1,910 research outputs found
Generalized Landau-Pollak Uncertainty Relation
The Landau-Pollak uncertainty relation treats a pair of rank one projection
valued measures and imposes a restriction on their probability distributions.
It gives a nontrivial bound for summation of their maximum values. We give a
generalization of this bound (weak version of the Landau-Pollak uncertainty
relation). Our generalization covers a pair of positive operator valued
measures. A nontrivial but slightly weak inequality that can treat an arbitrary
number of positive operator valued measures is also presented.Comment: Simplified the proofs. To be published in Phys.Rev.
Hole Transport in p-Type ZnO
A two-band model involving the A- and B-valence bands was adopted to analyze
the temperature dependent Hall effect measured on N-doped \textit{p}-type ZnO.
The hole transport characteristics (mobilities, and effective Hall factor) are
calculated using the ``relaxation time approximation'' as a function of
temperature. It is shown that the lattice scattering by the acoustic
deformation potential is dominant. In the calculation of the scattering rate
for ionized impurity mechanism, the activation energy of 100 or 170 meV is used
at different compensation ratios between donor and acceptor concentrations. The
theoretical Hall mobility at acceptor concentration of
cm is about 70 cmVs with the activation energy of 100 meV
and the compensation ratio of 0.8 at 300 K. We also found that the compensation
ratios conspicuously affected the Hall mobilities.Comment: 5page, 5 figures, accepted for publication in Jpn. J. Appl. Phy
No-Cloning Theorem on Quantum Logics
This paper discusses the no-cloning theorem in a logico-algebraic approach.
In this approach, an orthoalgebra is considered as a general structure for
propositions in a physical theory. We proved that an orthoalgebra admits
cloning operation if and only if it is a Boolean algebra. That is, only
classical theory admits the cloning of states. If unsharp propositions are to
be included in the theory, then a notion of effect algebra is considered. We
proved that an atomic Archimedean effect algebra admitting cloning operation is
a Boolean algebra. This paper also presents a partial result indicating a
relation between cloning on effect algebras and hidden variables.Comment: To appear in J. Math. Phy
Heisenberg's uncertainty principle for simultaneous measurement of positive-operator-valued measures
A limitation on simultaneous measurement of two arbitrary positive operator
valued measures is discussed. In general, simultaneous measurement of two
noncommutative observables is only approximately possible. Following Werner's
formulation, we introduce a distance between observables to quantify an
accuracy of measurement. We derive an inequality that relates the achievable
accuracy with noncommutativity between two observables. As a byproduct a
necessary condition for two positive operator valued measures to be
simultaneously measurable is obtained.Comment: 7 pages, 1 figure. To appear in Phys. Rev.
Roles of the tensor and pairing correlations on the halo formation in 11Li
We study the roles of the tensor and pairing correlations on the halo
formation in 11Li with an extended 9Li+n+n model. We first solve the ground
state of 9Li in the shell model basis by taking 2p-2h states using the Gaussian
functions with variational size parameters to take into account the tensor
correlation fully. In 11Li, the tensor and pairing correlations in 9Li are
Pauli-blocked by additional two neutrons, which work coherently to make the
configurations containing the 0p1/2 state pushed up and close to those
containing the 1s1/2 state. Hence, the pairing interaction works efficiently to
mix the two configurations by equal amount and develop the halo structure in
11Li. For 10Li, the inversion phenomenon of s- and p-states is reproduced in
the same framework. Our model furthermore explains the recently observed
Coulomb breakup strength and charge radius for 11Li.Comment: 8 pages, 5 figure
Information-Disturbance Theorem for Mutually Unbiased Observables
We derive a novel version of information-disturbance theorems for mutually
unbiased observables. We show that the information gain by Eve inevitably makes
the outcomes by Bob in the conjugate basis not only erroneous but random
Steady-State Analysis of Load Balancing with Coxian- Distributed Service Times
This paper studies load balancing for many-server ( servers) systems. Each
server has a buffer of size and can have at most one job in service and
jobs in the buffer. The service time of a job follows the Coxian-2
distribution. We focus on steady-state performance of load balancing policies
in the heavy traffic regime such that the normalized load of system is for We identify a set of policies that
achieve asymptotic zero waiting. The set of policies include several classical
policies such as join-the-shortest-queue (JSQ), join-the-idle-queue (JIQ),
idle-one-first (I1F) and power-of--choices (Po) with . The proof of the main result is based on Stein's method and state space
collapse. A key technical contribution of this paper is the iterative state
space collapse approach that leads to a simple generator approximation when
applying Stein's method
Slow decay of dynamical correlation functions for nonequilibrium quantum states
A property of dynamical correlation functions for nonequilibrium states is
discussed. We consider arbitrary dimensional quantum spin systems with local
interaction and translationally invariant states with nonvanishing current over
them. A correlation function between local charge and local Hamiltonian at
different spacetime points is shown to exhibit slow decay.Comment: typos correcte
Supervised Competitive Learning Part I: SCL with Backpropagation Networks
SCL assembles a set of learning modules into a supervised learning system to address the stability-plasticity dilemma. Each learning module acts as a similarity detector for a prototype, and includes prototype resetting (akin to that of ART) to respond to new prototypes. Here (Part I) we report SCL results using back-propagation networks as the learning modules. We used two feature extractors: about 30 energy-based features, and a combination of energy-based and graphical features (about 60). SCL recognized 98% (energy) and 99% (energy/graphical) of test digits, and 91% (energy) and 96% (energy/graphical) of test letters. In the accompanying paper (Part II), we report the results of SCL using fuzzy sets as learning moduels for recognizing handwritten digits
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