Klassische Größen und quantenmechanische Operatoren in allgemeinen Koordinaten

1968 ◽  
Vol 23 (2) ◽  
pp. 199-203 ◽  
Author(s):  
H. Näpfel ◽  
H. Ruder ◽  
H. Volz
Keyword(s):  
Quantum Case ◽  
Angular Momenta ◽  
Translation Rule ◽  
Infinitesimal Transformations

A method is given to find, in general coordinates, expressions for dynamical quantities connected with infinitesimal transformations. The classical and the corresponding quantum case are considered. A simple translation rule between the two cases is derived by comparison. The efficiency of the method is demonstrated in the example of angular momenta.

scholarly journals The first-order symmetry operator on gravitational perturbations in the 5D Myers–Perry spacetime with equal angular momenta

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Masataka Tsuchiya ◽  
Tsuyoshi Houri ◽  
Chul Moon Yoo
Keyword(s):  
Field Equation ◽  
Linear Combination ◽  
Symmetry Operator ◽  
First Order ◽  
Gravitational Perturbations ◽  
Angular Momenta ◽  
Mode Decomposition ◽  
Vacuum Spacetime ◽  
Infinitesimal Transformations ◽  
Metric Perturbation

Abstract It has been revealed that the first-order symmetry operator for the linearized Einstein equation on a vacuum spacetime can be constructed from a Killing–Yano 3-form. This might be used to construct all or part of the solutions to the field equation. In this paper, we perform a mode decomposition of a metric perturbation on the Schwarzschild spacetime and the Myers–Perry spacetime with equal angular momenta in 5 dimensions, and investigate the action of the symmetry operator on specific modes concretely. We show that, on such spacetimes, there is no transition between the modes of a metric perturbation by the action of the symmetry operator, and it ends up being the linear combination of the infinitesimal transformations of isometry.

Eine Lösungstheorie für das quantenmechanische Vier-Körper-Problem

1969 ◽  
Vol 24 (8) ◽  
pp. 1163-1171 ◽  
Author(s):  
W Büttner ◽  
H Ruder
Keyword(s):  
Angular Momentum ◽  
Kinetic Energy ◽  
Body Problem ◽  
Rotational Symmetry ◽  
Center Of Mass ◽  
Classical Case ◽  
Angular Momenta ◽  
Internal Coordinates ◽  
Symmetry Properties ◽  
Translation Rule

AbstractA system of 4 point masses (without spin) is considered. The potential energy is assumed to be a function of the distances between the particles only. It is possible to express the kinetic energy relative to the center of mass as the kinetic energy of 3 "reduced" masses. The different possibilities for that procedure are discussed for systems with an arbitrary number of particles. The positions of the 3 reduced masses are described by 9 coordinates. 6 of them, the "internal" coordinates, are needed to determine the internal structure of the system, and 3, the "external" coordinates, for its orientation in space. The classical Hamiltonian in such a set of coordinates is derived. In a first step the Hamiltonian is expressed in terms of linear and angular momenta. Then these quantities are determined as functions of the coordinates and the conjugate momenta by infinitesimal trans-formations. From the classical Hamiltonian we get the quantum mechanical one by the well-known translation rule. It can be expressed in terms of the linear and angular momentum operators quite analogous to the classical case. For the solution of the time-independent Schrödinger equation the rotational symmetry of the system is used. The wave function is expanded in terms of the eigenfunctions of the total angular momentum. This leads to a system of coupled differential equations for the expansion-coefficients which depend on the 6 internal coordinates only. The further symmetries of the system (reflection and particle exchange) appear in symmetry properties of these functions. Differences and similarities in the solution theory for the 4-body-problem with respect to the 3-body-problem are discussed.

Photonic quantum Hall effect and multiplexed light sources of large orbital angular momenta

2021 ◽  
Author(s):  
Babak Bahari ◽  
Liyi Hsu ◽  
Si Hui Pan ◽  
Daryl Preece ◽  
Abdoulaye Ndao ◽  
...  
Keyword(s):  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Light Sources ◽  
Angular Momenta

scholarly journals Spin-decoupled metasurface for simultaneous detection of spin and orbital angular momenta via momentum transformation

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Yinghui Guo ◽  
Shicong Zhang ◽  
Mingbo Pu ◽  
Qiong He ◽  
Jinjin Jin ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Simultaneous Detection ◽  
Single Element ◽  
Single Shot ◽  
Single Spin ◽  
Dual Functional ◽  
Angular Momenta ◽  
Quadratic Phase ◽  
Mode Space ◽  
Optical Configuration

AbstractWith inherent orthogonality, both the spin angular momentum (SAM) and orbital angular momentum (OAM) of photons have been utilized to expand the dimensions of quantum information, optical communications, and information processing, wherein simultaneous detection of SAMs and OAMs with a single element and a single-shot measurement is highly anticipated. Here, a single azimuthal-quadratic phase metasurface-based photonic momentum transformation (PMT) is illustrated and utilized for vortex recognition. Since different vortices are converted into focusing patterns with distinct azimuthal coordinates on a transverse plane through PMT, OAMs within a large mode space can be determined through a single-shot measurement. Moreover, spin-controlled dual-functional PMTs are proposed for simultaneous SAM and OAM sorting, which is implemented by a single spin-decoupled metasurface that merges both the geometric phase and dynamic phase. Interestingly, our proposed method can detect vectorial vortices with both phase and polarization singularities, as well as superimposed vortices with a certain interval step. Experimental results obtained at several wavelengths in the visible band exhibit good agreement with the numerical modeling. With the merits of ultracompact device size, simple optical configuration, and prominent vortex recognition ability, our approach may underpin the development of integrated and high-dimensional optical and quantum systems.

scholarly journals Circular polariton currents with integer and fractional orbital angular momenta

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
E. S. Sedov ◽  
V. A. Lukoshkin ◽  
V. K. Kalevich ◽  
P. G. Savvidis ◽  
A. V. Kavokin
Keyword(s):  
Angular Momenta

scholarly journals Integrated structured light architectures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Randy Lemons ◽  
Wei Liu ◽  
Josef C. Frisch ◽  
Alan Fry ◽  
Joseph Robinson ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Temporal Distribution ◽  
Multiple Degrees Of Freedom ◽  
Beam Combination ◽  
Angular Momenta ◽  
Field Control ◽  
Topological States ◽  
Spatio Temporal ◽  
Temporal Field ◽  
Structural Versatility

AbstractThe structural versatility of light underpins an outstanding collection of optical phenomena where both geometrical and topological states of light can dictate how matter will respond or display. Light possesses multiple degrees of freedom such as amplitude, and linear, spin angular, and orbital angular momenta, but the ability to adaptively engineer the spatio-temporal distribution of all these characteristics is primarily curtailed by technologies used to impose any desired structure to light. We demonstrate a laser architecture based on coherent beam combination offering integrated spatio-temporal field control and programmability, thereby presenting unique opportunities for generating light by design to exploit its topology.

scholarly journals Elaborated subloading surface model for accurate description of cyclic mobility in granular materials

2021 ◽  
Author(s):  
Koichi Hashiguchi ◽  
Tatsuya Mase ◽  
Yuki Yamakawa
Keyword(s):  
Cyclic Loading ◽  
Granular Materials ◽  
Accurate Description ◽  
Surface Model ◽  
Cyclic Mobility ◽  
Mixed Hardening ◽  
Hardening Rule ◽  
Elastic Domain ◽  
Translation Rule ◽  
Rotational Hardening

AbstractThe description of the cyclic mobility observed prior to the liquefaction in geomaterials requires the sophisticated constitutive formulation to describe the plastic deformation induced during the cyclic loading with the small stress amplitude inside the yield surface. This requirement is realized in the subloading surface model, in which the surface enclosing a purely elastic domain is not assumed, while a purely elastic domain is assumed in other elastoplasticity models. The subloading surface model has been applied widely to the monotonic/cyclic loading behaviors of metals, soils, rocks, concrete, etc., and the sufficient predictions have been attained to some extent. The subloading surface model will be elaborated so as to predict also the cyclic mobility accurately in this article. First, the rigorous translation rule of the similarity center of the normal yield and the subloading surfaces, i.e., elastic core, is formulated. Further, the mixed hardening rule in terms of volumetric and deviatoric plastic strain rates and the rotational hardening rule are formulated to describe the induced anisotropy of granular materials. In addition, the material functions for the elastic modulus, the yield function and the isotropic hardening/softening will be modified for the accurate description of the cyclic mobility. Then, the validity of the present formulation will be verified through comparisons with various test data of cyclic mobility.

scholarly journals Mixing indistinguishable systems leads to a quantum Gibbs paradox

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Benjamin Yadin ◽  
Benjamin Morris ◽  
Gerardo Adesso
Keyword(s):  
Statistical Mechanics ◽  
Thought Experiment ◽  
Entropy Change ◽  
Ideal Gas ◽  
Gibbs Paradox ◽  
Quantum Case ◽  
Entropy Increase ◽  
Level Of Knowledge ◽  
Different Gases ◽  
As If

AbstractThe classical Gibbs paradox concerns the entropy change upon mixing two gases. Whether an observer assigns an entropy increase to the process depends on their ability to distinguish the gases. A resolution is that an “ignorant” observer, who cannot distinguish the gases, has no way of extracting work by mixing them. Moving the thought experiment into the quantum realm, we reveal new and surprising behaviour: the ignorant observer can extract work from mixing different gases, even if the gases cannot be directly distinguished. Moreover, in the macroscopic limit, the quantum case diverges from the classical ideal gas: as much work can be extracted as if the gases were fully distinguishable. We show that the ignorant observer assigns more microstates to the system than found by naive counting in semiclassical statistical mechanics. This demonstrates the importance of accounting for the level of knowledge of an observer, and its implications for genuinely quantum modifications to thermodynamics.

scholarly journals Hamiltonian charges in the asymptotically de Sitter spacetimes

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Maciej Kolanowski ◽  
Jerzy Lewandowski
Keyword(s):  
Phase Space ◽  
Initial Data ◽  
Exact Solutions ◽  
Gravitational Waves ◽  
Physical Meaning ◽  
De Sitter ◽  
Killing Vectors ◽  
Asymptotically Flat ◽  
Angular Momenta ◽  
The One

Abstract We generalize a notion of ‘conserved’ charges given by Wald and Zoupas to the asymptotically de Sitter spacetimes. Surprisingly, our construction is less ambiguous than the one encountered in the asymptotically flat context. An expansion around exact solutions possessing Killing vectors provides their physical meaning. In particular, we discuss a question of how to define energy and angular momenta of gravitational waves propagating on Kottler and Carter backgrounds. We show that obtained expressions have a correct limit as Λ → 0. We also comment on the relation between this approach and the one based on the canonical phase space of initial data at ℐ+.

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