ORBITAL ANGULAR MOMENTUM OF GAUGE FIELDS: EXCITATION OF AN ATOM BY TWISTED PHOTONS

Twisted photon states, or photon states with large (> ℏ) angular momentum projection in the direction of motion, can photoexcite atomic final states of differing quantum numbers. If the photon symmetry axis coincides with the center of an atom, there are known selection rules that require exact matching between the quantum numbers of the photon and the photoexcited states. The more general case of arbitrarily positioned beams relaxes the selection rules but produces a distribution of quantum numbers of the final atomic states that is novel and distinct from final states produced by plane-wave photons. Numerical calculations are presented using a hydrogen atom as an example.

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INDUCED QUANTUM NUMBERS IN SOME 2 + 1 DIMENSIONAL MODELS

International Journal of Modern Physics A ◽

10.1142/s0217751x8900025x ◽

1989 ◽

Vol 04 (02) ◽

pp. 493-493

Author(s):

YI-HONG CHEN ◽

FRANK WILCZEK

Keyword(s):

Angular Momentum ◽

Gauge Fields ◽

Quantum Numbers ◽

Local Current ◽

Current Densities ◽

Dimensional Models ◽

Background Fields ◽

Fermion Current ◽

Spin And Statistics

The fermion current induced by slow variations in background scalar and gauge fields are computed for a class of 2 + 1 dimensional σ-like models. Local current densities proportional to topological currents in the background fields are found. The coefficient depends discontinuously on certain field ratios. The induced fermion numbers we find, mesh nicely with recent results on induced angular momentum and induced statistics. In particular, the spin and statistics is intimately related to the global parity anomaly. Lattice realizations are suggested.

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Hadronic currents and form factors in three-body semileptonic $$\tau $$ decays

The European Physical Journal C ◽

10.1140/epjc/s10052-021-09876-1 ◽

2021 ◽

Vol 81 (12) ◽

Author(s):

Fabian Krinner ◽

Stephan Paul

Keyword(s):

Angular Momentum ◽

Orbital Angular Momentum ◽

Dipole Moments ◽

Form Factors ◽

Decay Chain ◽

Full Description ◽

Final States ◽

Arbitrary Mass ◽

Quantum Numbers ◽

Three Body

AbstractThree-body semileptonic $$\tau $$ τ -decays offer a path to understand the properties of light hadronic systems and CP symmetry violations through searches for electric dipole moments. In studies of electro-weak physics, the hadronic part of the final states has traditionally been described using the language of form factors. Spectroscopic information, resolved in terms of orbital angular momentum quantum-numbers, is best being derived from an explicit decomposition of the hadronic current in the orbital angular momentum basis. Motivated by the upcoming large data samples from $$\mathrm {B}$$ B factories, we present the full description of the hadronic currents decomposed into quantum numbers of the hadronic final state using the isobar picture. We present formulas for orbital angular momenta up to three and apply the rules derived from hadron spectroscopy to formulate the decay chain of hadronic three-body systems of arbitrary mass. We also translate this formalism to the language of form factors and thereby correct insufficiencies found in previous analyses of three-body hadronic final states.

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INDUCED QUANTUM NUMBERS IN SOME 2 + 1 DIMENSIONAL MODELS

International Journal of Modern Physics B ◽

10.1142/s0217979289000117 ◽

1989 ◽

Vol 03 (01) ◽

pp. 117-128 ◽

Cited By ~ 14

Author(s):

YI-HONG CHEN ◽

FRANK WILCZEK

Keyword(s):

Angular Momentum ◽

Gauge Fields ◽

Quantum Numbers ◽

Local Current ◽

Current Densities ◽

Dimensional Models ◽

Background Fields ◽

Fermion Current ◽

Spin And Statistics

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Multiplicity, Parity and Angular Momentum of a Cooper Pair in Unconventional Superconductors of D4h Symmetry: Sr2RuO4 and Fe-Pnictide Materials

Symmetry ◽

10.3390/sym13081435 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1435

Author(s):

Victor G. Yarzhemsky

Keyword(s):

Angular Momentum ◽

Cooper Pair ◽

Point Group ◽

Group Symmetry ◽

Cooper Pairs ◽

Group Approach ◽

Angular Momentum Projection ◽

Space Group ◽

Unconventional Superconductors ◽

Even Pairs

Sr2RuO4 and Fe-pnictide superconductors belong to the same point group symmetry D4h. Many experimental data confirm odd pairs in Sr2RuO4 and even pairs in Fe-pnictides, but opposite conclusions also exist. Recent NMR results of Pustogow et al., which revealed even Cooper pairs in Sr2RuO4, require reconsideration of symmetry treatment of its SOP (superconducting order parameter). In the present work making use of the Mackey–Bradley theorem on symmetrized squares, a group theoretical investigation of possible pairing states in D4h symmetry is performed. It is obtained for I4/mmm , i.e., space group of Sr2RuO4, that triplet pairs with even spatial parts are possible in kz direction and in points M and Y. For the two latter cases pairing of equivalent electrons with nonzero total momentum is proposed. In P4/nmm space group of Fe- pnictides in point M, even and odd pairs are possible for singlet and triplet cases. It it shown that even and odd chiral states with angular momentum projection m=±1 have nodes in vertical planes, but Eg is nodal , whereas Eu is nodeless in the basal plane. It is also shown that the widely accepted assertion that the parity of angular momentum value is directly connected with the spatial parity of a pair is not valid in a space-group approach to the wavefunction of a Cooper pair.

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