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Decoherence and Error Correction: Topics in Quantum Computing
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| 자료유형 | 학위논문 |
|---|---|
| 서명/저자사항 | Decoherence and Error Correction: Topics in Quantum Computing. |
| 개인저자 | Premakumar, Vickram Narayn. |
| 단체저자명 | The University of Wisconsin - Madison. Physics. |
| 발행사항 | [S.l.]: The University of Wisconsin - Madison., 2019. |
| 발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
| 형태사항 | 127 p. |
| 기본자료 저록 | Dissertations Abstracts International 81-04B. Dissertation Abstract International |
| ISBN | 9781687929648 |
| 학위논문주기 | Thesis (Ph.D.)--The University of Wisconsin - Madison, 2019. |
| 일반주기 |
Source: Dissertations Abstracts International, Volume: 81-04, Section: B.
Advisor: Joynt, Robert J. |
| 이용제한사항 | This item must not be sold to any third party vendors.This item must not be sold to any third party vendors. |
| 요약 | This dissertation investigates problems concerning decoherence and error correction in quantum computer architectures. First we discuss Evanescent-Wave Johnson Noise as a decoherence mechanism. A classical analogy between the Green's functions relevant to describing this noise is used in order to simplify calculations and present results focusing on geometries relevant for small devices. We apply this to model qubit decoherence in the presence of EWJN showing that it could be the dominant noise mechanism for spin qubits in magnetic fields around 1T.We then turn our attention to characterizing spatial noise correlations in existing qubit devices and strategies to optimize circuit design using correlation information. The concept can be viewed as a Ramsey experiment conducted in a two-dimensional product qubit subspace, allowing us to use many single qubit noise spectroscopy techniques to measure spatial correlations. This is a generalization of decoherence-free subspaces, which have been studied substantially as passive error correction. Next, we describe how to use knowledge of the correlations to choose the best circuit out of many candidates for doing a particular task. The proposed metrics produce predictions on which circuit will result in the highest fidelity under a given noise model, which we verify using numerical simulations. We demonstrate that a known procedure for coherent-error correction can be made fault tolerant by insisting that C_kNOT gates occur in a single time step. Justification for the simulation of these gates via classical ancillas combined with the Gottesman-Knill theorem is presented by proving that the ancilla and data registers are separable before correction operations. We produce a threshold for an example code on the same order of magnitude as previous work, but with a refined implementation that is fault tolerant. We continue with the use of redundant syndrome extraction in stabilizer codes to circumvent majority-rules decision making for conditional operations. We produce simulations comparing the two schemes across a range of models characterized by the independent error rates on qubits and measurements. The most robust realization of this scheme for several codes resemble balanced incomplete block designs, and we explore this correspondence towards generating new codes from designs. |
| 일반주제명 | Physics. Quantum physics. Condensed matter physics. |
| 언어 | 영어 |
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