16,006 research outputs found
CP Violation from 5-dimensional QED
It has been shown that QED in (1+4)-dimensional space-time, with the fifth
dimension compactified on a circle, leads to CP violation (CPV). Depending on
fermionic boundary conditions, CPV may be either explicit (through the
Scherk--Schwarz mechanism), or spontaneous (via the Hosotani mechanism). The
fifth component of the gauge field acquires (at the one-loop level) a non-zero
vacuum expectation value. In the presence of two fermionic fields, this leads
to spontaneous CPV in the case of CP-symmetric boundary conditions.
Phenomenological consequences are illustrated by a calculation of the electric
dipole moment for the fermionic zero-modes.Comment: 11 pages, 2 figure
A Relativistic Description of Gentry's New Redshift Interpretation
We obtain a new expression of the Friedmann-Robertson-Walker metric, which is
an analogue of a static chart of the de Sitter space-time. The reduced metric
contains two functions, and , which are interpreted as,
respectively, the mass function and the gravitational potential. We find that,
near the coordinate origin, the reduced metric can be approximated in a static
form and that the approximated metric function, , satisfies the
Poisson equation. Moreover, when the model parameters of the
Friedmann-Robertson-Walker metric are suitably chosen, the approximated metric
coincides with exact solutions of the Einstein equation with the perfect fluid
matter. We then solve the radial geodesics on the approximated space-time to
obtain the distance-redshift relation of geodesic sources observed by the
comoving observer at the origin. We find that the redshift is expressed in
terms of a peculiar velocity of the source and the metric function, ,
evaluated at the source position, and one may think that this is a new
interpretation of {\it Gentry's new redshift interpretation}.Comment: 11 pages. Submitted to Modern Physics Letters
Universal Properties of Nonlinear Response Functions of Nonequilibrium Steady States
We derive universal properties of nonlinear response functions of
nonequilibrium steady states. In particular, sum rules and asymptotic behaviors
are derived. Their consequences are illustrated for nonlinear optical materials
and nonlinear electrical conductors.Comment: 10 pages, 1 figure; added a few sentences and references to explain
detail
Prediction of Ferromagnetic Ground State of NaCl-type FeN
Ab-initio results for structural and electronic properties of NaCl-type FeN
are presented in a framework of plane-wave and ultrasoft pseudopotentials.
Competition among different magnetic ordering is examined. We find the
ferromagnetic phase stable overall. Stabilization over the unpolarized phase is
obtained by splitting one flat t_2g-type band crossing the Fermi energy. A
comparison with CrN is considered. We find large differences in the properties
of the two systems that can be addressed to the smaller ionicity and
magnetization of FeN.Comment: 5 pages, 4 figures, twocolumn latex style Sentence changed in Section
III line 1
Shape coexistence in Lead isotopes in the interacting boson model with Gogny energy density functional
We investigate the emergence and evolution of shape coexistence in the
neutron-deficient Lead isotopes within the interacting boson model (IBM) plus
configuration mixing with microscopic input based on the Gogny energy density
functional (EDF). The microscopic potential energy surface obtained from the
constrained self-consistent Hartree-Fock-Bogoliubov method employing the
Gogny-D1M EDF is mapped onto the coherent-state expectation value of the
configuration-mixing IBM Hamiltonian. In this way, the parameters of the IBM
Hamiltonian are fixed for each of the three relevant configurations (spherical,
prolate and oblate) associated to the mean field minima. Subsequent
diagonalization of the Hamiltonian provides the excitation energy of the
low-lying states and transition strengths among them. The model predictions for
the level energies and evolving shape coexistence in the considered
Lead chain are consistent both with experiment and with the indications of the
Gogny-EDF energy surfaces.Comment: 12 pages, 6 figures, 1 tabl
Quadrupole Collective Dynamics from Energy Density Functionals: Collective Hamiltonian and the Interacting Boson Model
Microscopic energy density functionals (EDF) have become a standard tool for
nuclear structure calculations, providing an accurate global description of
nuclear ground states and collective excitations. For spectroscopic
applications this framework has to be extended to account for collective
correlations related to restoration of symmetries broken by the static mean
field, and for fluctuations of collective variables. In this work we compare
two approaches to five-dimensional quadrupole dynamics: the collective
Hamiltonian for quadrupole vibrations and rotations, and the Interacting Boson
Model. The two models are compared in a study of the evolution of non-axial
shapes in Pt isotopes. Starting from the binding energy surfaces of
Pt, calculated with a microscopic energy density functional, we
analyze the resulting low-energy collective spectra obtained from the
collective Hamiltonian, and the corresponding IBM-2 Hamiltonian. The calculated
excitation spectra and transition probabilities for the ground-state bands and
the -vibration bands are compared to the corresponding sequences of
experimental states.Comment: 10 pages, 4 figures; to be published in Phys. Rev.
Disintegration of Magnetic Flux in Decaying Sunspots as Observed with the Hinode SOT
Continuous observations of sunspot penumbrae with the Solar Optical Telescope
aboard \textit{Hinode} clearly show that the outer boundary of the penumbra
fluctuates around its averaged position. The penumbral outer boundary moves
inward when granules appear in the outer penumbra. We discover that such
granules appear one after another while moving magnetic features (MMFs) are
separating from the penumbral ``spines'' (penumbral features that have stronger
and more vertical fields than those of their surroundings). These granules that
appear in the outer penumbra often merge with bright features inside the
penumbra that move with the spines as they elongate toward the moat region.
This suggests that convective motions around the penumbral outer boundary are
related to the disintegration of magnetic flux in the sunspot. We also find
that dark penumbral filaments frequently elongate into the moat region in the
vicinity of MMFs that detach from penumbral spines. Such elongating dark
penumbral filaments correspond to nearly horizontal fields extending from the
penumbra. Pairs of MMFs with positive and negative polarities are sometimes
observed along the elongating dark penumbral filaments. This strongly supports
the notion that such elongating dark penumbral filaments have magnetic fields
with a ``sea serpent''-like structure. Evershed flows, which are associated
with the penumbral horizontal fields, may be related to the detachment of the
MMFs from the penumbral spines, as well as to the formation of the MMFs along
the dark penumbral filaments that elongate into the moat region.Comment: Accepted for publication in Ap
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Using Display Energy Certificates to quantify public sector office energy consumption
This paper explores how internal and external characteristics affect energy use in the public sector office stock in England and Wales, using a database of 2,600 Display Energy Certificates (DECs) combined with other sources of disaggregated office information.
The DEC office benchmarks were shown to match the median fossil thermal and electrical consumptions well. Analysis of HVAC, size, occupancy density, building age, location and rateable value were considered. While newer offices were shown to have lower typical fossil-thermal consumption than older offices, this was counterbalanced by higher electrical consumption, resulting in higher typical CO2 emissions. This has implications for the UK's emissions reduction targets for 2050, indicating that while building regulations that focus on thermal performance have been successful, a focus on electrical consumption (both regulated and unregulated) is key.
The results were also compared with existing benchmarks for all UK offices, splitting the sample into four generic types, and compared to a similar smaller study of private offices. This indicated that public offices typically used less energy than the general benchmarks had previously predicted, particularly for prestige offices.This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) funding for Doctoral Training Studentships, and in association with the EPSRC funded 'ReVISIONS' project [grant number EP/F007566/1].This is the final published version. It first appeared at http://dx.doi.org/10.1080/09613218.2014.97541
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