68,534 research outputs found
Spin Hydrodynamic Generation in the Charged Subatomic Swirl
Recently there have been significant interests in the spin hydrodynamic
generation phenomenon from multiple disciplines of physics. Such phenomenon
arises from global polarization effect of microscopic spin by macroscopic fluid
rotation and is expected to occur in the hot quark-gluon fluid (the ``subatomic
swirl'') created in relativistic nuclear collisions. This was indeed discovered
in experiments which however revealed an intriguing puzzle: a polarization
difference between particles and anti-particles. We suggest a novel application
of a general connection between rotation and magnetic field: a magnetic field
naturally arises along the fluid vorticity in the charged subatomic swirl. We
establish this mechanism as a new way for generating long-lived in-medium
magnetic field in heavy ion collisions. Due to its novel feature, this new
magnetic field provides a nontrivial explanation to the puzzling observation of
a difference in spin hydrodynamic generation for particles and anti-particles
in heavy ion collisions.Comment: 10 pages, 3 figures, title changed according to published versio
Generation of short hard X-ray pulses of tailored duration using a M\"ossbauer source
We theoretically investigate a scheme for generations of single hard X-ray
pulses of controllable duration in the range of 1 ns - 100 ns from a
radioactive M\"ossbauer source. The scheme uses a magnetically perturbed
FeBO crystal illuminated with recoilless 14.4 keV photons from a
radioisotope Co nuclide. Such compact X-ray source is useful for the
extension of quantum optics to 10 keV energy scale which has been spotlighted
in recent years. So far, experimental achievements are mostly performed in
synchrotron radiation facilities. However, tabletop and portable hard X-ray
sources are still limited for time-resolved measurements and for implementing
coherent controls over nuclear quantum optics systems. The availability of
compact hard X-ray sources may become the engine to apply schemes of quantum
information down to the subatomic scale. We demonstrate that the present method
is versatile and provides an economic solution utilizing a M\"ossbauer source
to perform time-resolved nuclear scattering, to produce suitable pulses for
photon storage and to flexibly generate X-ray single-photon entanglement.Comment: 8 pages, 6 figure
Human-Robot Trust Integrated Task Allocation and Symbolic Motion planning for Heterogeneous Multi-robot Systems
This paper presents a human-robot trust integrated task allocation and motion
planning framework for multi-robot systems (MRS) in performing a set of tasks
concurrently. A set of task specifications in parallel are conjuncted with MRS
to synthesize a task allocation automaton. Each transition of the task
allocation automaton is associated with the total trust value of human in
corresponding robots. Here, the human-robot trust model is constructed with a
dynamic Bayesian network (DBN) by considering individual robot performance,
safety coefficient, human cognitive workload and overall evaluation of task
allocation. Hence, a task allocation path with maximum encoded human-robot
trust can be searched based on the current trust value of each robot in the
task allocation automaton. Symbolic motion planning (SMP) is implemented for
each robot after they obtain the sequence of actions. The task allocation path
can be intermittently updated with this DBN based trust model. The overall
strategy is demonstrated by a simulation with 5 robots and 3 parallel subtask
automata
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