Experimental nonlinear sign shift for linear optics quantum computation

We have realized the nonlinear sign shift (NS) operation for photonic qubits.This operation shifts the phase of two photons reflected by a beam splitter using an extra single photon and measurement. We show that the conditional phase shift is $(1.05\pm 0.06) \pi$ in clear agreement with theory. Our results show that by using an ancilla photon and conditional detection, nonlinear optical effects can be implemented using only linear optical elements. This experiment represents an essential step for linear optical implementations of scalable quantum computation.Comment: 4 pages, 4 figure

Control of long-range correlations in turbulence

The character of turbulence depends on where it develops. Turbulence near boundaries, for instance, is different than in a free stream. To elucidate the differences between flows, it is instructive to vary the structure of turbulence systematically, but there are few ways of stirring turbulence that make this possible. In other words, an experiment typically examines either a boundary layer or a free stream, say, and the structure of the turbulence is fixed by the geometry of the experiment. We introduce a new active grid with many more degrees of freedom than previous active grids. The additional degrees of freedom make it possible to control various properties of the turbulence. We show how long-range correlations in the turbulent velocity fluctuations can be shaped by changing the way the active grid moves. Specifically, we show how not only the correlation length but also the detailed shape of the correlation function depends on the correlations imposed in the motions of the grid. Until now, large-scale structure had not been adjustable in experiments. This new capability makes possible new systematic investigations into turbulence dissipation and dispersion, for example, and perhaps in flows that mimic features of boundary layers, free streams, and flows of intermediate character.Comment: This paper has been accepted to Experiments in Fluids. 25 pages, 10 figure

School interaction system

The operation of school system nowadays poses difficulty to users which include teachers, parents and students. For example, the used of paper to keep student attendance can pose a difficulty to the teacher to record and retrieve student's attendance. Not only that, student may easier to forget their homework when they have tones of homeworks given by different teacher from different subjects which cause the student being record in the discipline for not doing homework. Besides that, parents are unavailable during new student registration date which poses difficulty to them too. From the problems mentioned above, I have do survey to get all this information from the parents, student and school staff. In order to solve these problems, I have proposed a new paradigm of web site leveraging on web services named School Interaction System (SIS), which overcomes all these problems. In addition, it also provides both the teacher and parents with up-to-date information about their student/children in term of attendance and homework in the school. With SIS, parents able to check their student/children daily homework and attendance in school. In relation with that, student performance is increased. SIS was implemented within a centralized server whereby schools can just subscribe to the services they want. By doing this, I am also using different testing approach to test SIS in order to achieve the goals and meet the requirements. This may reduce the high maintenance cost and development cost