Qubit decoherence from two-level fluctuators –– A numerical and analytical exploration

In solid-state environments, qubit operations are susceptible to charge noise. It couples to the detuning and tunnel coupling parameters in the qubit, which become significant contributors to decoherence, therefore emphasizing the need to better characterize noise in qubits for achieving high-fideli...

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Main Author: Chong, Geraldine Kah Min
Other Authors: Koh Teck Seng
Format: Thesis-Master by Coursework
Language:English
Published: Nanyang Technological University 2024
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Online Access:https://hdl.handle.net/10356/179132
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-1791322024-07-22T15:36:15Z Qubit decoherence from two-level fluctuators –– A numerical and analytical exploration Chong, Geraldine Kah Min Koh Teck Seng School of Physical and Mathematical Sciences kohteckseng@ntu.edu.sg Physics Qubit decoherence Charge noise Gaussian noise Two-level fluctuator Random telegraph process In solid-state environments, qubit operations are susceptible to charge noise. It couples to the detuning and tunnel coupling parameters in the qubit, which become significant contributors to decoherence, therefore emphasizing the need to better characterize noise in qubits for achieving high-fidelity qubit gate operations. Many previous studies of charge noise go on a few assumptions, namely: (1) It is Gaussian- distributed, which results in qubit decoherence following a Gaussian decay, and (2) it is dominant in the detuning parameter, with noise in the tunnelling parameter taken to be negligible due to it being several orders of amplitudes smaller. While these are good approximations, studies have found that certain situations arise whereby charge noise has a non-Gaussian distribution, or in which noise in the tunnelling parameter dominates over noise in the detuning. In this thesis, we adopted a more general approach to studying noise by making fewer assumptions about noise and starting from the simplest noise model of a two-level fluctuator. We implemented numerical simulations of qubit decoherence due to noise modelled from two-level fluctuators, which are a source of charge noise. Further analysis of the decoherence results was also performed, and to better characterize the obtained results, we derived analytical expressions for the qubit state, r(t), and explored an extended parameter space. Master's degree 2024-07-21T23:51:55Z 2024-07-21T23:51:55Z 2024 Thesis-Master by Coursework Chong, G. K. M. (2024). Qubit decoherence from two-level fluctuators –– A numerical and analytical exploration. Master's thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/179132 https://hdl.handle.net/10356/179132 en application/pdf Nanyang Technological University
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Physics
Qubit decoherence
Charge noise
Gaussian noise
Two-level fluctuator
Random telegraph process
spellingShingle Physics
Qubit decoherence
Charge noise
Gaussian noise
Two-level fluctuator
Random telegraph process
Chong, Geraldine Kah Min
Qubit decoherence from two-level fluctuators –– A numerical and analytical exploration
description In solid-state environments, qubit operations are susceptible to charge noise. It couples to the detuning and tunnel coupling parameters in the qubit, which become significant contributors to decoherence, therefore emphasizing the need to better characterize noise in qubits for achieving high-fidelity qubit gate operations. Many previous studies of charge noise go on a few assumptions, namely: (1) It is Gaussian- distributed, which results in qubit decoherence following a Gaussian decay, and (2) it is dominant in the detuning parameter, with noise in the tunnelling parameter taken to be negligible due to it being several orders of amplitudes smaller. While these are good approximations, studies have found that certain situations arise whereby charge noise has a non-Gaussian distribution, or in which noise in the tunnelling parameter dominates over noise in the detuning. In this thesis, we adopted a more general approach to studying noise by making fewer assumptions about noise and starting from the simplest noise model of a two-level fluctuator. We implemented numerical simulations of qubit decoherence due to noise modelled from two-level fluctuators, which are a source of charge noise. Further analysis of the decoherence results was also performed, and to better characterize the obtained results, we derived analytical expressions for the qubit state, r(t), and explored an extended parameter space.
author2 Koh Teck Seng
author_facet Koh Teck Seng
Chong, Geraldine Kah Min
format Thesis-Master by Coursework
author Chong, Geraldine Kah Min
author_sort Chong, Geraldine Kah Min
title Qubit decoherence from two-level fluctuators –– A numerical and analytical exploration
title_short Qubit decoherence from two-level fluctuators –– A numerical and analytical exploration
title_full Qubit decoherence from two-level fluctuators –– A numerical and analytical exploration
title_fullStr Qubit decoherence from two-level fluctuators –– A numerical and analytical exploration
title_full_unstemmed Qubit decoherence from two-level fluctuators –– A numerical and analytical exploration
title_sort qubit decoherence from two-level fluctuators –– a numerical and analytical exploration
publisher Nanyang Technological University
publishDate 2024
url https://hdl.handle.net/10356/179132
_version_ 1806059834286538752