
Symplectic Integrators ◽  
Classical Dynamics ◽  
Canonical Transformations ◽  
Geophysical Fluid Dynamics ◽  
Dynamics Of Particles

A concise account of the structure of the canonical transformation is given, in the lowest dimensional case. This case is chosen because it offers a special clarity in several respects. In particular, the diversity of possible generating functions is illustrated by m any examples which are not available elsewhere. Many of these are of physical interest, and some of them are multivalued. These examples are used to inform a comparative study of the several different definitions of a canonical transformation to be found in the literature. The paper is pertinent to all those branches of mechanics which can be given a hamiltonian representation. These include not only the classical dynamics of particles and rigid bodies, but also some more recent studies in continuum mechanics, including geophysical fluid dynamics. An area of particular modern interest is that of symplectic integrators. These are numerical integrating algorithms which generate a solution to Hamilton’s equations via a sequence of canonical transformations, which preserve the hamiltonian structure in the numerical solution.

scholarly journals LOCAL EXPONENTS AND INFINITESIMAL GENERATORS OF CANONICAL TRANSFORMATIONS ON BOSON FOCK SPACES

2004 ◽  
Vol 07 (04) ◽  
pp. 547-571 ◽  
Author(s):  
F. HIROSHIMA ◽  
K. R. ITO
Keyword(s):  
Canonical Transformation ◽  
Symplectic Group ◽  
Unitary Operator ◽  
Fock Space ◽  
Adjoint Operator ◽  
The Self ◽  
Canonical Transformations ◽  
Fock Spaces ◽  
Infinitesimal Generators ◽  
Boson Fock Space

A one-parameter symplectic group {etÂ}t∈ℝ derives proper canonical transformations indexed by t on a Boson–Fock space. It has been known that the unitary operator Ut implementing such a proper canonical transformation gives a projective unitary representation of {etÂ}t∈ℝ on the Boson–Fock space and that Ut can be expressed as a normal-ordered form. We rigorously derive the self-adjoint operator Δ(Â) and a local exponent [Formula: see text] with a real-valued function τÂ(·) such that [Formula: see text].

scholarly journals CANONICAL TRANSFORMATIONS IN THREE-DIMENSIONAL PHASE-SPACE

2009 ◽  
Vol 24 (25n26) ◽  
pp. 4769-4788 ◽  
Author(s):  
TEKİN DERELİ ◽  
ADNAN TEĞMEN ◽  
TUĞRUL HAKİOĞLU
Keyword(s):  
Phase Space ◽  
Canonical Transformation ◽  
Generating Functions ◽  
General Framework ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Canonical Transformations ◽  
Dimensional Phase Space ◽  
Nambu Bracket ◽  
Definition Of

Canonical transformation in a three-dimensional phase-space endowed with Nambu bracket is discussed in a general framework. Definition of the canonical transformations is constructed based on canonoid transformations. It is shown that generating functions, transformed Hamilton functions and the transformation itself for given generating functions can be determined by solving Pfaffian differential equations corresponding to that quantities. Types of the generating functions are introduced and all of them are listed. Infinitesimal canonical transformations are also discussed. Finally, we show that the decomposition of canonical transformations is also possible in three-dimensional phase space as in the usual two-dimensional one.

Canonical transformations

2020 ◽  
pp. 317-337
Author(s):  
Gleb L. Kotkin ◽  
Valeriy G. Serbo
Keyword(s):  
Magnetic Field ◽  
Harmonic Oscillator ◽  
Canonical Transformation ◽  
Hamiltonian Function ◽  
Harmonic Oscillators ◽  
Nonlinear Coupling ◽  
Canonical Transformations ◽  
Canonical Variables ◽  
Anharmonic Oscillations ◽  
The Given

This chapter addresses the canonical transformation defined by the given generating function, the rotation in the phase space as a canonical transformation, and themovement of the system as a canonical transformation. The chapter also discusses using the canonical transformations for solving the problems of the anharmonic oscillations and using the canonical transformation to diagonalize the Hamiltonian function of an anisotropic charged harmonic oscillator in a magnetic field. Finally, the chapter addresses the canonical variables which reduce the Hamiltonian function of the harmonic oscillator to zero and using them for consideration of the system of the harmonic oscillators with the weak nonlinear coupling.

scholarly journals QUANTUM CANONICAL TRANSFORMATIONS IN WEYL–WIGNER–GROENEWOLD–MOYAL FORMALISM

2009 ◽  
Vol 24 (24) ◽  
pp. 4573-4587 ◽  
Author(s):  
TEKİN DERELİ ◽  
TUĞRUL HAKİOĞLU ◽  
ADNAN TEĞMEN
Keyword(s):  
Quantum Mechanics ◽  
Phase Space ◽  
Generating Function ◽  
Canonical Transformation ◽  
Star Product ◽  
Product Form ◽  
Canonical Transformations ◽  
Exponential Form ◽  
Alternative Approach ◽  
Point Transformations

A conjecture in quantum mechanics states that any quantum canonical transformation can decompose into a sequence of three basic canonical transformations; gauge, point and interchange of coordinates and momenta. It is shown that if one attempts to construct the three basic transformations in star-product form, while gauge and point transformations are immediate in star-exponential form, interchange has no correspondent, but it is possible in an ordinary exponential form. As an alternative approach, it is shown that all three basic transformations can be constructed in the ordinary exponential form and that in some cases this approach provides more useful tools than the star-exponential form in finding the generating function for given canonical transformation or vice versa. It is also shown that transforms of c-number phase space functions under linear–nonlinear canonical transformations and intertwining method can be treated within this argument.

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