Magnetic moments and machinery of symmetry breaking

1979 ◽  
Vol 25 (4) ◽  
pp. 113-116 ◽  
Author(s):  
S. Iwao
Keyword(s):  
Symmetry Breaking ◽  
Magnetic Moments

scholarly journals BARYONS AS THREE-FLAVOR SOLITONS

1996 ◽  
Vol 11 (14) ◽  
pp. 2419-2544 ◽  
Author(s):  
HERBERT WEIGEL
Keyword(s):  
Symmetry Breaking ◽  
Vector Meson ◽  
Degrees Of Freedom ◽  
Magnetic Moments ◽  
Axial Vector ◽  
Vector Current ◽  
Bound State ◽  
Axial Vector Current ◽  
Flavor Symmetry ◽  
Matrix Elements

The description of baryons as soliton solutions of effective meson theories for three-flavor (up, down and strange) degrees of freedom is reviewed and the phenomenological implications are illuminated. In the collective approach the soliton configuration is equipped with baryon quantum numbers by canonical quantization of the coordinates describing the flavor orientation. The baryon spectrum resulting from exact diagonalization of the collective Hamiltonian is discussed. The prediction of static properties, such as the baryon magnetic moments and the Cabibbo matrix elements for semileptonic hyperon decays, are explored with regard to the influence of flavor symmetry breaking. In particular, the role of strange degrees of freedom in the nucleon is investigated for both the vector and axial vector current matrix elements. The latter are discussed extensively within the context of the proton spin puzzle. The influence of flavor symmetry breaking on the shape of the soliton is examined, and observed to cause significant deviations from flavor-covariant predictions on the baryon magnetic moments. Short range effects are incorporated by a chirally invariant inclusion of vector meson fields. These extensions are necessary for properly describing the singlet axial vector current and the neutron–proton mass difference. The effects of the vector meson excitations on baryon properties are also considered. The bound state description of hyperons and its generalization to baryons containing a heavy quark are illustrated. In the case of the Skyrme model a comparison is made between the collective quantization scheme and the bound state approach. Finally, the Nambu–Jona-Lasinio model is employed to demonstrate that hyperons can be described as solitons in a microscopic theory of the quark flavor dynamics. This is explained for both the collective and the bound state approaches to strangeness.

Magnetic moments of JP = 1/2+ baryons in broken SU(8)

1981 ◽  
Vol 59 (4) ◽  
pp. 506-510 ◽  
Author(s):  
Ramesh C. Verma
Keyword(s):  
Symmetry Breaking ◽  
Recent Experiment ◽  
Magnetic Moments ◽  
Transition Moment ◽  
Isospin Breaking ◽  
Charmed Baryon

Symmetry breaking effects on the magnetic moments of baryons are studied in the SU(8) framework. We obtain a low value of μ(Σ+) in agreement with a recent experiment. The transition moment [Formula: see text] seems to require isospin breaking, which also improves the overall fit to magnetic moments. Charmed baryon magnetic moments are calculated with and without isospin breaking.

scholarly journals Anisotropic Ferroelectric Distortion Effects on the RKKY Interaction in Topological Crystalline Insulators

2020 ◽  
Author(s):  
Hosein Cheraghchi ◽  
Mohsen Yarmohammadi
Keyword(s):  
Magnetic Properties ◽  
Symmetry Breaking ◽  
Mirror Symmetry ◽  
Magnetic Moments ◽  
Rkky Interaction ◽  
Dirac Materials ◽  
Nontrivial Behavior ◽  
Magnetic Orders ◽  
Mass Terms ◽  
Topological Crystalline Insulators

Abstract Manipulation of electronic and magnetic properties of topological materials is a topic of much interest in spintronic and valleytronic applications. Perturbation tuning of multiple Dirac cones on the (001) surface of topological crystalline insulators (TCIs) is also a related topic of growing interest. Here we show the numerical evidence for the ferroelectric structural distortion effects on the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between two magnetic impurity moments on the SnTe (001) and related alloys. The mirror symmetry breaking between Dirac cones induced by the ferroelectric distortion could be divided into various possible configurations including the isotropically gapped, coexistence of gapless and gapped, and anisotropically gapped phases. Based on the retarded perturbed Green’s functions of the generalized gapped Dirac model, we numerically find the RKKY response for each phase. The distortion-induced symmetry breaking constitutes complex and interesting magnetic responses between magnetic moments compared to the pristine TCIs. In the specific case of coexisted gapless and gapped phases, a nontrivial behavior of the RKKY interaction is observed, which has not been seen in other Dirac materials up until now. For two impurities resided on the same sublattices, depending on the distortion strength, magnetic orders above of a critical impurity separation exhibit irregular ferromagnetic $ antiferromagnetic phase transitions. However, independent ofthe impurity separation and distortion strength, no phase transition emerges for two impurities resided on different sublattices. This essential study sheds light on magnetic properties of Dirac materials with anisotropic mass terms and also makes TCIs applications relatively easy to understand.

scholarly journals Anisotropic ferroelectric distortion effects on the RKKY interaction in topological crystalline insulators

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hosein Cheraghchi ◽  
Mohsen Yarmohammadi
Keyword(s):  
Magnetic Properties ◽  
Symmetry Breaking ◽  
Mirror Symmetry ◽  
Magnetic Moments ◽  
Rkky Interaction ◽  
Topological Materials ◽  
Dirac Materials ◽  
Magnetic Orders ◽  
Mass Terms ◽  
Topological Crystalline Insulators

AbstractManipulation of electronic and magnetic properties of topological materials is a topic of much interest in spintronic and valleytronic applications. Perturbation tuning of multiple Dirac cones on the (001) surface of topological crystalline insulators (TCIs) is also a related topic of growing interest. Here we show the numerical evidence for the ferroelectric structural distortion effects on the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between two magnetic impurity moments on the SnTe (001) and related alloys. The mirror symmetry breaking between Dirac cones induced by the ferroelectric distortion could be divided into various possible configurations including the isotropically gapped, coexistence of gapless and gapped, and anisotropically gapped phases. Based on the retarded perturbed Green’s functions of the generalized gapped Dirac model, we numerically find the RKKY response for each phase. The distortion-induced symmetry breaking constitutes complex and interesting magnetic responses between magnetic moments compared to the pristine TCIs. In the specific case of coexisted gapless and gapped phases, a nontrivial behavior of the RKKY interaction is observed, which has not been seen in other Dirac materials up until now. For two impurities resided on the same sublattices, depending on the distortion strength, magnetic orders above of a critical impurity separation exhibit irregular ferromagnetic ⇔ antiferromagnetic phase transitions. However, independent of the impurity separation and distortion strength, no phase transition emerges for two impurities resided on different sublattices. This essential study sheds light on magnetic properties of Dirac materials with anisotropic mass terms and also makes TCIs applications relatively easy to understand.

Anomalous magnetic moments for uncharmed and charmed baryons

1984 ◽  
Vol 62 (2) ◽  
pp. 123-125
Author(s):  
Ram Sagar ◽  
R. C. Verma
Keyword(s):  
Symmetry Breaking ◽  
Sum Rules ◽  
Magnetic Moments ◽  
Charmed Baryons

We studied anomalous magnetic moments of the baryons using Drell–Hearn sum rules and found that the observed moments agree better in the presence of symmetry breaking effects.

SU(3) symmetry breaking for masses, magnetic moments and sizes of baryons

1992 ◽  
Vol 540 (3-4) ◽  
pp. 461-477 ◽  
Author(s):  
B. Schwesinger ◽  
H. Weigel
Keyword(s):  
Symmetry Breaking ◽  
Magnetic Moments
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