5,280 research outputs found
Feshbach resonant scattering of three fermions in one-dimensional wells
We study the weak-tunnelling limit for a system of cold 40K atoms trapped in
a one-dimensional optical lattice close to an s-wave Feshbach resonance. We
calculate the local spectrum for three atoms at one site of the lattice within
a two-channel model. Our results indicate that, for this one-dimensional
system, one- and two-channel models will differ close to the Feshbach
resonance, although the two theories would converge in the limit of strong
Feshbach coupling. We also find level crossings in the low-energy spectrum of a
single well with three atoms that may lead to quantum phase transition for an
optical lattice of many wells. We discuss the stability of the system to a
phase with non-uniform density.Comment: 10 pages, 5 figure
Quantum and Classical in Adiabatic Computation
Adiabatic transport provides a powerful way to manipulate quantum states. By
preparing a system in a readily initialised state and then slowly changing its
Hamiltonian, one may achieve quantum states that would otherwise be
inaccessible. Moreover, a judicious choice of final Hamiltonian whose
groundstate encodes the solution to a problem allows adiabatic transport to be
used for universal quantum computation. However, the dephasing effects of the
environment limit the quantum correlations that an open system can support and
degrade the power of such adiabatic computation. We quantify this effect by
allowing the system to evolve over a restricted set of quantum states,
providing a link between physically inspired classical optimisation algorithms
and quantum adiabatic optimisation. This new perspective allows us to develop
benchmarks to bound the quantum correlations harnessed by an adiabatic
computation. We apply these to the D-Wave Vesuvius machine with revealing -
though inconclusive - results
Pfaffian-like ground states for bosonic atoms and molecules in one-dimensional optical lattices
We study ground states and elementary excitations of a system of bosonic
atoms and diatomic Feshbach molecules trapped in a one-dimensional optical
lattice using exact diagonalization and variational Monte Carlo methods. We
primarily study the case of an average filling of one boson per site. In
agreement with bosonization theory, we show that the ground state of the system
in the thermodynamic limit corresponds to the Pfaffian-like state when the
system is tuned towards the superfluid-to-Mott insulator quantum phase
transition. Our study clarifies the possibility of the creation of exotic
Pfaffian-like states in realistic one-dimensional systems. We also present
preliminary evidence that such states support non-Abelian anyonic excitations
that have potential application for fault-tolerant topological quantum
computation.Comment: 10 pages, 10 figures. Matching the version published Phys.Rev.
Patients' preferences for adjuvant endocrine therapy in early breast cancer: what makes it worthwhile?
Adjuvant endocrine therapy improves recurrence and survival rates, but has side effects and is inconvenient. The aim of this study was to determine the preferences of premenopausal women who had adjuvant endocrine therapy in a randomised trial. In all, 85 (or eighty-five) women completed semistructured interviews 6–30 months after finishing adjuvant endocrine therapy. Hypothetical scenarios based on known potential survival times (5 or 15 years) and rates (60% or 80% at 5 years) without adjuvant endocrine therapy were used to determine the smallest gains women judged necessary to make their adjuvant endocrine therapy worthwhile. Although a third of the women considered gains of 1% in survival rates or 6 months in survival times sufficient to make their adjuvant endocrine therapy worthwhile, more than half the women required gains of at least 5% in survival rates or 3 years in survival time as necessary to make adjuvant endocrine therapy worthwhile. Larger benefits were required by women who had longer treatment, worse side effects, and by those who were treated with goserelin alone. The route of administration (tablet vs injection) did not affect preferences and some women judged small benefits sufficient to make their adjuvant endocrine therapy worthwhile, but many women required larger benefits than their counterparts in similar studies of preferences for adjuvant chemotherapy
High-Resolution, Wide-Field Imaging of the Galactic Center Region at 330 MHz
We present a wide field, sub-arcminute resolution VLA image of the Galactic
Center region at 330 MHz. With a resolution of ~ 7" X 12" and an RMS noise of
1.6 mJy/beam, this image represents a significant increase in resolution and
sensitivity over the previously published VLA image at this frequency. The
improved sensitivity has more than tripled the census of small diameter sources
in the region, has resulted in the detection of two new Non Thermal Filaments
(NTFs), 18 NTF candidates, 30 pulsar candidates, reveals previously known
extended sources in greater detail, and has resulted in the first detection of
Sagittarius A* in this frequency range.
A version of this paper containing full resolution images may be found at
http://lwa.nrl.navy.mil/nord/AAAB.pdf.Comment: Astronomical Journal, Accepted 62 Pages, 21 Figure
GMRT Observations of NGC 3079
We present new observations at three frequencies (326 MHz, 615 MHz, and 1281
MHz) of the radio lobe spiral galaxy, NGC 3079, using the Giant Metrewave Radio
Telescope. These observations are consistent with previous data obtained at
other telescopes and reveal the structure of the nuclear radio lobes in
exquisite detail. In addition, new features are observed, some with HI
counterparts, showing broad scale radio continuum emission and extensions. The
galaxy is surrounded by a radio halo that is at least 4.8 kpc in height. Two
giant radio extensions/loops are seen on either side of the galaxy out to
11 kpc from the major axis, only slightly offset from the direction of
the smaller nuclear radio lobes. If these are associated with the nuclear
outflow, then the galaxy has experienced episodic nuclear activity. Emission
along the southern major axis suggests motion through a local IGM (not yet
detected) and it may be that NGC 3079 is itself creating this local
intergalactic gas via outflows. We also present maps of the minimum energy
parameters for this galaxy, including cosmic ray energy density, electron
diffusion length, magnetic field strength, particle lifetime, and power.Comment: 11 pages, 8 figures, 4 tables, accepted for publication in MNRA
Towards domestic financing of national HIV responses lessons learnt from Serbia
This report highlights the efforts of Serbia to continue
funding and implementation of the national HIV
response which had been significantly supported
by the GF from 2003 to 2014 and resulted in an
intensified communication and consultation between
governmental and NGO sector. Serbia has a long
tradition in national HIV programming. There is
clear evidence that the most effective programmes
are those in which civil society's role, engagement in
providing prevention, care and support services for key
populations and PLHIV and established partnership
with other relevant stakeholders are strongest and
equitable. Moreover, interventions should be supported
by enabling legal and policy frameworks. This includes
measures to increase availability and access to different
services and to minimize law enforcement and other
structural barriers. Constant advocacy work with
relevant stakeholders and standardization of services is
also recognized as very important.sch_iihpub4571pu
Towards domestic financing of national HIV responses - lessons learnt from Croatia
This report highlights the efforts of Croatia to
continue funding the national response to HIV/AIDS
that has been significantly augmented by the Global
Fund to Fight HIV/AIDS, Tuberculosis and Malaria
(GF) grant from 2003 to 2006. The GF project was not
only about funding, it was also about mobilization
of different stakeholders, including politicians,
NGOs, health care and other professionals. Croatia
succeeded to maintain a low level HIV epidemic in
the past three decades. However, many challenges
remain. Unfortunately, a low-level epidemic often
means low-level priority in the society and health care
system.sch_iihpub4572pu
Light-year Scale Radio Cores in Four LINER Galaxies
The LINER galaxies NGC 2911, NGC 3079, NGC 3998, and NGC 6500 were observed
at 5 GHz with the European VLBI Network at a resolution of 5 milliarcsecond and
found to possess flat-spectrum, variable, high-brightness temperature ( K) radio cores. These radio characteristics reinforce the view that
these LINERs host central engines associated with active galactic nuclei.Comment: 6 page
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