3,341 research outputs found
Local three-nucleon interaction from chiral effective field theory
The three-nucleon (NNN) interaction derived within the chiral effective field
theory at the next-to-next-to-leading order (N2LO) is regulated with a function
depending on the magnitude of the momentum transfer. The regulated NNN
interaction is then local in the coordinate space, which is advantages for some
many-body techniques. Matrix elements of the local chiral NNN interaction are
evaluated in a three-nucleon basis. Using the ab initio no-core shell model
(NCSM) the NNN matrix elements are employed in 3H and 4He bound-state
calculations.Comment: 17 pages, 9 figure
The order of the quantum chromodynamics transition predicted by the standard model of particle physics
We determine the nature of the QCD transition using lattice calculations for
physical quark masses. Susceptibilities are extrapolated to vanishing lattice
spacing for three physical volumes, the smallest and largest of which differ by
a factor of five. This ensures that a true transition should result in a
dramatic increase of the susceptibilities.No such behaviour is observed: our
finite-size scaling analysis shows that the finite-temperature QCD transition
in the hot early Universe was not a real phase transition, but an analytic
crossover (involving a rapid change, as opposed to a jump, as the temperature
varied). As such, it will be difficult to find experimental evidence of this
transition from astronomical observations.Comment: 7 pages, 4 figure
Scattering in Three Flavour ChPT
We present the scattering lengths for the processes in the three
flavour Chiral Perturbation Theory (ChPT) framework at next-to-next-to-leading
order (NNLO). The calculation has been performed analytically but we only
include analytical results for the dependence on the low-energy constants
(LECs) at NNLO due to the size of the expressions. These results, together with
resonance estimates of the NNLO LECs are used to obtain constraints on the
Zweig rule suppressed LECs at NLO, and . Contrary to
expectations from NLO order calculations we find them to be compatible with
zero. We do a preliminary study of combining the results from
scattering, scattering and the scalar form-factors and find only a
marginal compatibility with all experimental/dispersive input data.Comment: 23 page
Stump closure reinforcement with absorbable fibrin collagen sealant sponge (TachoSil®) does not prevent pancreatic fistula after distal pancreatectomy: the FIABLE* multicenter controlled randomized study
International audienceBackground - The aim of this study is to evaluate the effectiveness of TachoSil sponge on distal pancreatectomy remnant stump in reducing the rate and severity of postoperative pancreatic fistula (POPF). Methods - All consecutive patients requiring distal pancreatectomy were randomized in 45 centers. The principal end point was onset of "clinically relevant" POPF. Univariate and multivariate analyses were searched for predictive factors. Results - Of the 270 patients randomized (134 with TachoSil; 136 without), 150 (55.6%) patients sustained a POPF [74 clinically relevant and 76 clinically silent (27.4% and 28.1%), respectively]: no statistically significant difference was found between patients sustaining clinically relevant POPF [41 (30.6%) with vs 33 (24.3%) without TachoSil (P = .276)], or overall POPF [73 (54.5%) with vs 77 (56.6%) without TachoSil, (P = .807)], but there were more clinically relevant POPF after hand-sewn (32.3%) versus mechanical closure (19.8%) (P = .025) and, in case of splenic preservation, after splenic vessel ligation (15/32, 46.9%) versus vascular preservation (17/72, 23.6%) (P = .024). Hand-sewn pancreatic remnant closure (P = .023) and splenic vessel ligation in splenic preservation (P = .035) were independent predictive factors for the onset of clinically relevant POPF. Conclusion - TachoSil sponge reinforcement of the proximal remnant after distal pancreatectomy reduced neither the rate nor the severity of POPF
Brick Walls and AdS/CFT
We discuss the relationship between the bulk-boundary correspondence in
Rehren's algebraic holography (and in other 'fixed-background' approaches to
holography) and in mainstream 'Maldacena AdS/CFT'. Especially, we contrast the
understanding of black-hole entropy from the viewpoint of QFT in curved
spacetime -- in the framework of 't Hooft's 'brick wall' model -- with the
understanding based on Maldacena AdS/CFT. We show that the brick-wall
modification of a Klein Gordon field in the Hartle-Hawking-Israel state on
1+2-Schwarzschild AdS (BTZ) has a well-defined boundary limit with the same
temperature and entropy as the brick-wall-modified bulk theory. One of our main
purposes is to point out a close connection, for general AdS/CFT situations,
between the puzzle raised by Arnsdorf and Smolin regarding the relationship
between Rehren's algebraic holography and mainstream AdS/CFT and the puzzle
embodied in the 'correspondence principle' proposed by Mukohyama and Israel in
their work on the brick-wall approach to black hole entropy. Working on the
assumption that similar results will hold for bulk QFT other than the Klein
Gordon field and for Schwarzschild AdS in other dimensions, and recalling the
first author's proposed resolution to the Mukohyama-Israel puzzle based on his
'matter-gravity entanglement hypothesis', we argue that, in Maldacena AdS/CFT,
the algebra of the boundary CFT is isomorphic only to a proper subalgebra of
the bulk algebra, albeit (at non-zero temperature) the (GNS) Hilbert spaces of
bulk and boundary theories are still the 'same' -- the total bulk state being
pure, while the boundary state is mixed (thermal). We also argue from the
finiteness of its boundary (and hence, on our assumptions, also bulk) entropy
at finite temperature, that the Rehren dual of the Maldacena boundary CFT
cannot itself be a QFT and must, instead, presumably be something like a string
theory.Comment: 54 pages, 3 figures. Arguments strengthened in the light of B.S. Kay
`Instability of Enclosed Horizons' arXiv:1310.739
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