58,561 research outputs found
Quantum parallelism of the controlled-NOT operation: an experimental criterion for the evaluation of device performance
It is shown that a quantum controlled-NOT gate simultaneously performs the
logical functions of three distinct conditional local operations. Each of these
local operations can be verified by measuring a corresponding truth table of
four local inputs and four local outputs. The quantum parallelism of the gate
can then be observed directly in a set of three simple experimental tests, each
of which has a clear intuitive interpretation in terms of classical logical
operations. Specifically, quantum parallelism is achieved if the average
fidelity of the three classical operations exceeds 2/3. It is thus possible to
evaluate the essential quantum parallelism of an experimental controlled-NOT
gate by testing only three characteristic classical operations performed by the
gate.Comment: 6 pages, no figures, added references and discussio
(2317) meson production at RHIC
Production of (2317) mesons in relativistic heavy ion collisions at
RHIC is studied. Using the quark coalescence model, we first determine the
initial number of (2317) mesons produced during hadronization of
created quark-gluon plasma. The predicted (2317) abundance depends
sensitively on the quark structure of the (2317) meson. An
order-of-magnitude larger yield is obtained for a conventional two-quark than
for an exotic four-quark (2317) meson. To include the hadronic effect
on the (2317) meson yield, we have evaluated the absorption cross
sections of the (2317) meson by pion, rho, anti-kaon, and vector
anti-kaon in a phenomenological hadronic model. Taking into consideration the
absorption and production of (2317) mesons during the hadronic stage of
heavy ion collisions via a kinetic model, we find that the final yield of
(2317) mesons remains sensitive to its initial number produced from the
quark-gluon plasma, providing thus the possibility of studying the quark
structure of the (2317) meson and its production mechanism in
relativistic heavy ion collisions.Comment: 12 pages, 6 figure
Gravitational Lorentz anomaly from the overlap formula in 2-dimensions
In this letter we show that the overlap formulation of chiral gauge theories
correctly reproduces the gravitational Lorentz anomaly in 2-dimensions. This
formulation has been recently suggested as a solution to the fermion doubling
problem on the lattice. The well known response to general coordinate
transformations of the effective action of Weyl fermions coupled to gravity in
2-dimensions can also be recovered.Comment: 7 pages, late
Phase Transition Couplings in the Higgsed Monopole Model
Using a one-loop approximation for the effective potential in the Higgs model
of electrodynamics for a charged scalar field, we argue for the existence of a
triple point for the renormalized (running) values of the selfinteraction
and the "charge" g given by . Considering the
beta-function as a typical quantity we estimate that the one-loop approximation
is valid with accuracy of deviations not more than 30% in the region of the
parameters: The phase diagram given in the present paper
corresponds to the above-mentioned region of . Under the
point of view that the Higgs particle is a monopole with a magnetic charge g,
the obtained electric fine structure constant turns out to be
by the Dirac relation. This value is very close
to the which in a U(1) lattice gauge theory
corresponds to the phase transition between the "Coulomb" and confinement
phases. Such a result is very encouraging for the idea of an approximate
"universality" (regularization independence) of gauge couplings at the phase
transition point. This idea was suggested by the authors in their earlier
papers.Comment: 27 pages, 3 figure
Characterizing Behavioural Congruences for Petri Nets
We exploit a notion of interface for Petri nets in order to design a set of net combinators. For such a calculus of nets, we focus on the behavioural congruences arising from four simple notions of behaviour, viz., traces, maximal traces, step, and maximal step traces, and from the corresponding four notions of bisimulation, viz., weak and weak step bisimulation and their maximal versions. We characterize such congruences via universal contexts and via games, providing in such a way an understanding of their discerning powers
A hermeneutic inquiry into user-created personas in different Namibian locales
Persona is a tool broadly used in technology design to support communicational interactions between designers and users. Different Persona types and methods have evolved mostly in the Global North, and been partially deployed in the Global South every so often in its original User-Centred Design methodology. We postulate persona conceptualizations are expected to differ across cultures. We demonstrate this with an exploratory-case study on user-created persona co-designed with four Namibian ethnic groups: ovaHerero, Ovambo, ovaHimba and Khoisan. We follow a hermeneutic inquiry approach to discern cultural nuances from diverse human conducts. Findings reveal diverse self-representations whereby for each ethnic group results emerge in unalike fashions, viewpoints, recounts and storylines. This paper ultimately argues User-Created Persona as a potentially valid approach for pursuing cross-cultural depictions of personas that communicate cultural features and user experiences paramount to designing acceptable and gratifying technologies in dissimilar locales
Dynamical Entanglement in Particle Scattering
This paper explores the connections between particle scattering and quantum
information theory in the context of the non-relativistic, elastic scattering
of two spin-1/2 particles. An untangled, pure, two-particle in-state is evolved
by an S-matrix that respects certain symmetries and the entanglement of the
pure out-state is measured. The analysis is phrased in terms of unitary,
irreducible representations (UIRs) of the symmetry group in question, either
the rotation group for the spin degrees of freedom or the Galilean group for
non-relativistic particles. Entanglement may occurs when multiple UIRs appear
in the direct sum decomposition of the direct product in-state, but it also
depends of the scattering phase shifts. \keywords{dynamical entanglement,
scattering, Clebsch-Gordan methods}Comment: 6 pages, submitted to Int. J. Mod. Phys. A as part of MRST 2005
conference proceeding
Entanglement Sudden Death as an Indicator of Fidelity in a Four-Qubit Cluster State
I explore the entanglement evolution of a four qubit cluster state in a
dephasing environment concentrating on the phenomenon of entanglement sudden
death (ESD). Specifically, I ask whether the onset of ESD has an effect on the
utilization of this cluster state as a means of implementing a single qubit
rotation in the measurement based cluster state model of quantum computation.
To do this I compare the evolution of the entanglement to the fidelity, a
measure of how accurately the desired state (after the measurement based
operations) is achieved. I find that ESD does not cause a change of behavior or
discontinuity in the fidelity but may indicate when the fidelity of certain
states goes to .5.Comment: 8 pages, 9 figure
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