1,674 research outputs found
The supercharge and superconformal symmetry for N=1 supersymmetric quantum mechanics
The superspace Lagrangian formulation of N=1 supersymmetric quantum mechanics
is presented. The general Lagrangian constructed out of chiral and antichiral
supercoordinates containing up to two derivatives and with a canonically
normalized kinetic energy term describes the motion of a nonrelativistic spin
1/2 particle with Land\'e g-factor 2 moving in two spatial dimensions under the
influence of a static but spatially dependent magnetic field. Noether's theorem
is derived for the general case and is used to construct superspace dependent
charges whose lowest components give the superconformal generators. The
supercoordinate of charges containing an R symmetry charge, the supersymmetry
charges and the Hamiltonian are combined to form a supercharge supercoordinate.
Superconformal Ward identities for the quantum effective action are derived
from the conservation equations and the source of potential symmetry breaking
terms are identified.Comment: 59 pages, LaTe
Територія і кордон як фактори формування етнічної ідентичності (за матеріалами досліджень прикордонних територій Брянської області)
В статье на основе современного исследования, проведённого среди населения Брянской области России, которое проживает на пограничье с Беларусью и Украиной, отражён процесс формирования этнической идентичности у местных подростков (16–18 лет). Также проанализирован ряд идентичных критериев, факторов исторического взаимодействия трёх восточнославянских народов в сфере образования, культуры, языка, конфессиональной принадлежности и т. п.Based on the modern investigation amongst the Russian Briansk Oblast people living on the frontier with Byelorussia and Ukraine there is an elucidation of the ethnical identity formative process amidst the local teenagers (16–18-year-old). Moreover analysed is a number of the identical criteria and factors of the historical interrelations of the three Eastern Slavonic nations in the fields of education, culture, language, confession, etc
Influences on and patterns in total gaseous mercury (TGM) at Harwell, England
Total gaseous mercury (TGM) was monitored during 2013 at the rural monitoring site, Harwell, England using the Tekran 2537A monitoring system. Average TGM for the year was 1.45 ± 0.24 ng m−3. This is comparable to other northern hemisphere studies, but on average 0.5 ng m−3 higher than at its sister monitoring station at Auchencorth Moss, Scotland, but 14% lower than that found in a similar study at the same location of 1.68 ng m−3 in 1995/6. Using wind sector analysis we show the important influence of local emissions, with our data showing that the largest influence on TGM observed is that of the adjacent Science & Innovation campus, making the site more a ‘suburban background’. By using co-located measurements of black carbon and sulphur dioxide as tracers, we present an initial investigation into the impact of the closure of Didcot A coal fired power station, which ceased operating in March 2013. Further analysis using air mass back trajectories shows the long-range contribution to TGM from continental Europe, and that the lowest levels are associated with marine air masses from the west
Non-topological Domain Walls in a Model with Broken Supersymmetry
We study non-topological, charged planar walls (Q-walls) in the context of a
particle physics model with supersymmetry broken by low-energy gauge mediation.
Analytical properties are derived within the flat-potential approximation for
the flat-direction raising potential, while a numerical study is performed
using the full two-loop supersymmetric potential. We analyze the energetics of
finite-size Q-walls and compare them to Q-balls, non-topological solitons
possessing spherical symmetry and arising in the same supersymmetric model.
This allow us to draw a phase diagram in the charge-transverse length plane,
which shows a region where Q-wall solutions are more stable than Q-balls.Comment: Some discussion about the phase diagram added. To appear on the
journal "Communications in Theoretical Physics
The Effective Action For Brane Localized Gauge Fields
The low energy effective action including gauge field degrees of freedom on a
non-BPS p=2 brane embedded in a N=1, D=4 target superspace is obtained through
the method of nonlinear realizations of the associated super-Poincare
symmetries. The invariant interactions of the gauge fields and the brane
excitation modes corresponding to the Nambu-Goldstone degrees of freedom
resulting from the broken space translational symmetry and the target space
supersymmetries are determined. Brane localized matter field interactions with
the gauge fields are obtained through the construction of the combined gauge
and super-Poincare covariant derivatives for the matter fields.Comment: 12 pages, no figure
Random Exchange Disorder in the Spin-1/2 XXZ Chain
The one-dimensional XXZ model is studied in the presence of disorder in the
Heisenberg Exchange Integral. Recent predictions obtained from renormalization
group calculations are investigated numerically using a Lanczos algorithm on
chains of up to 18 sites. It is found that in the presence of strong
X-Y-symmetric random exchange couplings, a ``random singlet'' phase with
quasi-long-range order in the spin-spin correlations persists. As the planar
anisotropy is varied, the full zero-temperature phase diagram is obtained and
compared with predictions of Doty and Fisher [Phys. Rev. B {\bf 45 }, 2167
(1992)].Comment: 9 pages + 8 plots appended, RevTex, FSU-SCRI-93-98 and
ORNL/CCIP/93/1
Application of information entropy to nuclei
Shannon's information entropies in position- and momentum- space and their
sum are calculated for various - and - shell nuclei using a
correlated one-body density matrix depending on the harmonic oscillator size
and the short range correlation parameter which originates from a
Jastrow correlation function. It is found that the information entropy sum for
a nucleus depends only on the correlation parameter through the simple
relation , where , and
depend on the mass number . A similar approximate expression
is also valid for the root mean square radius of the nucleus as function of
leading to an approximate expression which connects with the root mean
square radius. Finally, we propose a method to determine the correlation
parameter from the above property of as well as the linear dependence of
on the logarithm of the number of nucleons.Comment: 10 pages, 10 EPS figures, RevTeX, Phys.Rev.C accepted for publicatio
STM characterization of the Si-P heterodimer
We use scanning tunneling microscopy (STM) and Auger electron spectroscopy to
study the behavior of adsorbed phosphine (PH) on Si(001), as a function
of annealing temperature, paying particular attention to the formation of the
Si-P heterodimer. Dosing the Si(001) surface with 0.002 Langmuirs of
PH results in the adsorption of PH (x=2,3) onto the surface and
some etching of Si to form individual Si ad-dimers. Annealing to 350C
results in the incorporation of P into the surface layer to form Si-P
heterodimers and the formation of short 1-dimensional Si dimer chains and
monohydrides. In filled state STM images, isolated Si-P heterodimers appear as
zig-zag features on the surface due to the static dimer buckling induced by the
heterodimer. In the presence of a moderate coverage of monohydrides this static
buckling is lifted, rending the Si-P heterodimers invisible in filled state
images. However, we find that we can image the heterodimer at all H coverages
using empty state imaging. The ability to identify single P atoms incorporated
into Si(001) will be invaluable in the development of nanoscale electronic
devices based on controlled atomic-scale doping of Si.Comment: 6 pages, 4 figures (only 72dpi
Effective spin model for interband transport in a Wannier-Stark lattice system
We show that the interband dynamics in a tilted two-band Bose-Hubbard model
can be reduced to an analytically accessible spin model in the case of resonant
interband oscillations. This allows us to predict the revival time of these
oscillations which decay and revive due to inter-particle interactions. The
presented mapping onto the spin model and the so achieved reduction of
complexity has interesting perspectives for future studies of many-body
systems.Comment: 7 pages, 4 figure
Electronic polarization in pentacene crystals and thin films
Electronic polarization is evaluated in pentacene crystals and in thin films
on a metallic substrate using a self-consistent method for computing charge
redistribution in non-overlapping molecules. The optical dielectric constant
and its principal axes are reported for a neutral crystal. The polarization
energies P+ and P- of a cation and anion at infinite separation are found for
both molecules in the crystal's unit cell in the bulk, at the surface, and at
the organic-metal interface of a film of N molecular layers. We find that a
single pentacene layer with herring-bone packing provides a screening
environment approaching the bulk. The polarization contribution to the
transport gap P=(P+)+(P-), which is 2.01 eV in the bulk, decreases and
increases by only ~ 10% at surfaces and interfaces, respectively. We also
compute the polarization energy of charge-transfer (CT) states with fixed
separation between anion and cation, and compare to electroabsorption data and
to submolecular calculations. Electronic polarization of ~ 1 eV per charge has
a major role for transport in organic molecular systems with limited overlap.Comment: 10 revtex pages, 6 PS figures embedde
- …