11,568 research outputs found
Real-time Information, Uncertainty and Quantum Feedback Control
Feedback is the core concept in cybernetics and its effective use has made
great success in but not limited to the fields of engineering, biology, and
computer science. When feedback is used to quantum systems, two major types of
feedback control protocols including coherent feedback control (CFC) and
measurement-based feedback control (MFC) have been developed. In this paper, we
compare the two types of quantum feedback control protocols by focusing on the
real-time information used in the feedback loop and the capability in dealing
with parameter uncertainty. An equivalent relationship is established between
quantum CFC and non-selective quantum MFC in the form of operator-sum
representation. Using several examples of quantum feedback control, we show
that quantum MFC can theoretically achieve better performance than quantum CFC
in stabilizing a quantum state and dealing with Hamiltonian parameter
uncertainty. The results enrich understanding of the relative advantages
between quantum MFC and quantum CFC, and can provide useful information in
choosing suitable feedback protocols for quantum systems.Comment: 24 page
Robust manipulation of superconducting qubits in the presence of fluctuations
Superconducting quantum systems are promising candidates for quantum
information processing due to their scalability and design flexibility.
However, the existence of defects, fluctuations, and inaccuracies is
unavoidable for practical superconducting quantum circuits. In this paper, a
sampling-based learning control (SLC) method is used to guide the design of
control fields for manipulating superconducting quantum systems. Numerical
results for one-qubit systems and coupled two-qubit systems show that the
"smart" fields learned using the SLC method can achieve robust manipulation of
superconducting qubits, even in the presence of large fluctuations and
inaccuracies.Comment: 10 pages, 6 figure
Regge-like relation and a universal description of heavy-light systems
Using the Regge-like formula between hadron mass
and angular momentum with a heavy quark mass and a string tension
, we analyze all the heavy-light systems, i.e., mesons
and charmed and bottom baryons.Numerical plots are obtained for all the
heavy-light mesons of experimental data whose slope becomes nearly equal to 1/2
of that for light hadrons. Assuming that charmed and bottom baryons consist of
one heavy quark and one light cluster of two light quarks (diquark), we apply
the formula to all the heavy-light baryons including recently discovered
's and find that these baryons experimentally measured satisfy the
above formula. We predict the average mass values of , , ,
, , and with as 6.01, 6.13, 6.15, 3.05, 3.07,
and 3.34 GeV, respectively. Our results on baryons suggest that these baryons
can be safely regarded as heavy quark-light cluster configuration. We also find
a universal description for all the heavy-light mesons as well as baryons,
i.e., one unique line is enough to describe both of charmed and bottom
heavy-light systems. Our results suggest that instead of mass itself, gluon
flux energy is essential to obtain a linear trajectory.Comment: 10 pages, 8 figures, 5 table
MEGA: An Energy Aware Algorithm for Self-Powered Wireless Sensor Networks in Sustainable Smart Infrastructure
Smart infrastructure is attractive for possessing many desirable features, such as uninterrupted monitoring of health conditions, timely response to damages, and human-infrastructure interactions. Embedded sensors that collectinformation are critical for decision making. However, the lifetime of electronic sensors is a constraint to infrastructure lifetime if sensors are physically embedded in the infrastructure at construction time. In this paper, we studied a self-powered wireless sensor network that harvests energy from mechan-ical vibration in the environment. A dynamic, hierarchical algorithm called MEGA is proposed that constructs clusters and elects the cluster head based on residue energy and energy harvest rate. Taking a smart bridge as an application example, the simulation study has verified the effectiveness of the proposed protocol
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