1,097 research outputs found
Lepton Flavour Violating top decays at the LHC
We consider lepton flavour violating decays of the top quark, mediated by
four-fermion operators. We compile constraints on a complete set of
SU(3)*U(1)-invariant operators, arising from their loop contributions to rare
decays and from HERA's single top search. The bounds on e-mu flavour change are
more restrictive than l-tau; nonetheless the top could decay to a jet with a branching ratio of order . We estimate that the
currently available LHC data (20 inverse-fb at 8 TeV) could be sensitive to
+ jet) , and extrapolate that 100
inverse-fb at 13 TeV could reach a sensitivity of .Comment: 10 pages + Appendice
Dark soliton in a disorder potential
We consider dark soliton in a Bose-Einstein condensate in the presence of a
weak disorder potential. Deformation of the soliton shape is analyzed within
the Bogoliubov approach and by employing expansion in eigenstates of the
P\"oschl-Teller Hamiltonian. Comparison of the results with the numerical
simulations indicates that the linear response analysis reveals good agreement
even if the strength of the disorder is of the order of the chemical potential
of the system. In the second part of the paper we concentrate on quantum nature
of the dark soliton and demonstrate that the soliton may reveal Anderson
localization in the presence of a disorder. The Anderson localized soliton may
decay due to quasi-particle excitations induced by the disorder. However, we
show that the corresponding lifetime is much longer than condensate lifetime in
a typical experiment.Comment: 10 pages, 3 figures, version accepted for publication in Phys. Rev.
PARTNERING TO IMPROVE PATIENT OUTCOMES: A QUALITATIVE STUDY OF ADULT PATIENT EXPERIENCES WITH ORTHOPEDIC SURGICAL CARE
The purpose of this study was to explore adult orthopedic surgical patient experiences during their preoperative, perioperative and postoperative care; utilizing the results to discuss specific interactions in care that produced positive or negative outcomes. Partnering with patients to understand shared decision making and patient centered care has been previously researched in literature, and continued research is key to discover effective care practices. The Centers for Disease Control and National Center for Health Statistics (2015) reports total knee and hip joint replacement surgeries of more than one million yearly. The large patient population magnifies the need to understand patient experiences during their orthopedic surgical care and is essential to guide improvements that encourage the patient-healthcare provider partnership. This researcher utilized a phenomenological qualitative design to collect data in a semi structured, topic guided, audio recorded interview until saturation was achieved. Qualitative content analysis was utilized to identify unit meanings
, codes, and themes using the experiences of the 10 study participants. All of the participants had either total knee arthroplasty or total hip arthroplasty at Premier Surgical Institute in Galena Kansas between September 2014 and December 2014, were English speaking and understanding, cognitively intact, and able to meet for the audio recorded interview. A letter of invitation was mailed to 150 potential study participants whom met the criteria, with 10 patients consenting to participate. Four main themes developed that influenced the patient experience and affected outcomes: healthcare provider attentiveness, patient education, patient need for control, and consideration of the patient’s whole life experiences
Driven Rydberg atoms reveal quartic level repulsion
The dynamics of Rydberg states of a hydrogen atom subject simultaneously to
uniform static electric field and two microwave fields with commensurate
frequencies is considered in the range of small fields amplitudes. In the
certain range of the parameters of the system the classical secular motion of
the electronic ellipse reveals chaotic behavior. Quantum mechanically, when the
fine structure of the atom is taken into account, the energy level statistics
obey predictions appropriate for the symplectic Gaussian random matrix
ensemble.Comment: 4 pages, 3 figures, accepted for publication in Phys. Rev. Let
Many-body Anderson localization in one dimensional systems
We show, using quasi-exact numerical simulations, that Anderson localization
of one-dimensional particles in a disordered potential survives in the presence
of attractive interaction between particles. The localization length of the
composite particle can be computed analytically for weak disorder and is in
good agreement with the quasi-exact numerical observations using Time Evolving
Block Decimation. Our approach allows for simulation of the entire experiment
including the final measurement of all atom positions.Comment: 12pp, 5 fig, version accepted in NJ
Self-localized impurities embedded in a one dimensional Bose-Einstein condensate and their quantum fluctuations
We consider the self-localization of neutral impurity atoms in a
Bose-Einstein condensate in a 1D model. Within the strong coupling approach, we
show that the self-localized state exhibits parametric soliton behavior. The
corresponding stationary states are analogous to the solitons of non-linear
optics and to the solitonic solutions of the Schroedinger-Newton equation
(which appears in models that consider the connection between quantum mechanics
and gravitation). In addition, we present a Bogoliubov-de-Gennes formalism to
describe the quantum fluctuations around the product state of the strong
coupling description. Our fluctuation calculations yield the excitation
spectrum and reveal considerable corrections to the strong coupling
description. The knowledge of the spectrum allows a spectroscopic detection of
the impurity self-localization phenomenon.Comment: 7 pages, 5 figure
Structure and Evolution of Giant Cells in Global Models of Solar Convection
The global scales of solar convection are studied through three-dimensional
simulations of compressible convection carried out in spherical shells of
rotating fluid which extend from the base of the convection zone to within 15
Mm of the photosphere. Such modelling at the highest spatial resolution to date
allows study of distinctly turbulent convection, revealing that coherent
downflow structures associated with giant cells continue to play a significant
role in maintaining the strong differential rotation that is achieved. These
giant cells at lower latitudes exhibit prograde propagation relative to the
mean zonal flow, or differential rotation, that they establish, and retrograde
propagation of more isotropic structures with vortical character at mid and
high latitudes. The interstices of the downflow networks often possess strong
and compact cyclonic flows. The evolving giant-cell downflow systems can be
partly masked by the intense smaller scales of convection driven closer to the
surface, yet they are likely to be detectable with the helioseismic probing
that is now becoming available. Indeed, the meandering streams and varying
cellular subsurface flows revealed by helioseismology must be sampling
contributions from the giant cells, yet it is difficult to separate out these
signals from those attributed to the faster horizontal flows of
supergranulation. To aid in such detection, we use our simulations to describe
how the properties of giant cells may be expected to vary with depth, how their
patterns evolve in time, and analyze the statistical features of correlations
within these complex flow fields.Comment: 22 pages, 16 figures (color figures are low res), uses emulateapj.cls
Latex class file, Results shown during a Press release at the AAS meeting in
June 2007. Submitted to Ap
Non-resonant driving of H atom with broken time-reversal symmetry
The dynamics of atomic hydrogen placed in a static electric field and
illuminated by elliptically polarized microwaves is studied in the range of
small field amplitudes where perturbation calculations are applicable. For a
general configuration of the fields any generalized time-reversal symmetry is
broken and, as the classical dynamics is chaotic, the level statistics obeys
the random matrices prediction of Gaussian unitary ensemble.Comment: 4 pages, 2 figures, accepted for publication in J. Phys.
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