152 research outputs found
Conformally invariant supersymmetric field theories on Sp Ă S1 and super p-branes
We construct supersymmetric field theories on Sp Ă S1 for p = 1,âŠ,5. These spaces are the boundaries of the anti-de Sitter space in (p + 2)-dimensions. Thesetheories are invariant under the super extension of the anti-de Sitter group in (p + 2)-dimensions, whose bosonic subalgebra is SO(p + 1,2) asterisk in circle SO(N), for N = 1,2,4,8. The anti-de Sitter group SO(p + 1,2) acts as the conformal group on Sp Ă S1. We conjecture that these theories describe the super p-branes propagating in AdSp + 2 Ă SNâ1. The internal space is always one of the parallelizable spheres, namely S1, S3 or S7
On gravitational dressing of renormalization group beta-functions beyond lowest order of perturbation theory
Based on considerations in conformal gauge I derive up to nextleading order a
relation between the coefficients of beta-functions in 2D renormalizable field
theories before and after coupling to gravity. The result implies a coupling
constant dependence of the ratio of both beta-functions beyond leading order.Comment: DESY 94-?, HU Berlin-IEP-94/21, 9 pages, Late
The Gaugings of Maximal D=6 Supergravity
We construct the most general gaugings of the maximal D=6 supergravity. The
theory is (2,2) supersymmetric, and possesses an on-shell SO(5,5) duality
symmetry which plays a key role in determining its couplings. The field content
includes 16 vector fields that carry a chiral spinor representation of the
duality group. We utilize the embedding tensor method which determines the
appropriate combinations of these vectors that participate in gauging of a
suitable subgroup of SO(5,5). The construction also introduces the magnetic
duals of the 5 two-form potentials and 16 vector fields.Comment: 34 pages, latex, reference added, typo's corrected and minor
improvements mad
Dualisation of Dualities, I
We analyse the global (rigid) symmetries that are realised on the bosonic
fields of the various supergravity actions obtained from eleven-dimensional
supergravity by toroidal compactification followed by the dualisation of some
subset of fields. In particular, we show how the global symmetries of the
action can be affected by the choice of this subset. This phenomenon occurs
even with the global symmetries of the equations of motion. A striking
regularity is exhibited by the series of theories obtained respectively without
any dualisation, with the dualisation of only the Ramond-Ramond fields of the
type IIA theory, with full dualisation to lowest degree forms, and finally for
certain inverse dualisations (increasing the degrees of some forms) to give the
type IIB series. These theories may be called the GL_A, D, E and GL_B series
respectively. It turns out that the scalar Lagrangians of the E series are
sigma models on the symmetric spaces K(E_{11-D})\backslash E_{11-D} (where K(G)
is the maximal compact subgroup of G) and the other three series lead to models
on homogeneous spaces K(G) \backslash G\semi \R^s. These can be understood from
the E series in terms of the deletion of positive roots associated with the
dualised scalars, which implies a group contraction. We also propose a
constrained Lagrangian version of the even dimensional theories exhibiting the
full duality symmetry and begin a systematic analysis of abelian duality
subalgebras.Comment: Latex, 82 pages, minor corrections and references adde
Timelike Boundary Liouville Theory
The timelike boundary Liouville (TBL) conformal field theory consisting of a
negative norm boson with an exponential boundary interaction is considered. TBL
and its close cousin, a positive norm boson with a non-hermitian boundary
interaction, arise in the description of the accumulation point of
minimal models, as the worldsheet description of open string tachyon
condensation in string theory and in scaling limits of superconductors with
line defects. Bulk correlators are shown to be exactly soluble. In contrast,
due to OPE singularities near the boundary interaction, the computation of
boundary correlators is a challenging problem which we address but do not fully
solve. Analytic continuation from the known correlators of spatial boundary
Liouville to TBL encounters an infinite accumulation of poles and zeros. A
particular contour prescription is proposed which cancels the poles against the
zeros in the boundary correlator d(\o) of two operators of weight \o^2 and
yields a finite result. A general relation is proposed between two-point CFT
correlators and stringy Bogolubov coefficients, according to which the
magnitude of d(\o) determines the rate of open string pair creation during
tachyon condensation. The rate so obtained agrees at large \o with a
minisuperspace analysis of previous work. It is suggested that the mathematical
ambiguity arising in the prescription for analytic continuation of the
correlators corresponds to the physical ambiguity in the choice of open string
modes and vacua in a time dependent background.Comment: 28 pages, 1 figure, v2 reference and acknowledgement adde
Epsilon-expansion in quantum field theory in curved spacetime
We discuss epsilon-expansion in curved spacetime for asymptotically free and
asymptotically non-free theories. The esistence of stable and unstable fixed
points is investigated for and SU(2) gauge theory. It is shown that
epsilon-expansion maybe compatible with asymptotic freedom on special solutions
of the RG equations in a special case (supersymmetric theory). Using
epsilon-expansion RG technique the effective Lagrangian for covariantly
constant gauge SU(2) field and effective potential for gauged NJL-model are
found in 4-epsilon- dimensional curved space (in linear curvature
approximation). The curvature- induced phase transitions from symmetric phase
to asymmetric phase (chromomagnetic vacuum and chiral symmetry broken phase,
respectively) are discussed for the above two models.Comment: Latex file, 22 pages, July 1997 preprin
Compactifications with S-Duality Twists
We consider generalised Scherk Schwarz reductions of supergravity and
superstring theories with twists by electromagnetic dualities that are
symmetries of the equations of motion but not of the action, such as the
S-duality of D=4, N=4 super-Yang-Mills coupled to supergravity. The reduction
cannot be done on the action itself, but must be done either on the field
equations or on a duality invariant form of the action, such as one in the
doubled formalism in which potentials are introduced for both electric and
magnetic fields. The resulting theory in odd-dimensions has massive form fields
satisfying a self-duality condition . We construct such theories
in D=3,5,7.Comment: Latex, 26 pages. References adde
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Differences in code status practice patterns among emergency clinicians working in Japan and the United States
ObjectiveThis study aimed to examine self-reported code-status practice patterns among emergency clinicians from Japan and the U.S.MethodsA cross-sectional questionnaire was distributed to emergency clinicians from one academic medical center and four general hospitals in Japan and two academic medical centers in the U.S. The questionnaire was based on a hypothetical case involving a critically ill patient with end-stage lung cancer. The questionnaire items assessed whether respondent clinicians would be likely to pose questions to patients about their preferences for medical procedures and their values and goals.ResultsA total of 176 emergency clinicians from Japan and the U.S participated. After adjusting for participants' backgrounds, emergency clinicians in Japan were less likely to pose procedure-based questions than those in the U.S. Conversely, emergency clinicians in Japan showed a statistically higher likelihood of asking 10 out of 12 value-based questions.ConclusionSignificant differences were found between emergency clinicians in Japan and the U.S. in their reported practices on posing procedure-based and patient value-based questions.Practice implicationsSerious illness communication training based in the U.S. must be adapted to the Japanese context, considering the cultural characteristics and practical responsibilities of Japanese emergency clinicians
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