897 research outputs found
Reformulation of Boundary String Field Theory in terms of Boundary State
We reformulate bosonic boundary string field theory in terms of boundary
state. In our formulation, we can formally perform the integration of target
space equations of motion for arbitrary field configurations without assuming
decoupling of matter and ghost. Thus, we obtain the general form of the action
of bosonic boundary string field theory. This formulation may help us to
understand possible interactions between boundary string field theory and the
closed string sector.Comment: 13 page
SCUBA - A submillimetre camera operating on the James Clerk Maxwell Telescope
The Submillimetre Common-User Bolometer Array (SCUBA) is one of a new
generation of cameras designed to operate in the submillimetre waveband. The
instrument has a wide wavelength range covering all the atmospheric
transmission windows between 300 and 2000 microns. In the heart of the
instrument are two arrays of bolometers optimised for the short (350/450
microns) and long (750/850 microns) wavelength ends of the submillimetre
spectrum. The two arrays can be used simultaneously, giving a unique
dual-wavelength capability, and have a 2.3 arc-minute field of view on the sky.
Background-limited performance is achieved by cooling the arrays to below 100
mK. SCUBA has now been in active service for over a year, and has already made
substantial breakthroughs in many areas of astronomy. In this paper we present
an overview of the performance of SCUBA during the commissioning phase on the
James Clerk Maxwell Telescope (JCMT).Comment: 14 pages, 13 figures (1 JPEG), Proc SPIE vol 335
Correction: The Attitudes to Ageing Questionnaire: Mokken Scaling Analysis
This is the final version. Available from Public Library of Science via the DOI in this record
Using participatory methods to design an mHealth intervention for a low income country, a case study in Chikwawa, Malawi
This research was conducted by the Scotland Chikwawa Health Initiative. We would like to thank Sothin Ziba and Rossanie Daudi for their contribution to the facilitation of the focus group discussions. This study was funded by the Scottish Government grant MW22.Peer reviewedPublisher PD
Barriers to Pregnancy Spacing in Women Living with HIV: A Series of Informational Interviews
For reproductive-age women living with HIV, birth spacing allows for optimization of maternal health and viral suppression to prevent mother-to-child transmission of HIV. We conducted semi-structured informational interviews to explore use of contraception for birth spacing. Interviews were transcribed and analyzed. Audio files were reviewed to capture non-explicit data. We interviewed 18 multiparous HIV positive women. All described experiences with at least one contraceptive method. Six themes emerged: Burden of contraception, Failure of birth control, Impact of youth and lack of life experience, Community beliefs about birth control, Lack of partner cooperation, and Altruism. Women viewed birth spacing favorably. Young age at first delivery, contraceptive side effects, non-adherence to short-acting methods, lack of partner cooperation, and prior contraceptive failure were identified as barriers to ideal birth spacing. Additional outreach is needed in women living with HIV to overcome barriers to planned pregnancy and birth spacing
The Boundary State Formalism and Conformal Invariance in Off-shell String Theory
We present a generalization of the boundary state formalism for the bosonic
string that allows us to calculate the overlap of the boundary state with
arbitrary closed string states. We show that this generalization exactly
reproduces world-sheet sigma model calculations, thus giving the correct
overlap with both on- and off-shell string states, and that this new boundary
state automatically satisfies the requirement for integrated vertex operators
in the case of non-conformally invariant boundary interactions.Comment: 19 pages, 0 figure
Behaviour of three charged particles on a plane under perpendicular magnetic field
We consider the problem of three identical charged particles on a plane under
a perpendicular magnetic field and interacting through Coulomb repulsion. This
problem is treated within Taut's framework, in the limit of vanishing center of
mass vector , which corresponds to the strong magnetic
field limit, occuring for example in the Fractional Quantum Hall Effect. Using
the solutions of the biconfluent Heun equation, we compute the eigenstates and
show that there is two sets of solutions. The first one corresponds to a system
of three independent anyons which have their angular momenta fixed by the value
of the magnetic field and specified by a dimensionless parameter , the ratio of , the magnetic length, over , the Bohr
radius. This anyonic character, consistent with quantum mechanics of identical
particles in two dimensions, is induced by competing physical forces. The
second one corresponds to the case of the Landau problem when .
Finally we compare these states with the quantum Hall states and find that the
Laughlin wave functions are special cases of our solutions under certains
conditions.Comment: 15 pages, 3 figures, Accepeted in JP
No-Boundary Theta-Sectors in Spatially Flat Quantum Cosmology
Gravitational theta-sectors are investigated in spatially locally homogeneous
cosmological models with flat closed spatial surfaces in 2+1 and 3+1 spacetime
dimensions. The metric ansatz is kept in its most general form compatible with
Hamiltonian minisuperspace dynamics. Nontrivial theta-sectors admitting a
semiclassical no-boundary wave function are shown to exist only in 3+1
dimensions, and there only for two spatial topologies. In both cases the
spatial surface is nonorientable and the nontrivial no-boundary theta-sector
unique. In 2+1 dimensions the nonexistence of nontrivial no-boundary
theta-sectors is shown to be of topological origin and thus to transcend both
the semiclassical approximation and the minisuperspace ansatz. Relation to the
necessary condition given by Hartle and Witt for the existence of no-boundary
theta-states is discussed.Comment: 30 p
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