1,252 research outputs found
The behavior of fuzzy implications in a fuzzy knowledge base.
More and more companies today discover the advantages of using knowledge bases for their processes and services. Recently, fuzzy set theory has also captured the attention due to good performances within control systems. Therefore, it is very appealing to combine the advantages of these two areas into a fuzzy knowledge base. However, obtaining the results of control systems in a knowleg based environment is not so straightforward. This paper will investigate one aspect of the reasoning process, namely the behavior of the implication. From the different tests performed, four main behaviors of implications can be found. First of all, there are the implications not always resulting in a convex set. A second classs - the so-called impotent implications- doesn't change the predefined set at all. A third grouping reveals always a constant value portion, that rises or falls according to the changed input. A final divsion shifts the complete set in its whole conformably the intuition.Implications; Companies; Advantages; Knowledge; Processes; Theory; Performance; Systems; Value;
Photon temporal modes: a complete framework for quantum information science
Field-orthogonal temporal modes of photonic quantum states provide a new
framework for quantum information science (QIS). They intrinsically span a
high-dimensional Hilbert space and lend themselves to integration into existing
single-mode fiber communication networks. We show that the three main
requirements to construct a valid framework for QIS -- the controlled
generation of resource states, the targeted and highly efficient manipulation
of temporal modes and their efficient detection -- can be fulfilled with
current technology. We suggest implementations of diverse QIS applications
based on this complete set of building blocks.Comment: 17 pages, 13 figure
Variational determination of the second-order density matrix for the isoelectronic series of beryllium, neon and silicon
The isoelectronic series of Be, Ne and Si are investigated using a
variational determination of the second-order density matrix. A semidefinite
program was developed that exploits all rotational and spin symmetries in the
atomic system. We find that the method is capable of describing the strong
static electron correlations due to the incipient degeneracy in the hydrogenic
spectrum for increasing central charge. Apart from the ground-state energy
various other properties are extracted from the variationally determined
second-order density matrix. The ionization energy is constructed using the
extended Koopmans' theorem. The natural occupations are also studied, as well
as the correlated Hartree-Fock-like single particle energies. The exploitation
of symmetry allows to study the basis set dependence and results are presented
for correlation-consistent polarized valence double, triple and quadruple zeta
basis sets.Comment: 19 pages, 7 figures, 3 tables v2: corrected typo in Eq. (52
Kant's philosophy of the aesthetic and the philosophy of praxis
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 Association for Economic and Social Analysis.This essay seeks to reconstruct the terms for a more productive engagement with Kant than is typical within contemporary academic cultural Marxism, which sees him as the cornerstone of a bourgeois model of the aesthetic. The essay argues that, in the Critique of Judgment, the aesthetic stands in as a substitute for the missing realm of human praxis. This argument is developed in relation to Kant's concept of reflective judgment that is in turn related to a methodological shift toward inductive and analogical procedures that help Kant overcome the dualisms of the first two Critiques. This reassessment of Kant's aesthetic is further clarified by comparing it with and offering a critique of Terry Eagleton's assessment of the Kantian aesthetic as synonymous with ideology
Integrated optical Mach-Zehnder interferometer as simazine immunoprobe
Immunoassay has become a versatile tool in several fields of analytical chemistry. We describe the characterization and the application of different integrated optical channel waveguide Mach-Zehnder interferometers (MZIs) as label-free immunoprobes. The performance of the classical MZI is compared with that of a modified structure which incorporates a 3x3 coupler. Characterization of the devices demonstrates a dramatic improvement gained by using the 3x3 coupler. Two main advantages are achieved by the modified device. First, the possibility of referencing the output signal allows the elimination of signal fluctuations due to coupling and light-source instabilities. An increase of the signal-to-noise ratio by a factor of up to 10 is achieved. Secondly, the phase shift between the three outputs allows unambiguous detection with optimum sensitivity. For the detection of the herbicide simazine, the functional properties of the transducer surface are optimized by an appropriate chemical modification. Using this improved device, a simazine immunoassay has been carried out with a test midpoint of 0.3 ppb and a detection limit of approximately 0.1 ppb. The excellent performance, established manufacturing techniques and the potential for simplification and parallelization make the device attractive for further development
A two-way photonic interface for linking Sr+ transition at 422 nm to the telecommunications C-band
We report a single-stage bi-directional interface capable of linking Sr+
trapped ion qubits in a long-distance quantum network. Our interface converts
photons between the Sr+ emission wavelength at 422 nm and the telecoms C-band
to enable low-loss transmission over optical fiber. We have achieved both up-
and down-conversion at the single photon level with efficiencies of 9.4% and
1.1% respectively. Furthermore we demonstrate noise levels that are low enough
to allow for genuine quantum operation in the future.Comment: 5 pages, 4 figure
Theory of noise suppression in {\Lambda}-type quantum memories by means of a cavity
Quantum memories, capable of storing single photons or other quantum states
of light, to be retrieved on-demand, offer a route to large-scale quantum
information processing with light. A promising class of memories is based on
far-off-resonant Raman absorption in ensembles of -type atoms. However
at room temperature these systems exhibit unwanted four-wave mixing, which is
prohibitive for applications at the single-photon level. Here we show how this
noise can be suppressed by placing the storage medium inside a moderate-finesse
optical cavity, thereby removing the main roadblock hindering this approach to
quantum memory.Comment: 10 pages, 3 figures. This paper provides the theoretical background
to our recent experimental demonstration of noise suppression in a
cavity-enhanced Raman-type memory ( arXiv:1510.04625 ). See also the related
paper arXiv:1511.05448, which describes numerical modelling of an atom-filled
cavity. Comments welcom
High-speed noise-free optical quantum memory
Quantum networks promise to revolutionise computing, simulation, and
communication. Light is the ideal information carrier for quantum networks, as
its properties are not degraded by noise in ambient conditions, and it can
support large bandwidths enabling fast operations and a large information
capacity. Quantum memories, devices that store, manipulate, and release on
demand quantum light, have been identified as critical components of photonic
quantum networks, because they facilitate scalability. However, any noise
introduced by the memory can render the device classical by destroying the
quantum character of the light. Here we introduce an intrinsically noise-free
memory protocol based on two-photon off-resonant cascaded absorption (ORCA). We
consequently demonstrate for the first time successful storage of GHz-bandwidth
heralded single photons in a warm atomic vapour with no added noise; confirmed
by the unaltered photon statistics upon recall. Our ORCA memory platform meets
the stringent noise-requirements for quantum memories whilst offering technical
simplicity and high-speed operation, and therefore is immediately applicable to
low-latency quantum networks
Variational two-particle density matrix calculation for the Hubbard model below half filling using spin-adapted lifting conditions
The variational determination of the two-particle density matrix is an
interesting, but not yet fully explored technique that allows to obtain
ground-state properties of a quantum many-body system without reference to an
-particle wave function. The one-dimensional fermionic Hubbard model has
been studied before with this method, using standard two- and three-index
conditions on the density matrix [J. R. Hammond {\it et al.}, Phys. Rev. A 73,
062505 (2006)], while a more recent study explored so-called subsystem
constraints [N. Shenvi {\it et al.}, Phys. Rev. Lett. 105, 213003 (2010)].
These studies reported good results even with only standard two-index
conditions, but have always been limited to the half-filled lattice. In this
Letter we establish the fact that the two-index approach fails for other
fillings. In this case, a subset of three-index conditions is absolutely needed
to describe the correct physics in the strong-repulsion limit. We show that
applying lifting conditions [J.R. Hammond {\it et al.}, Phys. Rev. A 71, 062503
(2005)] is the most economical way to achieve this, while still avoiding the
computationally much heavier three-index conditions. A further extension to
spin-adapted lifting conditions leads to increased accuracy in the intermediate
repulsion regime. At the same time we establish the feasibility of such studies
to the more complicated phase diagram in two-dimensional Hubbard models.Comment: 10 pages, 2 figure
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