5,440 research outputs found

    Non-perturbative gadget for topological quantum codes

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    Many-body entangled systems, in particular topologically ordered spin systems proposed as resources for quantum information processing tasks, often involve highly non-local interaction terms. While one may approximate such systems through two-body interactions perturbatively, these approaches have a number of drawbacks in practice. Here, we propose a scheme to simulate many-body spin Hamiltonians with two-body Hamiltonians non-perturbatively. Unlike previous approaches, our Hamiltonians are not only exactly solvable with exact ground state degeneracy, but also support completely localized quasi-particle excitations, which are ideal for quantum information processing tasks. Our construction is limited to simulating the toric code and quantum double models, but generalizations to other non-local spin Hamiltonians may be possible.Comment: 13 pages, 8 figures, PRL Accepte

    Discussion of “effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity”

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    We read with great interest a recent article by Georgescu et al. (2017) entitled “Effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity”. The authors aimed to investigate effects of hydration and rehydration by using sensitive indirect measures of oxidative stress and the antioxidant capacity response. In this study, they evaluated concentrations of plasma osmolality, Trolax equivalent antioxidant capacity (TEAC), and ferric reducing ability of plasma (FRAP) in a sample of athletes during pre-exercise, immediately postexercise, and 1 h after full rehydration. As stated in statistical analysis and also abstract of the article, the authors used 1-way ANOVA to compare differences in means of numerical variables (i.e., concentrations of plasma osmolality, TEAC, and FRAP) of different time-points of measurement. Since they investigated the same sample of participants in each group during different time-points (i.e., pre-exercise, immediately postexercise, and 1 h after full rehydration), their measurements are completely dependent (Farrokhi and Peykanpour 2017a; Farrokhi and Shirian 2017; Farrokhi et al. 2017). ANOVA and Kruskal–Wallis test are used for comparison of the means of more than 2 independent groups (Gaddis 1998; Farrokhi 2017b; Farrokhi and Arjaki 2017; Farrokhi and Peykanpour 2017b). Therefore, after assessment of the normal distribution of studied quantitative variables, including concentrations of plasma osmolality, TEAC, and FRAP, the authors must use repeated-measures ANOVA or Friedman test for comparison of the means of each variable at pre-exercise, immediately postexercise, and 1 h after full rehydration (Farrokhi 2017a; Farrokhi and Amani-Beni 2017). Furthermore, they must use Wilcoxon test and paired t test for comparison of concentrations of plasma osmolality, TEAC, and FRAP between 2 time-points of measurement

    Polaron cross-overs and d-wave superconductivity in Hubbard-Holstein model

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    We present a theoretical study of superconductivity of polarons in the Hubbard-Holstein model. A residual kinematic interaction proportional to the square of the polaron hopping energy between polarons and phonons provides a pairing field for the polarons. We find that superconducting instability in the d-wave channel is possible with small transition temperatures which is maximum in the large to small polaron cross-over region. An s-wave instability is found to be not possible when the effective on-site interaction between polarons is repulsive

    Quantum codes give counterexamples to the unique pre-image conjecture of the N-representability problem

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    It is well known that the ground state energy of many-particle Hamiltonians involving only 2-body interactions can be obtained using constrained optimizations over density matrices which arise from reducing an N-particle state. While determining which 2-particle density matrices are "N- representable" is a computationally hard problem, all known extreme N-representable 2-particle reduced density matrices arise from a unique N-particle pre-image, satisfying a conjecture established in 1972. We present explicit counterexamples to this conjecture through giving Hamiltonians with 2-body interactions which have degenerate ground states that cannot be distinguished by any 2-body operator. We relate the existence of such counterexamples to quantum error correction codes and topologically ordered spin systems.Comment: 4 pages, 1 figur

    Synthesis of β-triphosphotriester pronucleotides

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    Dinucleoside phosphorochloridite were synthesized from phosphorus trichloride and three nucleoside analogues, 3-fluoro-2,3-dideoxythymidine (FLT), 2\u27,3\u27-dideoxy-5-fluoro-3\u27- thiacytidine (FTC), and 2\u27,3\u27-dideoxy-3\u27-thiacytidine (3TC), in a multistep synthesis. Polymerbound N-Boc p-acetoxybenzyl 5¢-O-2¢-deoxythymidine was reacted with dinucleoside phosphorochloridite in the presence of 2,6-lutidine, followed by the reaction with dodecyl alcohol and 5-(ethylthio)-1H-tetrazole, oxidation with tert-butyl hydroperoxide, and acidic cleavage, respectively, to afford the b-triphosphotriester derivatives containing three different nucleosides

    Framework for classifying logical operators in stabilizer codes

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    Entanglement, as studied in quantum information science, and non-local quantum correlations, as studied in condensed matter physics, are fundamentally akin to each other. However, their relationship is often hard to quantify due to the lack of a general approach to study both on the same footing. In particular, while entanglement and non-local correlations are properties of states, both arise from symmetries of global operators that commute with the system Hamiltonian. Here, we introduce a framework for completely classifying the local and non-local properties of all such global operators, given the Hamiltonian and a bi-partitioning of the system. This framework is limited to descriptions based on stabilizer quantum codes, but may be generalized. We illustrate the use of this framework to study entanglement and non-local correlations by analyzing global symmetries in topological order, distribution of entanglement and entanglement entropy.Comment: 20 pages, 9 figure

    Desain Sistem Pendingin Ruang Muat Kapal Ikan Tradisional Dengan Menggunakan Campuran Es Kering Dan Cold Ice Yang Berbahan Dasar Propylene Glycol

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    Penanganan ikan hasil perikanan supaya tetap segar biasanya menggunakan es basah, terutama oleh nelayan tradisional. Penggunaan es basah hanya bertahan dalam waktu singkat. Propylene glycol merupakan salah satu bahan yang mampu menjaga kestabilan suhu rendah. Sehingga sangat efektif dan efisien apabila digunakan sebagai bahan pendingin ikan. Selain tidak membutuhkan tempat yang luas dalam penyimpanannya, propylene glycol mampu mempertahankan suhu rendah dalam waktu yang lama, tidak beracun dan mudah didegradasi oleh lingkungan (ramah lingkungan). Penelitian ini dilakukan untuk mengetahui lama waktu yang dicapai alat pendingin dengan penambahan uap es kering dan propylene glycol. Serta mengetahui mutu ikan dengan menggunakan sistem pendingin yang dirancang dengan bahan dasar propylene glycol. Sistem pendingin ini dirancang dengan menggunakan cool box yang terdiri dari dua box yang terpisah. Coolbox yang pertama sebagai tempat ikan dengan es basah. Coolbox yang ke dua (yang lebih kecil) sebagai tempat es kering dan propylene glycol. Uap dingin dari es kering dan propylene glycol dialirkan ke kotak yang pertama dengan menggunakan blower. Sistem pendingin yang dirancang ini akan mampu mempertahankan suhu rendah dan menjaga kualitas ikan hasil tangkapan tetap segar. Sehingga sistem pendingin yang berbahan dasar propylene glycol akan lebih efektif, efisien dan ramah lingkungan

    Chaos in quantum channels

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    We study chaos and scrambling in unitary channels by considering their entanglement properties as states. Using out-of-time-order correlation functions to diagnose chaos, we characterize the ability of a channel to process quantum information. We show that the generic decay of such correlators implies that any input subsystem must have near vanishing mutual information with almost all partitions of the output. Additionally, we propose the negativity of the tripartite information of the channel as a general diagnostic of scrambling. This measures the delocalization of information and is closely related to the decay of out-of-time-order correlators. We back up our results with numerics in two non-integrable models and analytic results in a perfect tensor network model of chaotic time evolution. These results show that the butterfly effect in quantum systems implies the information-theoretic definition of scrambling

    Perancangan Sistem Pengolahan Data Jemaat Berbasis Web pada Gereja Gkpi Kota Jambi

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    The data processing systems is a very necessary way to manipulate a data into useful information. The system makes data storage, adding, changing, scheduling to reporting well integrated, so that it can help parts to exchange information and make decisions quickly. The problems faced by GKPI Pal Merah Jambi are currently still using Microsoft Office Word and in disseminating information such as worship schedules, church activities and other worship routines through paper and wall-based worship services. To print worship and report reports requires substantial operational funds, in addition to data collection and storage there are still deficiencies including recording data on the book, difficulty in processing large amounts of data and stored in only one special place that is passive. Based on the above problems, the author is interested in conducting research with the title Designing Data Processing Systems for Web-Based Churches in the GKPI Pal Merah Church in Jambi. The purpose of this study is to design and produce a data processing system for the church. Using this system can facilitate data processing in the GKPI Pal Merah Jambi Church. This study uses a waterfall development method, a method that provides a systematic and sequential approach to system needs analysis, design, implementation and unit testing, system testing and care. Applications built using the web with MySQL DBMS database, PHP programming language and Laravel
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