SYMMETRY BREAKING PHENOMENA IN MESOSCOPIC SYSTEMS: QUANTUM DOTS AND ROTATING NUCLEI

2009 ◽  
Vol 18 (04) ◽  
pp. 1014-1021
Author(s):  
R. G. NAZMITDINOV ◽  
A. PUENTE
Keyword(s):  
Quantum Dots ◽  
Symmetry Breaking ◽  
Rotational Symmetry ◽  
Random Phase ◽  
Mean Field ◽  
Rotating Frame ◽  
Octupole Deformation ◽  
The Mean ◽  
Symmetry Breaking Phenomena ◽  
Rotating Nuclei

A brief description of excited and ground states in two-dimensional quantum dots and rotating nuclei is presented within a mean field approach and a random-phase approximation (RPA). We discuss the procedure to restore the rotational symmetry broken at the mean field, which can be extended for other symmetry breaking cases. We propose to consider a disappearance of collective excitations in the rotating frame as a manifestation of symmetry breaking phenomena of the rotating mean field. In particular, we demonstrate that the disappearance of a collective octupole mode in the rotating frame in 162 Yb gives rise to the nonaxial octupole deformation.

CURRENTS, SPIN DENSITIES AND MEAN-FIELD FORM FACTORS IN ROTATING NUCLEI: A SEMI-CLASSICAL APPROACH

2004 ◽  
Vol 13 (01) ◽  
pp. 225-233 ◽  
Author(s):  
J. BARTEL ◽  
K. BENCHEIKH ◽  
P. QUENTIN
Keyword(s):  
Mean Field ◽  
Form Factors ◽  
Spin Vector ◽  
Self Consistent ◽  
Field Form ◽  
Local Densities ◽  
The Mean ◽  
Self Consistency ◽  
Spin Densities ◽  
Rotating Nuclei

We present self-consistent semi-classical local densities characterising the structure of rotating nuclei. A particular emphasis is put on those densities which are generated by the breaking of time-reversal symmetry through the cranking piece of the Routhian, namely the current density and the spin vector density. Our approach which is based on the Extended-Thomas-Fermi method goes beyond the Inglis cranking approach and contains naturally the Thouless-Valatin self-consistency terms expressing the response of the mean field to the time-odd part of the density matrix.

scholarly journals Symmetry Breaking in Interacting Ring-Shaped Superflows of Bose–Einstein Condensates

Symmetry ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1312 ◽  
Author(s):  
Artem Oliinyk ◽  
Igor Yatsuta ◽  
Boris Malomed ◽  
Alexander Yakimenko
Keyword(s):  
Symmetry Breaking ◽  
Rotational Symmetry ◽  
Mean Field ◽  
Spontaneous Breaking ◽  
Persistent Currents ◽  
Mean Field Model ◽  
Final State ◽  
Double Ring ◽  
Angular Momenta ◽  
Bose Einstein

We demonstrate that the evolution of superflows in interacting persistent currents of ultracold gases is strongly affected by symmetry breaking of the quantum vortex dynamics. We study counter-propagating superflows in a system of two parallel rings in regimes of weak (a Josephson junction with tunneling through the barrier) and strong (rings merging across a reduced barrier) interactions. For the weakly interacting toroidal Bose–Einstein condensates, formation of rotational fluxons (Josephson vortices) is associated with spontaneous breaking of the rotational symmetry of the tunneling superflows. The influence of a controllable symmetry breaking on the final state of the merging counter-propagating superflows is investigated in the framework of a weakly dissipative mean-field model. It is demonstrated that the population imbalance between the merging flows and the breaking of the underlying rotational symmetry can drive the double-ring system to final states with different angular momenta.

σ AND ω, WITH ∆-BARYON, AT HIGH TEMPERATURE

1996 ◽  
Vol 05 (03) ◽  
pp. 511-520
Author(s):  
ABHIJIT BHATTACHARYYA
Keyword(s):  
High Temperature ◽  
Temperature Dependence ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Mean Field ◽  
Meson Mass ◽  
Phase Approximation ◽  
Effective Masses ◽  
The Mean ◽  
Walecka Model

The temperature dependence of σ and ω meson effective masses due to the presence of Δ-baryon has been studied. Starting from the Walecka model, containing both nucleon and Δ, the temperature dependence of effective masses of nucleon and Δ have been calculated at the Mean Field (MF) level. These results have been used to calculate the contribution to the effective masses of σ and ω from both [Formula: see text]- and [Formula: see text]-loops in Random Phase Approximation (RPA). The results are quite interesting. The σ-meson mass increases due to the [Formula: see text] loop whereas it decreases due to [Formula: see text]-loop with temperature. Further, the change in σ-meson mass due to [Formula: see text]-loop is much more compared to that due to [Formula: see text]-loop. For the ω-meson, both the loops are responsible for the increase in mass with temperature.

scholarly journals ISOSPIN MIXING OF ISOSPIN-PROJECTED SLATER DETERMINANTS: FORMALISM AND PRELIMINARY APPLICATIONS

2009 ◽  
Vol 18 (04) ◽  
pp. 958-964 ◽  
Author(s):  
M. RAFALSKI ◽  
W. SATUŁA ◽  
J. DOBACZEWSKI
Keyword(s):  
Symmetry Breaking ◽  
Harmonic Oscillator ◽  
Mean Field ◽  
Isospin Symmetry ◽  
Harmonic Oscillator Basis ◽  
Field Approach ◽  
Mixing Parameter ◽  
Oscillator Basis ◽  
Isospin Symmetry Breaking ◽  
The Mean

We report on the development of a new theoretical tool that allows for isospin projection of Slater determinants and we present its first applications. In particular, we determine the isospin mixing in ground states of N = Z nuclei and discuss its dependence on the size of the harmonic-oscillator basis used in the calculations. We also discuss the unphysical contribution to the isospin mixing caused by the spurious isospin-symmetry breaking inherent to the mean-field approach. We show that these contributions may be as large as 30% of the value of the isospin-mixing parameter.

scholarly journals Formalizing the gene centered view of evolution

1999 ◽  
Vol 02 (03) ◽  
pp. 277-281 ◽  
Author(s):  
Yaneer Bar-Yam
Keyword(s):  
Symmetry Breaking ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Trait Divergence ◽  
The Mean ◽  
Dynamic Version ◽  
Evolving Populations

A historical dispute in the conceptual underpinnings of evolution is the validity of the gene centered view of evolution (Dawkins, 1989; Sober and Lewontin, 1982). We transcend this debate by formalizing the gene centered view as a dynamic version of the mean field approximation. This establishes the conditions under which it is applicable and when it is not. In particular, it breaks down for trait divergence which corresponds to symmetry breaking in evolving populations.

scholarly journals CLUSTER RADIOACTIVITY OF TH ISOTOPES IN THE MEAN-FIELD HFB THEORY

2008 ◽  
Vol 17 (01) ◽  
pp. 204-211 ◽  
Author(s):  
L. M. ROBLEDO ◽  
M. WARDA
Keyword(s):  
Experimental Data ◽  
Symmetry Breaking ◽  
Quadrupole Moment ◽  
Mean Field ◽  
Reflection Symmetry ◽  
Fission Process ◽  
Cluster Radioactivity ◽  
The Mean ◽  
The Masses ◽  
Asymmetric Fission

Cluster radioactivity is described as a very mass asymmetric fission process. The reflection symmetry breaking octupole moment has been used in a mean field HFB theory as leading coordinate instead of the quadrupole moment usually used in standard fission calculations. The procedure has been applied to the study of the "very mass asymmetric fission barrier" of several even-even Thorium isotopes. The masses of the emitted clusters as well as the corresponding half-lives have been evaluated on those cases where experimental data exist.

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