11,680 research outputs found
Hall coefficient of tantalum carbide as function of carbon content
Hall coefficient of tantalum carbide as function of carbon conten
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&
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&
Faster annealing schedules for quantum annealing
New annealing schedules for quantum annealing are proposed based on the
adiabatic theorem. These schedules exhibit faster decrease of the excitation
probability than a linear schedule. To derive this conclusion, the asymptotic
form of the excitation probability for quantum annealing is explicitly obtained
in the limit of long annealing time. Its first-order term, which is inversely
proportional to the square of the annealing time, is shown to be determined
only by the information at the initial and final times. Our annealing schedules
make it possible to drop this term, thus leading to a higher order (smaller)
excitation probability. We verify these results by solving numerically the
time-dependent Schrodinger equation for small size systemsComment: 10 pages, 5 figures, minor correction
Spatially Resolved Species Measurements in a GO2/GH2 Propellant Rocket
The objective of the current work is to develop an non-intrusive technique to experimentally determine the major species and temperature field in the combustion chamber of a uni-element rocket for a GO2/GH2 propellant combination
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
Residual Energies after Slow Quantum Annealing
Features of the residual energy after the quantum annealing are investigated.
The quantum annealing method exploits quantum fluctuations to search the ground
state of classical disordered Hamiltonian. If the quantum fluctuation is
reduced sufficiently slowly and linearly by the time, the residual energy after
the quantum annealing falls as the inverse square of the annealing time. We
show this feature of the residual energy by numerical calculations for
small-sized systems and derive it on the basis of the quantum adiabatic
theorem.Comment: 4 pages, 2 figure
Strong Correlations in Electron Doped Phthalocyanine Conductors Near Half Filling
We propose that electron doped nontransition metal-phthalocyanines (MPc) like
ZnPc and MgPc, similar to those very recently reported, should constitute novel
strongly correlated metals. Due to orbital degeneracy, Jahn-Teller coupling and
Hund's rule exchange, and with a large on-site Coulomb repulsion, these
molecular conductors should display, particularly near half filling at two
electrons/molecule, very unconventional properties, including Mott insulators,
strongly correlated superconductivity, and other intriguing phases.Comment: 4 pages, 1 figure, submited to PR
Convergence theorems for quantum annealing
We prove several theorems to give sufficient conditions for convergence of
quantum annealing, which is a protocol to solve generic optimization problems
by quantum dynamics. In particular the property of strong ergodicity is proved
for the path-integral Monte Carlo implementation of quantum annealing for the
transverse Ising model under a power decay of the transverse field. This result
is to be compared with the much slower inverse-log decay of temperature in the
conventional simulated annealing. Similar results are proved for the Green's
function Monte Carlo approach. Optimization problems in continuous space of
particle configurations are also discussed.Comment: 19 page
- …