13,386 research outputs found
Resolving Gas Flows in the Ultraluminous Starburst IRAS23365+3604 with Keck LGSAO/OSIRIS
Keck OSIRIS/LGSAO observations of the ultraluminous galaxy IRAS~23365+3604
resolve a circumnuclear bar (or irregular disk) of semimajor axis 0.42" (520
pc) in Paschen-alpha emission. The line-of-sight velocity of the ionized gas
increases from the northeast toward the southwest; this gradient is
perpendicular to the photometric major axis of the infrared emission. Two pairs
of bends in the zero-velocity line are detected. The inner bend provides
evidence for gas inflow onto the circumnuclear disk/bar structure. We interpret
the gas kinematics on kiloparsec scales in relation to the molecular gas disk
and multiphase outflow discovered previously. In particular, the fast component
of the outflow (detected previously in line wings) is not detected, adding
support to the conjecture that the fast wind originates well beyond the
nucleus. These data directly show the dynamics of gas inflow and outflow in the
central kiloparsec of a late-stage, gas-rich merger and demonstrate the
potential of integral field spectroscopy to improve our understanding of the
role of gas flows during the growth phase of bulges and supermassive black
holes.Comment: 14 pages with 7 figures accepted to the astrophysical journa
Practical implementation of mutually unbiased bases using quantum circuits
The number of measurements necessary to perform the quantum state
reconstruction of a system of qubits grows exponentially with the number of
constituents, creating a major obstacle for the design of scalable tomographic
schemes. We work out a simple and efficient method based on cyclic generation
of mutually unbiased bases. The basic generator requires only Hadamard and
controlled-phase gates, which are available in most practical realizations of
these systems. We show how complete sets of mutually unbiased bases with
different entanglement structures can be realized for three and four qubits. We
also analyze the quantum circuits implementing the various entanglement
classes.Comment: 5 pages, 2 color figures. Comments welcome
A sum rule for charged elementary particles
There may be a link between the quantum properties of the vacuum and the
parameters describing the properties of light propagation, culminating in a sum
over all types of elementary particles existing in Nature weighted only by
their squared charges and independent of their masses. The estimate for that
sum is of the order of 100.Comment: Accepted for publication in European Physical Journal
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