Approximate high energy alpha-particle nucleus collision model

Alpha particle-nucleus collision model for nucleon energy and angular distribution prediction and residual nuclei cross section

Hall coefficient of tantalum carbide as function of carbon content

Hall coefficient of tantalum carbide as function of carbon conten

Primary and secondary particle contributions to the depth dose distribution in a phantom shielded from solar flare and Van Allen protons

Calculations have been made using the nucleon-meson transport code NMTC to estimate the absorbed dose and dose equivalent distributions in astronauts inside space vehicles bombarded by solar flare and Van Allen protons. A spherical shell shield of specific radius and thickness with a 30-cm-diam. tissue ball at the geometric center was used to simulate the spacecraft-astronaut configuration. The absorbed dose and the dose equivalent from primary protons, secondary protons, heavy nuclei, charged pions, muons, photons, and positrons and electrons are given as a function of depth in the tissue phantom. Results are given for solar flare protons with a characteristic rigidity of 100 MV and for Van Allen protons in a 240-nautical-mile circular orbit at 30 degree inclination angle incident on both 20-g/sq cm-thick aluminum and polyethylene spherical shell shields

The jet-ISM interaction in the Outer Filament of Centaurus A

The interaction between the radio plasma ejected by the active nucleus of a galaxy and the surrounding medium is a key process that can have a strong impact on the interstellar medium of the galaxy and hence on galaxy evolution. The closest laboratory where we can observe and investigate this phenomenon is the radio galaxy Centaurus A. About 15 kpc north-east of this galaxy, a particularly complex region is found: the so-called Outer Filament where jet-cloud interactions have been proposed to occur. We investigate the presence of signatures of jet-ISM interaction by a detailed study of the kinematics of the ionized gas, expanding on previous results obtained from the HI. We observed two regions of the outer filament with VLT/VIMOS in the IFU observing mode. Emission from Hbeta and [OIII]4959,5007\AA\ is detected in both pointings. We found two distinct kinematical components of ionized gas that well match the kinematics of the nearby HI cloud. One component follows the regular kinematics of the rotating gas while the second shows similar velocities to those of the nearby HI component thought to be disturbed by an interaction with the radio jet. We suggest that the ionized and atomic gas are part of the same dynamical gas structure originating as result of the merger that shaped Centaurus A and which is regularly rotating around Centaurus A as proposed by other authors. The gas (ionized and HI) with anomalous velocities is tracing the interaction of the Large-Scale radio Jet with the ISM, suggesting that, although poorly collimated as structure, the jet is still active. However, we can exclude that a strong shock is driving the ionization of the gas. It is likely that a combination of jet entrainment and photoionization by the UV continuum from the central engine is needed in order to explain both the ionization and the kinematics of the gas in the Outer Filament.Comment: 6 pages, 6 figures, 1 table. Final version accepted for publication on A&

Absolute Efficiency Measurements of NE-213 ORGANIC Phosphors for Detecting 14.4 and 2.6 Mev Neutrons

Efficiency measurements of organic phosphor scintillator for detecting 14.4 and 2.6 MeV neutron

The outer filament of Centaurus A as seen by MUSE

We investigate signatures of a jet-interstellar medium (ISM) interaction using optical integral-field observations of the so-called outer filament near Centaurus A, expanding on previous results obtained on a more limited area. Using the Multi Unit Spectroscopic Explorer (MUSE) on the VLT during science verification, we observed a significant fraction of the brighter emitting gas across the outer filament. The ionized gas shows complex morphology with compact blobs, arc-like structures and diffuse emission. Based on the kinematics, we identified three main components. The more collimated component is oriented along the direction of the radio jet. The other two components exhibit diffuse morphology together with arc-like structures also oriented along the radio jet direction. Furthermore, the ionization level of the gas is found to decrease from the more collimated component to the more diffuse components. The morphology and velocities of the more collimated component confirm our earlier results that the outer filament and the nearby HI cloud are likely partially shaped by the lateral expansion of the jet. The arc-like structures embedded within the two remaining components are the clearest evidence of a smooth jet-ISM interaction along the jet direction. This suggests that, although poorly collimated, the radio jet is still active and has an impact on the surrounding gas. This result indicates that the effect on the ISM of even low-power radio jets should be considered when studying the influence Active Galactic Nuclei can have on their host galaxy.Comment: 5 pages, 3 figures, Accepted for publication by A&

Convergence of Quantum Annealing with Real-Time Schrodinger Dynamics

Convergence conditions for quantum annealing are derived for optimization problems represented by the Ising model of a general form. Quantum fluctuations are introduced as a transverse field and/or transverse ferromagnetic interactions, and the time evolution follows the real-time Schrodinger equation. It is shown that the system stays arbitrarily close to the instantaneous ground state, finally reaching the target optimal state, if the strength of quantum fluctuations decreases sufficiently slowly, in particular inversely proportionally to the power of time in the asymptotic region. This is the same condition as the other implementations of quantum annealing, quantum Monte Carlo and Green's function Monte Carlo simulations, in spite of the essential difference in the type of dynamics. The method of analysis is an application of the adiabatic theorem in conjunction with an estimate of a lower bound of the energy gap based on the recently proposed idea of Somma et. al. for the analysis of classical simulated annealing using a classical-quantum correspondence.Comment: 6 pages, minor correction

Quantum baker maps with controlled-NOT coupling

The characteristic stretching and squeezing of chaotic motion is linearized within the finite number of phase space domains which subdivide a classical baker map. Tensor products of such maps are also chaotic, but a more interesting generalized baker map arises if the stacking orders for the factor maps are allowed to interact. These maps are readily quantized, in such a way that the stacking interaction is entirely attributed to primary qubits in each map, if each subsystem has power-of-two Hilbert space dimension. We here study the particular example of two baker maps that interact via a controlled-not interaction. Numerical evidence indicates that the control subspace becomes an ideal Markovian environment for the target map in the limit of large Hilbert space dimension.Comment: 8 page