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Chapman University

2004

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Articles 1 - 18 of 18

Full-Text Articles in Physical Sciences and Mathematics

Exploring The Optimal Sensitivity Of Sum-Variance Nonseparability Criteria For Spin-1/2 Systems, Irfan Ali Khan, John C. Howell Dec 2004

Exploring The Optimal Sensitivity Of Sum-Variance Nonseparability Criteria For Spin-1/2 Systems, Irfan Ali Khan, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

We report on experimental and theoretical studies on recently introduced entanglement measures which use a sum of spin-variance criteria for two spin-1∕2 particles. Three inequalities are explored which exhibit useful concatenating properties. They are each shown to have greater sensitivities than a Bell’s measurement, while each requiring fewer measurements than a Bell’s measurement to obtain. The simplest inequality, requiring just four measurements, is shown to be efficient at testing for entanglement in down-conversion sources which naturally exhibit maximally polarized noise. The most complex inequality, requiring just 12 measurements, is shown to have a sensitivity equal to that of the Peres …

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The Characterization Of Nanosized Nickel-Zinc Ferrites Synthesized Within Reverse Micelles Of Ctab/1-Hexanol/Water Microemulsion, Vuk Uskoković, Miha Drofenik, Irena Ban Dec 2004

The Characterization Of Nanosized Nickel-Zinc Ferrites Synthesized Within Reverse Micelles Of Ctab/1-Hexanol/Water Microemulsion, Vuk Uskoković, Miha Drofenik, Irena Ban

Pharmacy Faculty Articles and Research

Stoichiometric nanocrystalline nickel–zinc ferrites were synthesized by a reverse micelle method following a multi-microemulsion approach. Different pH values were chosen for the alkali precipitating reaction during the synthesis of different powders. Synthesized, as-dried and subsequently calcined powders were characterized in terms of their magnetic properties. XRD analyses and specific-surface area measurements were used to determine the average particle sizes of the synthesized samples. DCS and TGA measurements were performed to reveal the phase transitions within the samples at elevated temperatures, whereas TEM was used to view and record the microstructure of the nanosized ferrite samples. A possible mechanism of the …

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Bell’S Inequalities For Particles Of Arbitrary Spin In Fixed Analyzers, Ronen Mukamel, John C. Howell Nov 2004

Bell’S Inequalities For Particles Of Arbitrary Spin In Fixed Analyzers, Ronen Mukamel, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

We propose a new set of observables for experiments on entangled particles of arbitrarily large spin that produce significant Clauser-Horne-Shimony-Holt inequality violations for fixed analyzer settings over a wider range of spins than was previously possible. These observables are better suited for experiments where analyzer orientations must be chosen before the spin of the entangled particles is known, such as experiments using polarization entangled downconverted photons.

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Application Of Microgels For Optical Tagging, J. Michael Carthcart, L. Andrew Lyon, Marcus Weck, Robert D. Bock Sep 2004

Application Of Microgels For Optical Tagging, J. Michael Carthcart, L. Andrew Lyon, Marcus Weck, Robert D. Bock

Biology, Chemistry, and Environmental Sciences Faculty Books and Book Chapters

In this paper we present results from our research into the use of microgel-based photonic crystals in an optical tagging application. The basis for this research is the phenomena of self-assembly of hydrogel nano- and microparticles (i.e., microgels) into colloidal crystal Bragg reflectors. Previous research has demonstrated the assembly of Bragg structures that are sensitive in the visible spectral region. This current research focuses on the extension of this process into the infrared regime and the use of these infrared-sensitive structures in the creation of an optical tag. In particular, the research effort emphasizes two primary areas: the development of …

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Qvd Sensors As Focal Plane Instruments For X-Ray Timing Applications, Kent S. Wood, Armen Gulian, Paul S. Ray Jul 2004

Qvd Sensors As Focal Plane Instruments For X-Ray Timing Applications, Kent S. Wood, Armen Gulian, Paul S. Ray

Mathematics, Physics, and Computer Science Faculty Articles and Research

“QVD” detectors are based on thermoelectric heat‐to‐voltage (Q→V) conversion and digital (V→D) readout. For spectroscopic applications, the theoretical performance limits are competitive with superconducting tunnel junction (STJ) detectors and transition edge sensor (TES) devices. We discuss theoretical and demonstrated timing performance of QVD detectors with different design architectures. Detectors with lanthanum‐cerium hexaboride sensors can be very fast, up to 100 MHz/pixel counting rates. They can serve as focal plane detectors for X‐ray timing, in situations where very large apertures are used to gather X‐ray photons at high event rates. Practical implementation of thermoelectric (QVD) detectors requires cryogenic thermoelectric sensors with …

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Hong-Ou-Mandel Cloning: Quantum Copying Without An Ancilla, Irfan Ali Khan, John C. Howell Jul 2004

Hong-Ou-Mandel Cloning: Quantum Copying Without An Ancilla, Irfan Ali Khan, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this paper we report an experimental realization of an ancilla-free 1→2 phase-covariant quantum cloner. The cloner is realized by interfering a linearly polarized photon, which we wish to clone with a circularly polarized photon at a beam splitter. The two-photon effect can be understood in light of Hong-Ou-Mandel interference. The fidelity of the cloner was measured as 0.829±0.008 for the 0∕90 basis and 0.835±0.006 for the 45∕135 basis, which is in good agreement with the theoretical prediction of 5∕6 fidelity. The experimental scheme is straightforward and has a high cloning success rate.

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Realization Of The Einstein-Podolsky-Rosen Paradox Using Momentum- And Position-Entangled Photons From Spontaneous Parametric Down Conversion, John C. Howell, Ryan S. Bennink, Sean J. Bentley, Robert W. Boyd May 2004

Realization Of The Einstein-Podolsky-Rosen Paradox Using Momentum- And Position-Entangled Photons From Spontaneous Parametric Down Conversion, John C. Howell, Ryan S. Bennink, Sean J. Bentley, Robert W. Boyd

Mathematics, Physics, and Computer Science Faculty Articles and Research

We report on a momentum-position realization of the EPR paradox using direct detection in the near and far fields of the photons emitted by collinear type-II phase-matched parametric down conversion. Using this approach we achieved a measured two-photon momentum-position variance product of 0.01ℏ2, which dramatically violates the bounds for the EPR and separability criteria.

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Synthesis Of Nanocrystalline Nickel-Zinc Ferrites Via A Microemulsion Route, Vuk Uskoković, Miha Drofenik May 2004

Synthesis Of Nanocrystalline Nickel-Zinc Ferrites Via A Microemulsion Route, Vuk Uskoković, Miha Drofenik

Pharmacy Faculty Articles and Research

Nanostructured NiZn-ferrites were synthesized using a low-temperature co-precipitation method within the reverse micelles of ternary CTAB/1-hexanol/water microemulsions. The influence of pH on the precipitation reaction was investigated. It was found that a higher pH resulted in more crystalline particles. Subsequent oxidation of the ferrous ions precipitate, which leads to the formation of spinel ferrites, is discussed. Diffraction-lines broadening and specific surface area measurements yielded an average particle size of ~ 3 nm. The saturation magnetization of the samples was 20 times smaller than for traditionally synthesized NiZn-ferrites, while the coercivities were 10 - 100 times larger than bulk NiZn-ferrites, which …

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Quantum And Classical Coincidence Imaging, Ryan S. Bennink, Sean J. Bentley, Robert W. Boyd, John C. Howell Jan 2004

Quantum And Classical Coincidence Imaging, Ryan S. Bennink, Sean J. Bentley, Robert W. Boyd, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

Coincidence, or ghost, imaging is a technique that uses two correlated optical fields to form an image of an object. In this work we identify aspects of coincidence imaging which can be performed with classically correlated light sources and aspects which require quantum entanglement. We find that entangled photons allow high-contrast, high-resolution imaging to be performed at any distance from the light source. We demonstrate this fact by forming ghost images in the near and far fields of an entangled photon source, noting that the product of the resolutions of these images is a factor of 3 better than that …

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Methyl Bromide In Preindustrial Air: Measurements From An Antarctic Ice Core, Eric S. Saltzman, Murat Aydin, Warren J. De Bruyn, Daniel B. King, Shari A. Yvon-Lewis Jan 2004

Methyl Bromide In Preindustrial Air: Measurements From An Antarctic Ice Core, Eric S. Saltzman, Murat Aydin, Warren J. De Bruyn, Daniel B. King, Shari A. Yvon-Lewis

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

This paper presents the first ice core measurements of methyl bromide (CH3Br). Samples from a shallow Antarctic ice core (Siple Dome, West Antarctica), ranging in mean gas dates from 1671 to 1942, had a mean CH3Br mixing ratio of 5.8 ppt. These results extend the existing historical record derived from air and Antarctic firn air to about 350 years before present. Model simulations illustrate that the ice core results are consistent with estimates of the impact of anthropogenic activity ( fumigation, combustion, and biomass burning) on the atmospheric CH3Br burden, given the large current uncertainties in the modern atmospheric CH3Br …

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Atmospheric Variability Of Methyl Chloride During The Last 300 Years From An Antarctic Ice Core And Firn Air, M. Aydin, Eric S. Saltzman, Warren J. De Bruyn, S. A. Montzka, J. H. Butler, M. Battle Jan 2004

Atmospheric Variability Of Methyl Chloride During The Last 300 Years From An Antarctic Ice Core And Firn Air, M. Aydin, Eric S. Saltzman, Warren J. De Bruyn, S. A. Montzka, J. H. Butler, M. Battle

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Measurements of methyl chloride (CH3Cl) in Antarctic polar ice and firn air are used to describe the variability of atmospheric CH3Cl during the past 300 years. Firn air results from South Pole and Siple Dome suggest that the atmospheric abundance of CH3Cl increased by about 10% in the 50 years prior to 1990. Ice core measurements from Siple Dome provide evidence for a cyclic natural variability on the order of 10%, with a period of about 110 years in phase with the 20th century rise inferred from firn air. Thus, the CH3Cl increase measured in firn air may largely be …

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Correlation Between Atmospheric Co2 Concentration And Vegetation Greenness In North America: Co2 Fertilization Effect, C. Lim, Menas Kafatos, P. Megonigal Jan 2004

Correlation Between Atmospheric Co2 Concentration And Vegetation Greenness In North America: Co2 Fertilization Effect, C. Lim, Menas Kafatos, P. Megonigal

Mathematics, Physics, and Computer Science Faculty Articles and Research

The possibility that rising atmospheric CO2 concentrations are influencing plant growth in contemporary ecosystems has received little attention, and the studies that exist have been done on a small spatial scale. We correlated the monthly rate of relative change in normalized differenced vegetation index (NDVI) from advanced very high resolution radiometer (AVHRR) data to the rate of change in atmospheric CO2 concentration during the natural vegetation growing season for evidence of a possible CO2 fertilization effect on vegetation development. The study addressed seasonal and annual patterns in spatially averaged NDVI for 3 different ecological regions in North America from 1982 …

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Anomaly-Free Component Adaptation With Class Overriding, Atanas Radenski Jan 2004

Anomaly-Free Component Adaptation With Class Overriding, Atanas Radenski

Mathematics, Physics, and Computer Science Faculty Articles and Research

Software components can be implemented and distributed as collections of classes, then adapted to the needs of specific applications by means of subclassing. Unfortunately, subclassing in collections of related classes may require re-implementation of otherwise valid classes just because they utilize outdated parent classes, a phenomenon that is referred to as the subclassing anomaly. The subclassing anomaly is a serious problem since it can void the benefits of component-based programming altogether. We propose a code adaptation language mechanism called class overriding that is intended to overcome the subclassing anomaly. Class overriding does not create new and isolated derived classes as …

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Measuring Polynomial Invariants Of Multiparty Quantum States, Matthew S. Leifer, N. Linden, A. Winter Jan 2004

Measuring Polynomial Invariants Of Multiparty Quantum States, Matthew S. Leifer, N. Linden, A. Winter

Mathematics, Physics, and Computer Science Faculty Articles and Research

We present networks for directly estimating the polynomial invariants of multiparty quantum states under local transformations. The structure of these networks is closely related to the structure of the invariants themselves and this lends a physical interpretation to these otherwise abstract mathematical quantities. Specifically, our networks estimate the invariants under local unitary (LU) transformations and under stochastic local operations and classical communication (SLOCC). Our networks can estimate the LU invariants for multiparty states, where each party can have a Hilbert space of arbitrary dimension and the SLOCC invariants for multiqubit states. We analyze the statistical efficiency of our networks compared …

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Logical Pre- And Post-Selection Paradoxes, Measurement-Disturbance And Contextuality, Matthew S. Leifer, R. W. Spekkens Jan 2004

Logical Pre- And Post-Selection Paradoxes, Measurement-Disturbance And Contextuality, Matthew S. Leifer, R. W. Spekkens

Mathematics, Physics, and Computer Science Faculty Articles and Research

Many seemingly paradoxical effects are known in the predictions for outcomes of measurements made on pre- and post-selected quantum systems. A class of such effects, which we call “logical pre- and post-selection paradoxes”, bear a striking resemblance to proofs of the Bell-Kochen-Specker theorem, which suggests that they demonstrate the contextuality of quantum mechanics. Despite the apparent similarity, we show that such effects can occur in noncontextual hidden variable theories, provided measurements are allowed to disturb the values of the hidden variables.

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Algebraic Semantics For Coalgebraic Logics, Clemens Kupke, Alexander Kurz, Dirk Pattinson Jan 2004

Algebraic Semantics For Coalgebraic Logics, Clemens Kupke, Alexander Kurz, Dirk Pattinson

Engineering Faculty Articles and Research

With coalgebras usually being defined in terms of an endofunctor T on sets, this paper shows that modal logics for T-coalgebras can be naturally described as functors L on boolean algebras. Building on this idea, we study soundness, completeness and expressiveness of coalgebraic logics from the perspective of duality theory. That is, given a logic L for coalgebras of an endofunctor T, we construct an endofunctor L such that L-algebras provide a sound and complete (algebraic) semantics of the logic. We show that if L is dual to T, then soundness and completeness of the algebraic semantics immediately yield the …

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Coalgebras And Modal Expansions Of Logics, Alexander Kurz, Alessandra Palmigiano Jan 2004

Coalgebras And Modal Expansions Of Logics, Alexander Kurz, Alessandra Palmigiano

Engineering Faculty Articles and Research

In this paper we construct a setting in which the question of when a logic supports a classical modal expansion can be made precise. Given a fully selfextensional logic S, we find sufficient conditions under which the Vietoris endofunctor V on S-referential algebras can be defined and we propose to define the modal expansions of S as the logic that arises from the V-coalgebras. As an example, we also show how the Vietoris endofunctor on referential algebras extends the Vietoris endofunctor on Stone spaces. From another point of view, we examine when a category of ‘spaces’ (X,A), ie sets X …

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Preface, Thomas Hildebrandt, Alexander Kurz Jan 2004

Preface, Thomas Hildebrandt, Alexander Kurz

Engineering Faculty Articles and Research

No abstract provided.

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