Stories Summer2013

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Superconductors from pyrolysis, erasing quantum information and reincarting historic experiments in the Physlab: Summer Research Program 2013

The spin physics group of physics lab continued its tradition of offering internship to students. Students from computer science department, electrical engineering and physics department worked on different projects including experiments with photon detection, exploring the strange phenomenon of quantum erasure, ellipsometry of electro-deposited magnetic films, automation and computer control of latent heat of vaporization of LN2 experiment, synthesis of superconductors, detection of phase transitions using GMR sensors and the Romer's astronomical measurements of the speed of light.

These students were supervised by Dr. Muhammad Sabieh Anwar, Hassaan Majeed, Murtaza Saleem and Amrozia Shaheen.
High temperature superconductors made by pyrolysis: Muhammad Zaki Javaid synthesized a high temperature superconductor using a partially modified citrate pyrolysis method. This involved chemically synthesizing the required compound (Yttrium Barium Copper Oxide) in various mediums, followed by annealing in the presence of oxygen. The superconductors exhibited the famous Meissner effect. Later, Zaki went to to test a tunneling magnetoresistance sensor for detection of flux expulsion from a superconductor. Outcome: New experiment for Lab 2 is currently being written up.
Single photon counting and down conversion: Muhammad Ashad Azam explored the process of spontaneous parametric down conversion, a process by which a single photon produces two 'entangled' photons, which can then be used in single photon experiments. The process of type-II down conversion from a beta-barium borate crystal was studied in detail and down converted photons were successfully detected. A number of complementary experiments were done along the way such as measuring the dark counts, looking at characteristics of avalanche photodetectors and verifying Poissonian statistics of detected photons. Outcome: The work continues.
Quantum erasure: Hamid Suleman, a shophomore student started his work from Michelson Interferometer, an existing experiment in the advance physics laboratory. Hamid then built a Mach-Zehnder interferometer and verified the cosine squared dependence of intensity, measured the refractive index of a piece of glass inserted in one arm of the interferometer, observed and recorded the effects of obtaining which way information and concluded that any attempt to extract which way information destroyed the interference pattern. This is the classic version of a strange quantum phenomenon called quantum erasure. Outcome: Experiment for the advanced physics lab and pedagogical article.
Ellipsometry of magnetic field assisted electro-deposited films: Hamza Qureshi, a physics major, worked on electro-depositing nickel films in the presence of magnetic fields. The goal was to control and understand the size and thickness dependent orientation of the magnetization of these films. The grown films were observed under optical microscopes and their thickness were determined using ellipsometry, Finally, MOKE signals were acquired using the homemade assemblies, under different configurations of the ambient magnetic field. Also see the Hunerkada presentation: Ellipsometry of electro-deposited magnetic thin films. Outcome: Ongoing research.
Muhammad Faraz's primary task was to reproduce the results of the recently developed Freshmen Lab experiments. These experiments include the testing of Hall effect experiment, b) Testing of Franck-Hertz's experiment, (c) The magic eye experiment. As a secondary assignment he had to automate the latent heat of vaporization of liquid nitrogen experiment latent heat of liquid nitrogen experiment. For that a computer interfaced electronic balance was used along with the Labview software. The results matched with the published value of latent heat of LN2. Outcome: testing of newly built experiments.
Reproducing Roemer's determination of the speed of light: Mustafa Afzal Saeed spent this June all about appreciating the simplest of techniques to provide the answer to the toughest of conundrums. He worked on reconstructing Ole Roemer's technique to calculate the speed of light. The technique comprised of measuring the variations in the apparent periods of Io (one of Jupiter's moons), calculating the distance between Earth and Jupiter at those respective measurements, and calculating the speed of light by dividing the extra distance the Earth moves between successive observations of Io, by the additional time Io took to complete one period. The subsequent Matlab Program that was created churned up a value of 'c' which was 85% of its actual value. This project, however, will be refined and polished in the months to come. Outcome: Work continues.
Catching the decay of muons: A computer science major, Hassaan Mubasher, has been busy this semester detecting muons. These muons traverse a trio of scintillators and decay, producing characteristic flashes that are detected by photomultiplier tubes. The signals are then routed into timing, logic, coincidence units and multi channel analyzers. The experimental data is processed and analyzed, looking for signature muon events. Outcome: Experiment for the advanced physics lab. Outcome: Write-up is in progress.
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