11,410 research outputs found
On Nonperturbative Exactness of Konishi Anomaly and the Dijkgraaf-Vafa Conjecture
In this paper we study the nonperturbative corrections to the generalized
Konishi anomaly that come from the strong coupling dynamics of the gauge
theory. We consider U(N) gauge theory with adjoint and Sp(N) or SO(N) gauge
theory with symmetric or antisymmetric tensor. We study the algebra of chiral
rotations of the matter field and show that it does not receive nonperturbative
corrections. The algebra implies Wess-Zumino consistency conditions for the
generalized Konishi anomaly which are used to show that the anomaly does not
receive nonperturbative corrections for superpotentials of degree less than
2l+1 where 2l=3c(Adj)-c(R) is the one-loop beta function coefficient. The
superpotentials of higher degree can be nonperturbatively renormalized because
of the ambiguities in the UV completion of the gauge theory. We discuss the
implications for the Dijkgraaf-Vafa conjecture.Comment: 23 page
Two Wide Planetary-mass Companions to Solar-type Stars in Upper Scorpius
At wide separations, planetary-mass and brown dwarf companions to solar-type stars occupy a curious region of
parameter space not obviously linked to binary star formation or solar system scale planet formation. These
companions provide insight into the extreme case of companion formation (either binary or planetary), and
due to their relative ease of observation when compared to close companions, they offer a useful template
for our expectations of more typical planets. We present the results from an adaptive optics imaging survey
for wide (~50–500 AU) companions to solar-type stars in Upper Scorpius. We report one new discovery of a
~14 M_J companion around GSC 06214−00210and confirm that the candidate planetary-mass companion 1RXS
J160929.1−210524 detected by Lafrenière et al. is in fact comoving with its primary star. In our survey, these
two detections correspond to ~4% of solar-type stars having companions in the 6–20 M_J mass and ~200–500 AU
separation range. This figure is higher than would be expected if brown dwarfs and planetary-mass companions
were drawn from an extrapolation of the binary mass function. Finally, we discuss implications for the formation
of these objects
Application of advanced technologies to small, short-haul transport aircraft (STAT)
The benefits of selected advanced technologies for 19 and 30 passenger, short-haul aircraft were identified. Advanced technologies were investigated in four areas: aerodynamics, propulsion, structures, and ride quality. Configuration sensitivity studies were conducted to show design tradeoffs associated with passenger capacity, cabin comfort level, and design field length
Two Wide Planetary-Mass Companions to Solar-Type Stars in Upper Scorpius
At wide separations, planetary-mass and brown dwarf companions to solar type
stars occupy a curious region of parameters space not obviously linked to
binary star formation or solar-system scale planet formation. These companions
provide insight into the extreme case of companion formation (either binary or
planetary), and due to their relative ease of observation when compared to
close companions, they offer a useful template for our expectations of more
typical planets. We present the results from an adaptive optics imaging survey
for wide (50-500 AU) companions to solar type stars in Upper Scorpius. We
report one new discovery of a ~14 M_J companion around GSC 06214-00210, and
confirm that the candidate planetary mass companion 1RXS J160929.1-210524
detected by Lafreniere et al (2008) is in fact co-moving with its primary star.
In our survey, these two detections correspond to ~4% of solar type stars
having companions in the 6-20 M_J mass and 200-500 AU separation range. This
figure is higher than would be expected if brown dwarfs and planetary mass
companions were drawn from an extrapolation of the binary mass function.
Finally, we discuss implications for the formation of these objects.Comment: 11 Pages, 7 Figures, Accepted for Ap
Predictions of hadron abundances in pp collisions at the LHC
Based on the statistical hadronization model, we obtain quantitative
predictions for the relative abundances of hadron species in pp collisions at
the LHC. By using the parameters of the model determined at sqrt s = 200 GeV,
and extrapolating the overall normalization from ppbar collisions at the SPS
and Tevatron, we find that the expected rapidity densities are almost
grand-canonical. Therefore, at LHC the ratios between different species become
essentially energy-independent, provided that the hadronization temperature T_H
and the strangeness suppression factor gamma_S retain the stable values
observed in the presently explored range of pp and ppbar collisions.Comment: 4 pages. Final version published in JP
Fluid-crystal coexistence for proteins and inorganic nanocolloids: dependence on ionic strength
We investigate theoretically the fluid-crystal coexistence of solutions of
globular charged nanoparticles like proteins and inorganic colloids. The
thermodynamic properties of the fluid phase are computed via the optimized
Baxter model. This is done specifically for lysozyme and silicotungstates for
which the bare adhesion parameters are evaluated via the experimental second
virial coefficients. The electrostatic free energy of the crystal is
approximated by supposing the cavities in the interstitial phase between the
particles are spherical in form. In the salt-free case a Poisson-Boltzmann
equation is solved to calculate the effective charge on a particle and a Donnan
approximation is used to derive the chemical potential and osmotic pressure in
the presence of salt. The coexistence data of lysozyme and silicotungstates are
analyzed within this scheme, especially with regard to the ionic-strength
dependence of the chemical potentials. The latter agree within the two phases
provided some upward adjustment of the effective charge is allowed for.Comment: 15 pages, 9 figure
1/t pressure and fermion behaviour of water in two dimensions
A variety of metal vacuum systems display the celebrated 1/t pressure, namely
power-law dependence on time t, with the exponent close to unity, the origin of
which has been a long-standing controversy. Here we propose a chemisorption
model for water adsorbates, based on the argument for fermion behaviour of
water vapour adsorbed on a stainless-steel surface, and obtain analytically the
power-law behaviour of pressure, with an exponent of unity. Further, the model
predicts that the pressure should depend on the temperature T according to
T^(3/2), which is indeed confirmed by our experiment. Our results should help
elucidate the unique characteristics of the adsorbed water.Comment: 11 pages, 4 figure
Black Rings in Taub-NUT
We construct the most generic three-charge, three-dipole-charge, BPS
black-ring solutions in a Taub-NUT background. These solutions depend on seven
charges and six moduli, and interpolate between a four-dimensional black hole
and a five-dimensional black ring. They are also instrumental in determining
the correct microscopic description of the five-dimensional BPS black rings.Comment: 16 pages, harvma
System thermal-hydraulic modelling of the phénix dissymmetric test benchmark
Phénix is a French pool-type sodium-cooled prototype reactor; before the definitive shutdown, occurred in 2009, a final set of experimental tests are carried out in order to increase the knowledge on the operation and the safety aspect of the pool-type liquid metal-cooled reactors. One of the experiments was the Dissymmetric End-of-Life Test which was selected for the validation benchmark activity in the frame of SESAME project. The computer code validation plays a key role in the safety assessment of the innovative nuclear reactors and the Phénix dissymmetric test provides useful experimental data to verify the computer codes capability in the asymmetric thermal-hydraulic behaviour into a pool-type liquid metal-cooled reactor. This paper shows the comparison of the outcomes obtained with six different System Thermal-Hydraulic (STH) codes: RELAP5-3D©, SPECTRA, ATHLET, SAS4A/SASSYS-1, ASTEC-Na and CATHARE. The nodalization scheme of the reactor was individually achieved by the participants; during the development of the thermal-hydraulic model, the pool nodalization methodology had a special attention in order to investigate the capability of the STH codes to reproduce the dissymmetric effects which occur in each loop and into pools, caused by the azimuthal asymmetry of the boundary conditions. The modelling methodology of the participants is discussed and the main results are compared in this paper to obtain useful guide lines for the future modelling of innovative liquid metal pool-type reactors
Protecting subspaces by acting on the outside
Many quantum control tasks aim at manipulating the state of a quantum
mechanical system within a finite subspace of states. However, couplings to the
outside are often inevitable. Here we discuss strategies which keep the system
in the controlled subspace by applying strong interactions onto the outside.
This is done by drawing analogies to simple toy models and to the quantum Zeno
effect. Special attention is paid to the constructive use of dissipation in the
protection of subspaces.Comment: 16 pages, 10 figure
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