12,333 research outputs found

### Inversion phenomenon and phase diagram of the $S=1/2$ distorted diamond chain with the $XXZ$ interaction anisotropy

We discuss the anisotropies of the Hamiltonian and the wave-function in an
$S=1/2$ distorted diamond chain. The ground-state phase diagram of this model
is investigated using the degenerate perturbation theory up to the first order
and the level spectroscopy analysis of the numerical diagonalization data. In
some regions of the obtained phase diagram, the anisotropy of the Hamiltonian
and that of the wave-function are inverted, which we call inversion phenomenon;
the N\'{e}el phase appears for the XY-like anisotropy and the spin-fluid phase
appears for the Ising-like anisotropy. Three key words are important for this
nature, which are frustration, the trimer nature, and the $XXZ$ anisotropy.Comment: 4pages, 10 figures, for proceedings of SPQS 200

### Two-neutron transfer reactions and shape phase transitions in the microscopically-formulated interacting boson model

Two-neutron transfer reactions are studied within the interacting boson model
based on the nuclear energy density functional theory. Constrained
self-consistent mean-field calculations with the Skyrme energy density
functional are performed to provide microscopic input to completely determine
the Hamiltonian of the IBM. Spectroscopic properties are calculated only from
the nucleonic degrees of freedom. This method is applied to study the $(t,p)$
and $(p,t)$ transfer reactions in the assorted set of rare-earth nuclei
$^{146-158}$Sm, $^{148-160}$Gd, and $^{150-162}$Dy, where
spherical-to-axially-deformed shape phase transition is suggested to occur at
the neutron number $N\approx 90$. The results are compared with those from the
purely phenomenological IBM calculations, as well as with the available
experimental data. The calculated $(t,p)$ and $(p,t)$ transfer reaction
intensities, from both the microscopic and phenomenological IBM frameworks,
signal the rapid nuclear structural change at particular nucleon numbers.Comment: 12 pages, 12 figures, 2 table

### Berezinskii-Kosterlitz-Thouless transitions in the six-state clock model

Classical 2D clock model is known to have a critical phase with
Berezinskii-Kosterlitz-Thouless(BKT) transitions. These transitions have
logarithmic corrections which make numerical analysis difficult. In order to
resolve this difficulty, one of the authors has proposed the method called
level spectroscopy, which is based on the conformal field theory. We extend
this method to the multi-degenerated case. As an example, we study the
classical 2D 6-clock model which can be mapped to the quantum self-dual 1D
6-clock model. Additionally, we confirm that the self-dual point has a precise
numerical agreement with the analytical result, and we argue the degeneracy of
the excitation states at the self-dual point from the effective field
theoretical point of view.Comment: 18pages, 7figure

### Shape-phase transitions in odd-mass $\gamma$-soft nuclei with mass $A\approx 130$

Quantum phase transitions between competing equilibrium shapes of nuclei with
an odd number of nucleons are explored using a microscopic framework of nuclear
energy density functionals and a particle-boson core coupling model. The boson
Hamiltonian for the even-even core nucleus, as well as the spherical
single-particle energies and occupation probabilities of unpaired nucleons, are
completely determined by a constrained self-consistent mean-field calculation
for a specific choice of the energy density functional and pairing interaction.
Only the strength parameters of the particle-core coupling have to be adjusted
to reproduce a few empirical low-energy spectroscopic properties of the
corresponding odd-mass system. The model is applied to the odd-A Ba, Xe, La and
Cs isotopes with mass $A\approx 130$, for which the corresponding even-even Ba
and Xe nuclei present a typical case of $\gamma$-soft nuclear potential. The
theoretical results reproduce the experimental low-energy excitation spectra
and electromagnetic properties, and confirm that a phase transition between
nearly spherical and $\gamma$-soft nuclear shapes occurs also in the odd-A
systems.Comment: 13 pages, 15 figures, 9 table

### Signatures of shape phase transitions in odd-mass nuclei

Quantum phase transitions between competing ground-state shapes of atomic
nuclei with an odd number of protons or neutrons are investigated in a
microscopic framework based on nuclear energy density functional theory and the
particle-plus-boson-core coupling scheme. The boson-core Hamiltonian, as well
as the single-particle energies and occupation probabilities of the unpaired
nucleon, are completely determined by constrained self-consistent mean-field
calculations for a specific choice of the energy density functional and paring
interaction, and only the strength parameters of the particle-core coupling are
adjusted to reproduce selected spectroscopic properties of the odd-mass system.
We apply this method to odd-A Eu and Sm isotopes with neutron number $N \approx
90$, and explore the influence of the single unpaired fermion on the occurrence
of a shape phase transition. Collective wave functions of low-energy states are
used to compute quantities that can be related to quantum order parameters:
deformations, excitation energies, E2 transition rates and separation energies,
and their evolution with the control parameter (neutron number) is analysed.Comment: 15 pages, 13 figures; Accepted for publication in Phys. Rev.

### A Gauge Mediation Model of Dynamical Supersymmetry Breaking without Color Instability

We construct a gauge mediation model of dynamical supersymmetry breaking
(DSB) based on a vector-like gauge theory, in which there is a unique
color-preserving true vacuum. The DSB scale $\Lambda/4\pi$ turns out to be as
high as $\Lambda/4\pi \simeq 10^{8-9} GeV$, since the transmission of the DSB
effects to the standard model sector is completed through much higher loops.
This model is perfectly natural and phenomenologically consistent. We also
stress that the dangerous D-term problem for the messenger U(1)_m is
automatically solved by a charge conjugation symmetry in the vector-like gauge
theory.Comment: 11 pages, Late

### Magnetization Plateau of an S=1 Frustrated Spin Ladder

We study the magnetization plateau at 1/4 of the saturation magnetization of
the S=1 antiferromagnetic spin ladder both analytically and numerically, with
the aim of explaining recent experimental results on BIP-TENO by Goto et al. We
propose two mechanisms for the plateau formation and clarify the plateau phase
diagram on the plane of the coupling constants between spins

### Cosmological Constants as Messenger between Branes

We present a supersymmetry-breaking scenario in which both the breaking in
the hidden sector with no-scale type supergravity and that in the observable
sector with gauge mediation are taken into account. The breaking scales in the
hidden and observable sectors are related through the vanishing condition of
the cosmological constant with a brane-world picture in mind. Suppressing
flavor-changing neutral currents, we can naturally obtain the gravitino,
Higgs(ino), and soft masses of the electroweak scale.Comment: 7 pages, Late

### Differences on social acceptance of humanoid robots between Japan and the UK

Held at AISB'15 ConventionTo validate a questionnaire for measuring people's acceptance of humanoid robots in cross-cultural research (the Frankenstein Syndrome Questionnaire: FSQ), an online survey was conducted in both the UK and Japan including items on perceptions of the relation to the family and commitment to religions, and negative attitudes toward robots (the NARS). The results suggested that 1) the correlations between the FSQ subscale scores and NARS were sufficient, 2) the UK people felt more negative toward humanoid robots than did the Japanese people, 3) young UK people had more expectation for humanoid robots, 4) relationships between social acceptance of humanoid robots and negative attitudes toward robots in general were different between the nations and generations, and 5) there were no correlations between the FSQ subscale scores, and perception of the relation to the family and commitment to religions.Final Accepted Versio

### Microscopic analysis of the octupole phase transition in Th isotopes

A shape phase transition between stable octupole deformation and octupole
vibrations in Th nuclei is analyzed in a microscopic framework based on nuclear
density functional theory. The relativistic functional DD-PC1 is used to
calculate axially-symmetric quadrupole-octupole constrained energy surfaces.
Observables related to order parameters are computed using an interacting-boson
Hamiltonian, with parameters determined by mapping the microscopic energy
surfaces to the expectation value of the Hamiltonian in the boson condensate.
The systematics of constrained energy surfaces and low-energy excitation
spectra point to the occurrence of a phase transition between octupole-deformed
shapes and shapes characterized by octupole-soft potentials.Comment: 6 pages, 5 figures, accepted for publication in Physical Review C,
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