Academic statement

 Please provide a concise academic statement of your plans for graduate study, you r career goals, and how MSU's graduate program will help you meet your career and educational objectives.

Why do you want to study Physics at the graduate level?
Describe any research experience, including conferences attended and papers published.
State your area(s) of interest. If you are undecided, list all areas that appeal to you.

 

In the future, I will be a physicist of the most creative scientist. I studied particle physics, which deals with pure quantum mechanical system, and worked in a laboratory, which uses extremely strong laser and generates high energy particles. What I notice from the experiences is that I like to find practical to objects that I apply theories that I learned and found. Solid state physics is appropriate for the purpose because it is easily verified by relatively smaller scale experiments than particle physics and high power laser science as well as knowledge in particle and laser physics is still effective and useful. Moreover, recent discoveries such as graphene and super-solid stimulate my curiosity. My interest is to apply theoretical method to solid state materials and confirm it from experiments in order to understand their physical characteristics.

My first research was neutrino phenomenology and particle detector development in master's course. In neutrino physics, I studied massive neutrinos and their mixing parameters. According to neutrino oscillation experiments, the interaction eigenstates of neutrinos are not the mass eigenstates as well as neutrinos must have non-zero masses. This mixing is similar structure to but much larger than that of quark sector. I assumed a model so called "complex quark-lepton complementarity" and derived the parameters from the model. The model is based on two ideas. One of them is that theoretical frame explaining quark sector, Cabbibo-Kobayashi-Maskawa matrix, is very similar to that of neutrino sector, Pontecorvo-Maki-Nakagawa-Sakata matrix. The matrices are factorized to three elementary rotation matrices(Eulerian rotation matrices) and one complex phase matrix. The other is that each sum of angles corresponding to the same elementary matrix in two mixing matrices is almost pi/4. This is called quark-lepton complementarity model. Because two matrices describe rotations in 3-dimensional complex space, the complementarity can be generalized to 3-dimensional complex space and one of their eigenvectors can be taken as the axis of rotation. After taking the axis, we can determine rotation angles of two matrices around the axis. My argument is two angles have relation similar to Pythagorean theorem. The relation acts as a constraint to mixing angles, so unknown mixing parameters can be derived.

In particle detector project, my task was to design detector chamber and to simulate current signal obtained by detector circuit originated from high energy cosmic ray. The chamber was type of multiwire proportional chamber. I made the chamber design with a computer aided design software. The chamber was operated in vacuum because high voltage was assigned to multi-wire and poor vacuum might cause to air breakdown. To obtain simulated signal, thanked to a simulation code developed by a member in my group, which traced pathes of charged particles induced by cosmic rays in the field, temporal charge signal was interpreted as current, which was converted to oscilloscope waveform after amplifier circuit by circuit simulation program.

The second research was ultra-high power laser experiment. When I was in Advanced Photonics Research Institute, I participated in extremely intensive laser application experiments, which were particle acceleration and secondary radiation generation. In the experiments, my major tasks were to operate detectors and to analyse obtained signal. When a target is irradiated by extremely intensive and short laser pulse, charged particles are accelerated and secondary lights like water window x-ray and x-ray laser are generated by interaction between laser and plasma. To distinguish particle species, we developed Time-of-flight spectrometer and Thomson parabola spectrometer. In the development, I did assemble, examine, calibrate, and operate the detectors and wrote program code to diagnose characteristics of particles: energy, current, temperature, divergence, and spectrum. Another part of my tasks was to produce ultra-thin film of a few nm thickness to use as laser target. I made the film with spin-coating method from an organic polymer and multi-layer film of the polymer and metal with plasma enhanced chemical vapor deposition devices. The film was used as a target to accelerate heavy ions with relativistic kinetic energy. As a minor part of jobs, I was assistant manager of radiation safety: radioisotope management and radiation detector monitoring.

As shown above, I am good at dealing with physical problems by mathematical, computational, and experimental methods because I have experienced both laboratories of theory and experiment. Even though portion for me to perform works related to solid state physics is small, my experience is benefit because when I try to solve a problem, it will allow me to approach different sight of view to traditional ways. Hence, I would propose and perform experiments to prove my theories and arguments.

All in all, I was a generalist who is experienced in many fields: particle, plasma, optics, and nuclear physics and in various methodologies: theoretical, computational, and experimental researches. Now, I want to proceed a specialized physicist studying solid state material or heavy ion acceleration. Solid state physics Explaining my academic objectives concretely, I want to find mathematical structure to understand matters, to compute its physical properties using computational tools such as density functional theory if there is no analytic solution, and to prove it from experiments. My experiences will be helpful to research because broad experiences should give me creative ideas and solutions for the unsolved