Modal quantum theory

We present a discrete model theory similar in structure to ordinary quantum mechanics, but based on a finite field instead of complex amplitudes. The interpretation of this theory involves only the "modal" concepts of possibility and necessity rather than quantitative probability measures. Despite its simplicity, our model theory includes entangled states and has versions of both Bell's theorem and the no cloning theorem.Comment: Presented at the 7th Workshop on Quantum Physics and Logic, Oxford University (29-30 May 2010). Revised 1 Aug 2011 in response to referee comment

Building multiparticle states with teleportation

We describe a protocol which can be used to generate any N-partite pure quantum state using Einstein-Podolsky-Rosen (EPR) pairs. This protocol employs only local operations and classical communication between the N parties (N-LOCC). In particular, we rely on quantum data compression and teleportation to create the desired state. This protocol can be used to obtain upper bounds for the bipartite entanglement of formation of an arbitrary N-partite pure state, in the asymptotic limit of many copies. We apply it to a few multipartite states of interest, showing that in some cases it is not optimal. Generalizations of the protocol are developed which are optimal for some of the examples we consider, but which may still be inefficient for arbitrary states.Comment: 11 pages, 1 figure. Version 2 contains an example for which protocol P3 is better than protocol P2. Correction to references in version

Development of a frit 202 analytic standard for the Defense Waste Processing Facility

During the qualification of Frit 202 samples for the `DWPF Cold Runs`, the need for a reliable chemical frit standard became apparent. A standard was prepared by obtaining a quantity of Frit 202 and grinding into a fine powder. This material was homogenized as one slurry material volume, spray dried to prevent segregation, and hydraulically pressed into discs. These discs were fired and packaged into eleven sub-lots containing approximately 2,000 discs per sub-lot. A number of samples were obtained and analyzed by two analytic laboratories. The chemical analyses were carefully reviewed and evaluated by several statistical means. While there were several statistically significant variations between the sub-lots, it is believed that those variations are partially caused by the variability of the analytic method. These discs should provide a reliable standard for future chemical analyses of DWPF Frits similar in comparison to Frit 202. It is recommended that these discs be used as a standard material included with the representative frit sample to the independent chemical analysis laboratory, and the order of use of these standards be from sub-lot eleven to sub-lot four. It is further recommended that the NIST standard material (93a) be employed along with the 202 standard until confidence in the new standard is gained. The NIST standard should also be used when initial use of a new sub-lot is begun. this procedure should continue to the end of the DWPF program or such time as the chemical composition of the frit is extensively modified

No-hidden-variables proof for two spin-1/2 particles preselected and postselected in unentangled states

It is a well-known fact that all the statistical predictions of quantum mechanics on the state of any physical system represented by a two-dimensional Hilbert space can always be duplicated by a noncontextual hidden-variables model. In this paper, I show that, in some cases, when we consider an additional independent (unentangled) two-dimensional system, the quantum description of the resulting composite system cannot be reproduced using noncontextual hidden variables. In particular, a no-hidden-variables proof is presented for two individual spin-1/2 particles preselected in an uncorrelated state AB and postselected in another uncorrelated state aB, B being the same state for the second particle in both preselection and postselection.Comment: LaTeX, 8 page

Notes on entropic characteristics of quantum channels

One of most important issues in quantum information theory concerns transmission of information through noisy quantum channels. We discuss few channel characteristics expressed by means of generalized entropies. Such characteristics can often be dealt in line with more usual treatment based on the von Neumann entropies. For any channel, we show that the $q$-average output entropy of degree $q\geq1$ is bounded from above by the $q$-entropy of the input density matrix. Concavity properties of the $(q,s)$-entropy exchange are considered. Fano type quantum bounds on the $(q,s)$-entropy exchange are derived. We also give upper bounds on the map $(q,s)$-entropies in terms of the output entropy, corresponding to the completely mixed input.Comment: 10 pages, no figures. The statement of Proposition 1 is explicitly illustrated with the depolarizing channel. The bibliography is extended and updated. More explanations. To be published in Cent. Eur. J. Phy

Basic concepts in quantum computation

Section headings: 1 Qubits, gates and networks 2 Quantum arithmetic and function evaluations 3 Algorithms and their complexity 4 From interferometers to computers 5 The first quantum algorithms 6 Quantum search 7 Optimal phase estimation 8 Periodicity and quantum factoring 9 Cryptography 10 Conditional quantum dynamics 11 Decoherence and recoherence 12 Concluding remarksComment: 37 pages, lectures given at les Houches Summer School on "Coherent Matter Waves", July-August 199

Characterizing mixing and measurement in quantum mechanics

What fundamental constraints characterize the relationship between a mixture $\rho = \sum_i p_i \rho_i$ of quantum states, the states $\rho_i$ being mixed, and the probabilities $p_i$? What fundamental constraints characterize the relationship between prior and posterior states in a quantum measurement? In this paper we show that there are many surprisingly strong constraints on these mixing and measurement processes that can be expressed simply in terms of the eigenvalues of the quantum states involved. These constraints capture in a succinct fashion what it means to say that a quantum measurement acquires information about the system being measured, and considerably simplify the proofs of many results about entanglement transformation.Comment: 12 page

Challenges for the Development of New Non-Toxic Antifouling Solutions

Marine biofouling is of major economic concern to all marine industries. The shipping trade is particularly alert to the development of new antifouling (AF) strategies, especially green AF paint as international regulations regarding the environmental impact of the compounds actually incorporated into the formulations are becoming more and more strict. It is also recognised that vessels play an extensive role in invasive species propagation as ballast waters transport potentially threatening larvae. It is then crucial to develop new AF solutions combining advances in marine chemistry and topography, in addition to a knowledge of marine biofoulers, with respect to the marine environment. This review presents the recent research progress made in the field of new non-toxic AF solutions (new microtexturing of surfaces, foul-release coatings, and with a special emphasis on marine natural antifoulants) as well as the perspectives for future research directions

Loss of p53 in quaking viable mice leads to Purkinje cell defects and reduced survival

The qkv mutation is a one megabase deletion resulting in abnormal expression of the qkI gene. qkv mice exhibit hypomyelination of the central nervous system and display rapid tremors and seizures as adults. The qkI locus on 6q26-27 has also been implicated as a candidate tumor suppressor gene as the qkI locus maps to a region of genetic instability in Glioblastoma Multiforme (GBM), an aggressive brain tumor of astrocytic lineage. As GBM frequently harbors mutations affecting p53, we crossbred qkv and p53 mutant mice to examine whether qkv mice on a p53−/− background have an increased incidence of GBM. qkv/v; p53−/− mice had a reduced survival rate compared to p53−/− littermates, and the cause of death of the majority of the mice remains unknown. In addition, immunohistochemistry revealed Purkinje cell degeneration in the cerebellum. These results suggest that p53 and qkI are genetically linked for neuronal maintenance and survival

Characterisation of sugar beet (Beta vulgaris L. ssp. vulgaris) varieties using microsatellite markers

<p>Abstract</p> <p>Background</p> <p>Sugar beet is an obligate outcrossing species. Varieties consist of mixtures of plants from various parental combinations. As the number of informative morphological characteristics is limited, this leads to some problems in variety registration research.</p> <p>Results</p> <p>We have developed 25 new microsatellite markers for sugar beet. A selection of 12 markers with high quality patterns was used to characterise 40 diploid and triploid varieties. For each variety 30 individual plants were genotyped. The markers amplified 3-21 different alleles. Varieties had up to 7 different alleles at one marker locus. All varieties could be distinguished. For the diploid varieties, the expected heterozygosity ranged from 0.458 to 0.744. The average inbreeding coefficient F_iswas 0.282 ± 0.124, but it varied widely among marker loci, from F_is= +0.876 (heterozygote deficiency) to F_is= -0.350 (excess of heterozygotes). The genetic differentiation among diploid varieties was relatively constant among markers (F_st= 0.232 ± 0.027). Among triploid varieties the genetic differentiation was much lower (F_st= 0.100 ± 0.010). The overall genetic differentiation between diploid and triploid varieties was F_st= 0.133 across all loci. Part of this differentiation may coincide with the differentiation among breeders' gene pools, which was F_st= 0.063.</p> <p>Conclusions</p> <p>Based on a combination of scores for individual plants all varieties can be distinguished using the 12 markers developed here. The markers may also be used for mapping and in molecular breeding. In addition, they may be employed in studying gene flow from crop to wild populations.</p