Quantum walk as a generalized measuring device

We show that a one-dimensional discrete time quantum walk can be used to implement a generalized measurement in terms of positive operator value measure (POVM) on a single qubit. More precisely, we show that for a single qubit any set of rank 1 and rank 2 POVM elements can be generated by a properly engineered quantum walk. In such a scenario the measurement of particle at position x=i corresponds to a measurement of a POVM element E_i on a qubit. We explicitly construct quantum walks implementing unambiguous state discrimination and SIC-POVM.Comment: 6 pages, 1 figur

Pembuatan Ultra High Strength Concrete Dengan Material Lokal

Ultra High Strength Concrete (UHSC) merupakan terobosan yang sedang dikembangkan dalam beberapa dekade terakhir ini. UHSC memiliki beberapa kelebihan dibandingkan Normal Strength Concrete (NSC), yaitu beton UHSC memiliki ketahanan yang lebih baik terhadap asam, kebakaran, maupun ketahanan jangka panjang. Pada tahun 2010, di Indonesia telah dapat dibuat beton UHSC dengan kekuatan mencapai 140 MPa dengan memanfaatkan material lokal dengan ukuran yang sangat halus walaupun masih di laboratorium. Dalam penelitian ini akan dicari mix design yang dapat mencapai kuat tekan UHSC, pengaruh steam curing, penambahan steel fibres, dan proses vacuum dalam pembuatan UHSC.Pencarian mix design dilakukan terebih dahulu sebelum melakukan penelitian yang lain. Kuat tekan maksimum yang dicapai adalah sebesar 115 MPa pada umur 28 hari. Perlakuan steam curing memberikan pengaruh pada kuat tekan awal dan dengan melakukan proses vacuum dalam proses pemadatan benda uji tidak memberikan pengaruh dalam kekuatan. Penambahan steel fibres memberikan pengaruh yang baik dari segi ketahan dalam mengatasi keruntuhan yang getas

Finite Mixture Analysis of Beauty-Contest Data from Multiple Samples

This paper develops a finite mixture distribution analysis of Beauty- Contest data obtained from diverse groups of experiments. ML estimation using the EM approach provides estimates for the means and variances of the component distributions, which are common to all the groups, and estimates of the mixing proportions, which are specific to each group. This estimation is performed without imposing constraints on the parameters of the composing distributions. The statistical analysis indicates that many individuals follow a common pattern of reasoning described as iterated best reply (degenerate), and shows that the proportions of people thinking at different levels of depth vary across groups.Beauty-Contest experiments, reasoning hierarchy, finite mixture distribution, EM algorithm

Effect of multiple reusing of simulated air showers in detector simulations

The study of high energy cosmic rays requires detailed Monte Carlo simulations of both, extensive air showers and the detectors involved in their detection. In particular, the energy calibration of several experiments is obtained from simulations. Also, in composition studies simulations play a fundamental role because the primary mass is determined by comparing experimental with simulated data. At the highest energies the detailed simulation of air showers is very costly in processing time and disk space due to the large number of secondary particles generated in interactions with the atmosphere. Therefore, in order to increase the statistics, it is quite common to recycle single showers many times to simulate the detector response. As a result, the events of the Monte Carlo samples generated in this way are not fully independent. In this work we study the artificial effects introduced by the multiple use of single air showers for the detector simulations. In particular, we study in detail the effects introduced by the repetitions in the kernel density estimators which are frequently used in composition studies.Comment: 15 pages and 4 figure

The Spectator Electromagnetic Effect on Charged Pion Spectra in Peripheral Ultrarelativistic Heavy-Ion Collisions

We estimate the electromagnetic effect of the spectator charge on the momentum spectra of $\pi^+$ and $\pi^-$ produced in peripheral Pb+Pb collisions at SPS energies. We find that the effect is large and results in strongly varying structures in the $x_F$ dependence of the $\pi^+/\pi^-$ ratio, especially at low transverse momenta where a deep valley in the above ratio is predicted at $x_F \sim$ 0.15 -- 0.20. It appears that the effect depends on initial conditions. Thus, it provides new information on the space and time evolution of the non-perturbative pion creation process.Comment: 20 pages and 8 figure

Internal Structure and Environmental Significance of a Perennial Snowbank, Melville Island, N.W.T.

A perennial snowbank located in the continuous permafrost zone was cored to obtain details of its internal structure and history. In spring the snowbank is up to 10 m thick and composed of deep snow accumulated during the previous winter, overlying ice developed by basal ice accretion over many years. The perennial ice exhibits a layered structure with alternating clear and milky bands and contains randomly oriented, variably shaped bubbles. Horizons of aeolian and mudflow deposits occur at irregular intervals and correspond to periods of aggradation and thaw truncation of the snowbank. Tritium concentrations in a core from the deepest portion of the snowbank indicate that the basal 2 m of ice pre-dates 1957. Other layers of ice likely represent precipitation that fell between 1958 and 1962, between 1968 and 1976, and after 1983. Ice developed during the 1963 atmospheric tritium peak is no longer present. Energy balance measurements indicate that potential climatic warming is unlikely to eliminate the perennial portion of the snowbank unless accompanied by substantially less snow drifting at the site.Key words: snowbank ice, tritium, climate changeMots clés: glace de congère, tritium, changement de clima