Department of Physics
http://hdl.handle.net/1721.1/7864
2016-05-27T22:11:26ZLocalization and low temperature transport in disordered one-dimensional systems
http://hdl.handle.net/1721.1/102211
Localization and low temperature transport in disordered one-dimensional systems
Stone, Alfred Douglas
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 1983.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE; Includes bibliographical references.
1983-01-01T00:00:00ZSterile neutrinos in cold climates
http://hdl.handle.net/1721.1/101327
Sterile neutrinos in cold climates
Jones, Benjamin J. P
Measurements of neutrino oscillations at short baselines contain an intriguing set of experimental anomalies that may be suggestive of new physics such as the existence of sterile neutrinos. This three-part thesis presents research directed towards understanding these anomalies and searching for sterile neutrino oscillations. Part I contains a theoretical discussion of neutrino coherence properties. The open-quantum-system picture of neutrino beams, which allows a rigorous prediction of coherence distances for accelerator neutrinos, is presented. Validity of the standard treatment of active and sterile neutrino oscillations at short baselines is verified and non-standard coherence loss effects at longer baselines are predicted. Part II concerns liquid argon detector development for the MicroBooNE experiment, which will search for short-baseline oscillations in the Booster Neutrino Beam at Fermilab. Topics include characterization and installation of the MicroBooNE optical system; test-stand measurements of liquid argon optical properties with dissolved impurities; optimization of wavelength-shifting coatings for liquid argon scintillation light detection; testing and deployment of high-voltage surge arrestors to protect TPC field cages; and software development for optical and TPC simulation and reconstruction. Part III presents a search for sterile neutrinos using the IceCube neutrino telescope, which has collected a large sample of atmospheric-neutrino-induced events in the 1-10 TeV energy range. Sterile neutrinos would modify the detected neutrino flux shape via MSW-resonant oscillations. Following a careful treatment of systematic uncertainties in the sample, no evidence for MSW-resonant oscillations is observed, and exclusion limits on 3+1 model parameter space are derived. Under the mixing assumptions made, the 90% confidence level exclusion limit extends to ... , and the LSND and MiniBooNE allowed regions are excluded at >99% confidence level.
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2015.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 313-339).
2015-01-01T00:00:00ZTheoretical studies for microwave remote sensing of layered random media
http://hdl.handle.net/1721.1/101300
Theoretical studies for microwave remote sensing of layered random media
Zuniga, Michael Anthony
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 1980.; MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.; Vita.; Includes bibliographical references.
1980-01-01T00:00:00ZCumulative effects in quantum algorithms and quantum process tomography
http://hdl.handle.net/1721.1/100678
Cumulative effects in quantum algorithms and quantum process tomography
Hess, Shelby Kimmel
This thesis comprises three results on quantum algorithms and quantum process tomography. In the first section, I create a tool that uses properties of the quantum general adversary bound to upper bound the query complexity of Boolean functions. Using this tool I prove the existence of O(1)-query quantum algorithms for a set of functions called FAULT TREES. To obtain these results, I combine previously known properties of the adversary bound in a new way, as well as extend an existing proof of a composition property of the adversary bound. The second result is a method for characterizing errors in a quantum computer. Many current tomography procedures give inaccurate estimates because they do not have adequate methods for handling noise associated with auxiliary operations. The procedure described here provides two ways of dealing with this noise: estimating the noise independently so its effect can be completely understood, and analyzing the worst case effect of this noise, which gives better bounds on standard estimates. The final section describes a quantum analogue of a classical local search algorithm for Classical k-SAT. I show that for a restricted version of Quantum 2-SAT, this quantum algorithm succeeds in polynomial time. While the quantum algorithm ultimately performs similarly to the classical algorithm, quantum effects, like the observer effect, make the analysis more challenging.
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2014.; Cataloged from PDF version of thesis.; Includes bibliographical references (pages 129-134).
2014-01-01T00:00:00Z