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題名 探討熱屏蔽塗層對量子位元溫度與讀取保真度的影響
Evaluating the Effect of Shielding on Qubit Temperature and Readout Fidelity
作者 呂函諭
Lu, Han-Yu
貢獻者 柯忠廷
Ke, Chung-Ting
呂函諭
Lu, Han-Yu
關鍵詞 超導量子位元
讀取保真度
熱屏蔽塗層
紅外光吸收塗層
有效量子位元溫度
Superconducting qubit
Readout fidelity
Thermal shield coating
IR-absorbing coating
Effective qubit temperature
日期 2025
上傳時間 1-Sep-2025 16:53:16 (UTC+8)
摘要 在發展量子計算技術的過程中，提升讀取保真度（readoutfidelity）是關鍵目標之一。然而，環境中的紅外輻射會引發不必要的態躍遷，從而降低保真度。這類錯誤可分為兩種機率事件，分別為當量子位元被準備於基態卻被測得為激發態的機率P(1|0)，以及準備於激發態卻被測得為基態的機率P(0|1)。 在本論文中，我們在低溫系統之底部裝載（bottom-loading）的屏蔽內側塗上具吸收紅外能力的黑色塗層，比較其對量子位元讀出表現的影響。為進一步理解其背後物理機制，我們亦量測了有效量子位元溫度與相干時間（coherencetimes）隨環境溫度的變化。 我們的研究結果顯示，有黑色塗層的情況下P(1|0)與P(0|1)較低，使讀出保真度由89%提升至93%，證實這種方式確實簡單且有效地降低紅外輻射對單一量子位元的影響，改善我們量測系統的低溫環境。
Achieving high readout fidelity is one of the primary goals in the pursuit of practical quantum computing. However, environmental infrared radiation degrades this fidelity by causing unwanted state transitions. One source of the errors is quantified by P(1|0), the probability of measuring an excited state when a qubit is prepared in the ground state, and P(0|1), the probability of measuring a ground state when prepared in an excited state. In this thesis, we coated the inner surface of the shielding in a cryogenic bottom-loading system with an IR-absorbing black coating and compared its effect on the qubit readout performance. To further understand the underlying physics, we also studied the temperature dependence of the effective qubit temperature and coherence times. Our results show that with the black coating, P(1|0) and P(0|1) were lower, leading to an improved readout fidelity from 89% to 93%. This verifies that this method is indeed a simple and effective way to reduce the effect of infrared radiation on a single qubit, improving the cryogenic environment of our measurement system.
參考文獻 [1] Antti P. Vepsäläinen, Amir H. Karamlou, John L. Orrell, et al. “Impact of ionizing radiation on superconducting qubit coherence.” Nature 584.7822 (Aug. 2020), pp. 551–556 (cit. p. 1). [2] C. Wang, Y. Y. Gao, I. M. Pop, et al. “Measurement and control of quasiparticle dynamics in a superconducting qubit.” Nature Communications 5.1 (Dec. 2014) (cit. pp. 1, 50). [3] Antonio D. Córcoles, Jerry M. Chow, Jay M. Gambetta, et al. “Protecting superconducting qubits from radiation.” Applied Physics Letters 99.18 (Oct. 2011) (cit. p. 1). [4] R. Barends, J. Wenner, M. Lenander, et al. “Minimizing quasiparticle generation from stray infrared light in superconducting quantum circuits.” Applied Physics Letters 99.11 (Sept. 2011) (cit. pp. 1, 28). [5] J. M. Kitzman, J. R. Lane, T. Stefanski, et al. “Vantablack Shielding of Superconducting Qubit Systems.” Journal of Low Temperature Physics 208.5–6 (Jan. 2022), pp. 467–474 (cit. p. 1). [6] Elizaveta I. Malevannaya, Viktor I. Polozov, Anton I. Ivanov, et al. An engineering guide to superconducting quantum circuit shielding. 2025 (cit. p. 1). [7] T. O. Klaassen, J. H. Blok, J. N. Hovenier, et al. “Title of the short paper, if available.” Proceedings of IEEE 10th International Conference on THz Electronics. Cambridge, UK: IEEE, 2002, p. 32 (cit. p. 1). [8] Erik Bründermann, Heinz-Wilhelm Hübers, and Maurice FitzGerald Kimmitt. Terahertz Techniques. Springer Berlin Heidelberg, 2012 (cit. p. 1). [9] D. S. Lvov, S. A. Lemziakov, E. Ankerhold, J. T. Peltonen, and J. P. Pekola. “Thermometry based on a superconducting qubit.” Physical Review Applied 23.5 (May 2025) (cit. pp. 1, 11, 49). [10] K. Serniak, M. Hays, G. de Lange, et al. “Hot Nonequilibrium Quasiparticles in Transmon Qubits.” Physical Review Letters 121.15 (Oct. 2018) (cit. p. 1). [11] X.Y. Jin, A. Kamal, A.P. Sears, et al. “Thermal and Residual Excited-State Population in a 3D Transmon Qubit.” Physical Review Letters 114.24 (June 2015) (cit. pp. 1, 11, 47, 48). [12] Jens Koch, Terri M. Yu, Jay Gambetta, et al. “Charge-insensitive qubit design derived from the Cooper pair box.” Physical Review A 76.4 (Oct. 2007) (cit. pp. 3, 19, 20). [13] Nicholas T. Bronn, Easwar Magesan, Nicholas A. Masluk, et al. “Reducing Spontaneous Emission in Circuit Quantum Electrodynamics by a Combined Readout/Filter Technique.” IEEE Transactions on Applied Superconductivity 25.5 (Oct. 2015), pp. 1–10 (cit. p. 7). [14] R. K. Wangsness. “Sublattice effects in magnetic resonance.” Phys. Rev. 91 (1953), pp. 1085–1091 (cit. p. 10). [15] F. Bloch. “Generalized theory of relaxation.” Phys. Rev. 105 (1957), pp. 1206–1222 (cit. p. 10). [16] R. A. Redfield. “On the theory of relaxation processes.” IBM Journal of Research and Development 1 (1957), pp. 19–31 (cit. p. 10). [17] G. Ithier. “Manipulation, readout and analysis of the decoherence of a superconducting quantum bit.” Ph.D. thesis. Université Pierre et Marie Curie —Paris VI, 2005 (cit. p. 10). [18] G. Ithier, E. Collin, P. Joyez, et al. “Decoherence in a superconducting quantum bit circuit.” Phys. Rev. B 72 (2005), p. 134519 (cit. p. 10). [19] P. Krantz, M. Kjaergaard, F. Yan, et al. “A quantum engineer’s guide to superconducting qubits.” Applied Physics Reviews 6.2 (June 2019) (cit. pp. 11, 12, 19, 20, 22, 36, 50). [20] Hanhee Paik, D. I. Schuster, Lev S. Bishop, et al. “Observation of High Coherence in Josephson Junction Qubits Measured in a Three-Dimensional Circuit QED Architecture.” Physical Review Letters 107.24 (Dec. 2011) (cit. pp. 11, 49, 50). [21] Kyle Serniak. “Nonequilibrium Quasiparticles in Superconducting Qubits.” Ph.D. dissertation. New Haven, CT: Yale University, 2019 (cit. pp. 11, 50). [22] Michael A Nielsen and Isaac L Chuang. Quantum Computation and Quantum Information. Cambridge University Press, 2010 (cit. p. 13). [23] David Isaac Schuster. “Circuit Quantum Electrodynamics.” Ph.D. Thesis. Yale University, May 2007 (cit. pp. 16, 19, 21, 22). [24] M. Göppl, A. Fragner, M. Baur, et al. “Coplanar waveguide resonators for circuit quantum electrodynamics.” Journal of Applied Physics 104.11 (Dec. 2008) (cit. p. 16). [25] Daniel T. Sank. “Fast, Accurate State Measurement in Superconducting Qubits.” ProQuest ID: Sank_ucsb_0035D_12320. Merritt ID: ark:/13030/m5rc23bg. Ph.D. dissertation. University of California, Santa Barbara, 2014 (cit. p. 21). [26] Daniel D. Stancil and Gregory T. Byrd. Principles of Superconducting Quantum Computers. Wiley, Apr. 2022 (cit. p. 21). [27] David M. Pozar. Microwave Engineering. 4th. Hoboken, NJ: Wiley, 2011 (cit. p. 21). [28] Sadman Shanto, Andre Kuo, Clark Miyamoto, et al. “SQuADDS: A validated design database and simulation workflow for superconducting qubit design.” Quantum 8 (Sept. 2024), p. 1465 (cit. p. 21). [29] Zijun Chen. “Metrology of Quantum Control and Measurement in Superconducting Qubits.” PhD thesis. University of California, Santa Barbara, Jan. 2018 (cit. p. 22). [30] Bluefors Oy. User Manual: Bottom Loading Fast Sample Exchange. Version 2.0. Internal documentation provided to customers, not publicly available. Apr. 2021 (cit. pp. 28, 29). [31] Liangyu Chen, Hang-Xi Li, Yong Lu, et al. “Transmon qubit readout fidelity at the threshold for quantum error correction without a quantum-limited amplifier.” npj Quantum Information 9.1 (Mar. 2023) (cit. p. 35). [32] J. Wenner, Yi Yin, Erik Lucero, et al. “Excitation of Superconducting Qubits from Hot Nonequilibrium Quasiparticles.” Physical Review Letters 110.15 (Apr. 2013) (cit. pp. 48, 50). [33] Thomas Connolly, Pavel D. Kurilovich, Spencer Diamond, et al. “Coexistence of Nonequilibrium Density and Equilibrium Energy Distribution of Quasiparticles in a Superconducting Qubit.” Physical Review Letters 132.21 (May 2024) (cit. p. 50). [34] Leonid I. Glazman and Gianluigi Catelani. “Bogoliubov quasiparticles in superconducting qubits.” SciPost Phys. Lect. Notes (2021), p. 31 (cit. p. 50). [35] Pavel D. Kurilovich, Thomas Connolly, Charlotte G. L. Bøttcher, et al. High-frequency readout free from transmon multi-excitation resonances. 2025 (cit. p. 53).
描述 碩士
國立政治大學
應用物理研究所
112755014
資料來源 http://thesis.lib.nccu.edu.tw/record/#G0112755014
資料類型 thesis
dc.contributor.advisor 柯忠廷zh_TW
dc.contributor.advisor Ke, Chung-Tingen_US
dc.contributor.author (Authors) 呂函諭zh_TW
dc.contributor.author (Authors) Lu, Han-Yuen_US
dc.creator (作者) 呂函諭zh_TW
dc.creator (作者) Lu, Han-Yuen_US
dc.date (日期) 2025en_US
dc.date.accessioned 1-Sep-2025 16:53:16 (UTC+8)-
dc.date.available 1-Sep-2025 16:53:16 (UTC+8)-
dc.date.issued (上傳時間) 1-Sep-2025 16:53:16 (UTC+8)-
dc.identifier (Other Identifiers) G0112755014en_US
dc.identifier.uri (URI) https://nccur.lib.nccu.edu.tw/handle/140.119/159398-
dc.description (描述) 碩士zh_TW
dc.description (描述) 國立政治大學zh_TW
dc.description (描述) 應用物理研究所zh_TW
dc.description (描述) 112755014zh_TW
dc.description.abstract (摘要) 在發展量子計算技術的過程中，提升讀取保真度（readoutfidelity）是關鍵目標之一。然而，環境中的紅外輻射會引發不必要的態躍遷，從而降低保真度。這類錯誤可分為兩種機率事件，分別為當量子位元被準備於基態卻被測得為激發態的機率P(1|0)，以及準備於激發態卻被測得為基態的機率P(0|1)。 在本論文中，我們在低溫系統之底部裝載（bottom-loading）的屏蔽內側塗上具吸收紅外能力的黑色塗層，比較其對量子位元讀出表現的影響。為進一步理解其背後物理機制，我們亦量測了有效量子位元溫度與相干時間（coherencetimes）隨環境溫度的變化。 我們的研究結果顯示，有黑色塗層的情況下P(1|0)與P(0|1)較低，使讀出保真度由89%提升至93%，證實這種方式確實簡單且有效地降低紅外輻射對單一量子位元的影響，改善我們量測系統的低溫環境。zh_TW
dc.description.abstract (摘要) Achieving high readout fidelity is one of the primary goals in the pursuit of practical quantum computing. However, environmental infrared radiation degrades this fidelity by causing unwanted state transitions. One source of the errors is quantified by P(1|0), the probability of measuring an excited state when a qubit is prepared in the ground state, and P(0|1), the probability of measuring a ground state when prepared in an excited state. In this thesis, we coated the inner surface of the shielding in a cryogenic bottom-loading system with an IR-absorbing black coating and compared its effect on the qubit readout performance. To further understand the underlying physics, we also studied the temperature dependence of the effective qubit temperature and coherence times. Our results show that with the black coating, P(1|0) and P(0|1) were lower, leading to an improved readout fidelity from 89% to 93%. This verifies that this method is indeed a simple and effective way to reduce the effect of infrared radiation on a single qubit, improving the cryogenic environment of our measurement system.en_US
dc.description.tableofcontents Acknowledgement i 摘要 ii Abstract iii Contents iv List of Figures vii List of Tables viii Chapter 1 Introduction 1 Chapter 2 Theory of Superconducting Qubits 3 2.1 Quantum Harmonic Oscillator 4 2.2 Transmon Qubit 6 2.3 Qubit-resonator Interaction 8 2.4 Decoherence 10 2.4.1 Energy-relaxation Time 𝑇1 11 2.4.2 Dephasing Time 𝑇 ∗ 12 2.5 Qubit Effective Temperature 13 Chapter 3 Qubit Design and Simulation 15 3.1 Transmission Line and Readout Resonator 16 3.2 Qubit 19 3.3 Coupling Strength Between Qubit and Resonator 21 3.4 Purcell Decay Rate 22 3.5 Summary 23 Chapter 4 Experimental Methods 25 4.1 Experimental Setup 26 4.1.1 Qubit Chip Design and Fabrication 26 4.1.2 FSE and Cryogenic Wiring 28 4.1.3 Qubit Control and Readout Electronics 31 4.2 Single Qubit Properties 32 4.3 Single-shot Readout 33 4.3.1 Pulse Schedule, Raw data on the IQ Plane and the Analysis Method 33 4.3.2 Readout Fidelity 35 Chapter 5 Data Analysis 38 5.1 Coating Effect Comparison 39 5.2 Readout Improvement 41 5.2.1 Readout Frequency Calibration 41 5.2.2 Readout Duration 42 5.2.3 Readout Amplitude 44 5.3 Temperature Dependence 47 5.3.1 𝑇𝑒𝑓𝑓 and Probability of Prepared-ground Error 𝑃 (1|0) 47 5.3.2 Coherence Time 49 Chapter 6 Discussion and Future Look 52 6.1 Discussion 52 6.2 Future Work 53 Bibliography 54 Appendix A Eight Resonators 58 Appendix B Coating Effects Comparison of a Neighboring Qubit 60zh_TW
dc.format.extent 7978627 bytes-
dc.format.mimetype application/pdf-
dc.source.uri (資料來源) http://thesis.lib.nccu.edu.tw/record/#G0112755014en_US
dc.subject (關鍵詞) 超導量子位元zh_TW
dc.subject (關鍵詞) 讀取保真度zh_TW
dc.subject (關鍵詞) 熱屏蔽塗層zh_TW
dc.subject (關鍵詞) 紅外光吸收塗層zh_TW
dc.subject (關鍵詞) 有效量子位元溫度zh_TW
dc.subject (關鍵詞) Superconducting qubiten_US
dc.subject (關鍵詞) Readout fidelityen_US
dc.subject (關鍵詞) Thermal shield coatingen_US
dc.subject (關鍵詞) IR-absorbing coatingen_US
dc.subject (關鍵詞) Effective qubit temperatureen_US
dc.title (題名) 探討熱屏蔽塗層對量子位元溫度與讀取保真度的影響zh_TW
dc.title (題名) Evaluating the Effect of Shielding on Qubit Temperature and Readout Fidelityen_US
dc.type (資料類型) thesisen_US
dc.relation.reference (參考文獻) [1] Antti P. Vepsäläinen, Amir H. Karamlou, John L. Orrell, et al. “Impact of ionizing radiation on superconducting qubit coherence.” Nature 584.7822 (Aug. 2020), pp. 551–556 (cit. p. 1). [2] C. Wang, Y. Y. Gao, I. M. Pop, et al. “Measurement and control of quasiparticle dynamics in a superconducting qubit.” Nature Communications 5.1 (Dec. 2014) (cit. pp. 1, 50). [3] Antonio D. Córcoles, Jerry M. Chow, Jay M. Gambetta, et al. “Protecting superconducting qubits from radiation.” Applied Physics Letters 99.18 (Oct. 2011) (cit. p. 1). [4] R. Barends, J. Wenner, M. Lenander, et al. “Minimizing quasiparticle generation from stray infrared light in superconducting quantum circuits.” Applied Physics Letters 99.11 (Sept. 2011) (cit. pp. 1, 28). [5] J. M. Kitzman, J. R. Lane, T. Stefanski, et al. “Vantablack Shielding of Superconducting Qubit Systems.” Journal of Low Temperature Physics 208.5–6 (Jan. 2022), pp. 467–474 (cit. p. 1). [6] Elizaveta I. Malevannaya, Viktor I. Polozov, Anton I. Ivanov, et al. An engineering guide to superconducting quantum circuit shielding. 2025 (cit. p. 1). [7] T. O. Klaassen, J. H. Blok, J. N. Hovenier, et al. “Title of the short paper, if available.” Proceedings of IEEE 10th International Conference on THz Electronics. Cambridge, UK: IEEE, 2002, p. 32 (cit. p. 1). [8] Erik Bründermann, Heinz-Wilhelm Hübers, and Maurice FitzGerald Kimmitt. Terahertz Techniques. Springer Berlin Heidelberg, 2012 (cit. p. 1). [9] D. S. Lvov, S. A. Lemziakov, E. Ankerhold, J. T. Peltonen, and J. P. Pekola. “Thermometry based on a superconducting qubit.” Physical Review Applied 23.5 (May 2025) (cit. pp. 1, 11, 49). [10] K. Serniak, M. Hays, G. de Lange, et al. “Hot Nonequilibrium Quasiparticles in Transmon Qubits.” Physical Review Letters 121.15 (Oct. 2018) (cit. p. 1). [11] X.Y. Jin, A. Kamal, A.P. Sears, et al. “Thermal and Residual Excited-State Population in a 3D Transmon Qubit.” Physical Review Letters 114.24 (June 2015) (cit. pp. 1, 11, 47, 48). [12] Jens Koch, Terri M. Yu, Jay Gambetta, et al. “Charge-insensitive qubit design derived from the Cooper pair box.” Physical Review A 76.4 (Oct. 2007) (cit. pp. 3, 19, 20). [13] Nicholas T. Bronn, Easwar Magesan, Nicholas A. Masluk, et al. “Reducing Spontaneous Emission in Circuit Quantum Electrodynamics by a Combined Readout/Filter Technique.” IEEE Transactions on Applied Superconductivity 25.5 (Oct. 2015), pp. 1–10 (cit. p. 7). [14] R. K. Wangsness. “Sublattice effects in magnetic resonance.” Phys. Rev. 91 (1953), pp. 1085–1091 (cit. p. 10). [15] F. Bloch. “Generalized theory of relaxation.” Phys. Rev. 105 (1957), pp. 1206–1222 (cit. p. 10). [16] R. A. Redfield. “On the theory of relaxation processes.” IBM Journal of Research and Development 1 (1957), pp. 19–31 (cit. p. 10). [17] G. Ithier. “Manipulation, readout and analysis of the decoherence of a superconducting quantum bit.” Ph.D. thesis. Université Pierre et Marie Curie —Paris VI, 2005 (cit. p. 10). [18] G. Ithier, E. Collin, P. Joyez, et al. “Decoherence in a superconducting quantum bit circuit.” Phys. Rev. B 72 (2005), p. 134519 (cit. p. 10). [19] P. Krantz, M. Kjaergaard, F. Yan, et al. “A quantum engineer’s guide to superconducting qubits.” Applied Physics Reviews 6.2 (June 2019) (cit. pp. 11, 12, 19, 20, 22, 36, 50). [20] Hanhee Paik, D. I. Schuster, Lev S. Bishop, et al. “Observation of High Coherence in Josephson Junction Qubits Measured in a Three-Dimensional Circuit QED Architecture.” Physical Review Letters 107.24 (Dec. 2011) (cit. pp. 11, 49, 50). [21] Kyle Serniak. “Nonequilibrium Quasiparticles in Superconducting Qubits.” Ph.D. dissertation. New Haven, CT: Yale University, 2019 (cit. pp. 11, 50). [22] Michael A Nielsen and Isaac L Chuang. Quantum Computation and Quantum Information. Cambridge University Press, 2010 (cit. p. 13). [23] David Isaac Schuster. “Circuit Quantum Electrodynamics.” Ph.D. Thesis. Yale University, May 2007 (cit. pp. 16, 19, 21, 22). [24] M. Göppl, A. Fragner, M. Baur, et al. “Coplanar waveguide resonators for circuit quantum electrodynamics.” Journal of Applied Physics 104.11 (Dec. 2008) (cit. p. 16). [25] Daniel T. Sank. “Fast, Accurate State Measurement in Superconducting Qubits.” ProQuest ID: Sank_ucsb_0035D_12320. Merritt ID: ark:/13030/m5rc23bg. Ph.D. dissertation. University of California, Santa Barbara, 2014 (cit. p. 21). [26] Daniel D. Stancil and Gregory T. Byrd. Principles of Superconducting Quantum Computers. Wiley, Apr. 2022 (cit. p. 21). [27] David M. Pozar. Microwave Engineering. 4th. Hoboken, NJ: Wiley, 2011 (cit. p. 21). [28] Sadman Shanto, Andre Kuo, Clark Miyamoto, et al. “SQuADDS: A validated design database and simulation workflow for superconducting qubit design.” Quantum 8 (Sept. 2024), p. 1465 (cit. p. 21). [29] Zijun Chen. “Metrology of Quantum Control and Measurement in Superconducting Qubits.” PhD thesis. University of California, Santa Barbara, Jan. 2018 (cit. p. 22). [30] Bluefors Oy. User Manual: Bottom Loading Fast Sample Exchange. Version 2.0. Internal documentation provided to customers, not publicly available. Apr. 2021 (cit. pp. 28, 29). [31] Liangyu Chen, Hang-Xi Li, Yong Lu, et al. “Transmon qubit readout fidelity at the threshold for quantum error correction without a quantum-limited amplifier.” npj Quantum Information 9.1 (Mar. 2023) (cit. p. 35). [32] J. Wenner, Yi Yin, Erik Lucero, et al. “Excitation of Superconducting Qubits from Hot Nonequilibrium Quasiparticles.” Physical Review Letters 110.15 (Apr. 2013) (cit. pp. 48, 50). [33] Thomas Connolly, Pavel D. Kurilovich, Spencer Diamond, et al. “Coexistence of Nonequilibrium Density and Equilibrium Energy Distribution of Quasiparticles in a Superconducting Qubit.” Physical Review Letters 132.21 (May 2024) (cit. p. 50). [34] Leonid I. Glazman and Gianluigi Catelani. “Bogoliubov quasiparticles in superconducting qubits.” SciPost Phys. Lect. Notes (2021), p. 31 (cit. p. 50). [35] Pavel D. Kurilovich, Thomas Connolly, Charlotte G. L. Bøttcher, et al. High-frequency readout free from transmon multi-excitation resonances. 2025 (cit. p. 53).zh_TW