26,283 research outputs found
Left-Right Asymmetry of Weak Interaction Mass of Polarized Fermions in Flight
The left-right polarization-dependent asymmetry of the weak interaction mass
is investigated. Based on the Standard Model, the calculation shows that the
weak interaction mass of left-handed polarized fermions is always greater than
that of right-handed polarized fermions in flight with the same velocity in any
inertial frame. The asymmetry of the weak interaction mass might be very
important to the investigation of neutrino mass and would have an important
significance for understanding the parity nonconservation in weak interactions.Comment: 8 pages, 2 figures, corrected calculatio
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On defining partition entropy by inequalities
Partition entropy is the numerical metric of uncertainty within
a partition of a finite set, while conditional entropy measures the degree of
difficulty in predicting a decision partition when a condition partition is
provided. Since two direct methods exist for defining conditional entropy
based on its partition entropy, the inequality postulates of monotonicity,
which conditional entropy satisfies, are actually additional constraints on
its entropy. Thus, in this paper partition entropy is defined as a function
of probability distribution, satisfying all the inequalities of not only partition
entropy itself but also its conditional counterpart. These inequality
postulates formalize the intuitive understandings of uncertainty contained
in partitions of finite sets.We study the relationships between these inequalities,
and reduce the redundancies among them. According to two different
definitions of conditional entropy from its partition entropy, the convenient
and unified checking conditions for any partition entropy are presented, respectively.
These properties generalize and illuminate the common nature
of all partition entropies
Backaction of a charge detector on a double quantum dot
We develop a master equation approach to study the backaction of quantum
point contact (QPC) on a double quantum dot (DQD) at zero bias voltage. We
reveal why electrons can pass through the zero-bias DQD only when the bias
voltage across the QPC exceeds a threshold value determined by the eigenstate
energy difference of the DQD. This derived excitation condition agrees well
with experiments on QPC-induced inelastic electron tunneling through a DQD [S.
Gustavsson et al., Phys. Rev. Lett. 99, 206804(2007)]. Moreover, we propose a
new scheme to generate a pure spin current by the QPC in the absence of a
charge current.Comment: 6 pages, 4 figure
Learning Points and Routes to Recommend Trajectories
The problem of recommending tours to travellers is an important and broadly
studied area. Suggested solutions include various approaches of
points-of-interest (POI) recommendation and route planning. We consider the
task of recommending a sequence of POIs, that simultaneously uses information
about POIs and routes. Our approach unifies the treatment of various sources of
information by representing them as features in machine learning algorithms,
enabling us to learn from past behaviour. Information about POIs are used to
learn a POI ranking model that accounts for the start and end points of tours.
Data about previous trajectories are used for learning transition patterns
between POIs that enable us to recommend probable routes. In addition, a
probabilistic model is proposed to combine the results of POI ranking and the
POI to POI transitions. We propose a new F score on pairs of POIs that
capture the order of visits. Empirical results show that our approach improves
on recent methods, and demonstrate that combining points and routes enables
better trajectory recommendations
Impact of Topology on Service Availability in a Smart Grid Advanced Metering Infrastructure
over the last decade, Wireless Sensor Networks (WSNs) have brought radical changes to the means and forms of communication for monitoring and control of a large number of applications including Smart Grid (SG). Traditional energy networks have been modernized to Smart Grids to boost the energy industry in the context of efficient and effective power management, performance, real-time control and information flow using two-way communication between utility provides and end-users. However, integrating two-way communication in smart grid comes at the cost of cyber security vulnerabilities and challenges. In the context of SG, node capture is a severe security threat due to the fact that a compromised node can significantly impact the operations and security of the SG network. In this paper, node compromise attack is explored on Advance Metering Infrastructure (AMI) with smart meters for Neighbor Area Networks (NANs) in star and mesh network topologies. Simulation of node compromise/failure for a SG network, using ZigBee nodes in simulation indicates that a partial mesh topology is more resilient to node capture attacks as compared to star topology. A larger number of nodes are reachable from the control center of the SG in a partial mesh topology compared to that in a star topology
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