Design, Fabrication and Characterization of a Microwave Resonator ...

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Contents5.2.3 R27 on Silicon . . . . . . . . . . . . . . . . . . . . . . . . . . . . 485.3 Measurements – Yale Design . . . . . . . . . . . . . . . . . . . . . . . . . 505.3.1 R21 on Silicon . . . . . . . . . . . . . . . . . . . . . . . . . . . . 505.3.2 R21 on Sapphire . . . . . . . . . . . . . . . . . . . . . . . . . . . 545.4 Measurement – Design 2: R36 on Silicon . . . . . . . . . . . . . . . . . . 555.5 Discussion of the Experimental Results . . . . . . . . . . . . . . . . . . . 576 Simulations 616.1 Simulations in Sonnet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 616.1.1 Simulations of the Experimentally Realized Results . . . . . . . . . 626.1.2 Additional Designs . . . . . . . . . . . . . . . . . . . . . . . . . . 646.2 Simulations Done at the Institute of Nanoelectronics . . . . . . . . . . . . 667 Conclusion and Outlook 69A Specimen Overview 71B Masks 73B.1 Mask for Rosenberger Connector . . . . . . . . . . . . . . . . . . . . . . . 74B.2 Mask for Probing Station . . . . . . . . . . . . . . . . . . . . . . . . . . . 75Danksagung 85iv
1 Motivation and OutlineQuantum Information Processing is a field with a huge variety of aims, purposes and applications.It includes, among others, the large field of quantum computing, a subject of interestin many research areas.There are some realizations even with superconducting devices (e.g. the charge qubit)or, to stay in the field of solid state physics, quantum dots, realized with semiconductorsand also in the field of atomic physics where individual atoms play the role of quantumtwo-level systems. In liquid nuclear magnetic resonance (NMR) the factorization of 15 wasrealized with seven spin-1/2 nuclei in a molecule used as quantum bits [20]. The calculationwas done with the Shor algorithm which is well known in quantum information theory [17].Beyond the experiments done at different institutes also companies are interested in the fieldof building a quantum computer. Recently D-Wave Systems, Inc., Canada presented theirproposal of a quantum computer in public [1].Although many different qubits have been realized, one central problem in quantum computingis the coupling of qubits, in order to make operations and generate entangled quantumstates. The multidisciplinary field of quantum computing yielded a simple scheme. In quantumoptics quantum computing is realized with atoms placed in a 3d cavity, which has theadvantage of providing a readout scheme for the qubit. Using cavities with wavelengths inthe millimeter regime it is possible to copy this scheme directly to the world of solid statequbits. This idea was realized with quantum dots [15] and proposed for superconductingcharge qubits by Blais et al. [2]. In this work the regimes of zero and large detuning betweenthe artificial atom and the cavity were discussed. In the large detuning regime thelifetime of a qubit will be enhanced and a dispersive quantum non-demolition readout of thequbit will be possible. Also control and entanglement of qubits by using the cavity modes asa ”bus” system is possible. The resonator with a charge qubit inside was realized by Frunzioet al. [6], Wallraff et al. [21] experimentally verified the strong coupling of a qubit and acavity in the resonant and the detuned regime for the first time. The Rabi splitting of theinteraction of the cavity and the qubit was observed. Yang et al. [23] investigated the implementationof entanglement of two Cooper pair boxes within a microwave cavity in detail.They found that the information transfer from one qubit to another can be realized with highfidelity. The cavity has the advantage of working like a magnetic filter, therefore, decoherencecaused by the external environment is strongly suppressed. With frequency matchingit is possible to selectively couple microwave pulses and any particular qubit in the cavity.While these experiments deal with charge qubits a new approach will be done with fluxqubits. This work is a small step into this new field of flux qubits in a cavity. Our aim is toproduce and understand high Q cavities. Later on these will be used for placing a flux qubitinside, in order to compare this type of realization with the one with a charge qubit and toanalyze decoherence and noise effects (e.g. charge noise). A single qubit will be placed in1
Page 6 and 7: 1 Motivation and Outlinethe antinod
Page 8 and 9: 2 Theoretical Description of a CPW
Page 14: 2 Theoretical Description of a CPW
Page 19 and 20: 2.2 Including Superconductivity in
Page 21 and 22: 2.2 Including Superconductivity in
Page 23 and 24: 2.3 Microwave Resonators2.3.2 Quali
Page 25 and 26: 2.3 Microwave ResonatorsFigure 2.11
Page 27 and 28: 2.3 Microwave ResonatorsFigure 2.13
Page 29 and 30: 2.4 The Scattering MatrixThe first
Page 31 and 32: 3 Designs Procedure for the Resonat
Page 33 and 34: 3.3 ConnectorsFigure 3.1: Coupling
Page 35 and 36: 4 Fabrication and Measurement Setup
Page 37 and 38: 4.2 Measurement SetupDevelop Resist
Page 39 and 40: 4.2 Measurement SetupFigure 4.3: Me
Page 41 and 42: 4.3 Calibration4.3 CalibrationIn or
Page 43 and 44: 5 MeasurementsThe first part of thi
Page 45 and 46: 5.1 First Experimentsname design W
Page 47 and 48: 5.2 Measurements - Design 1Figure 5
Page 49 and 50: 5.2 Measurements - Design 1The adva
Page 51 and 52: 5.2 Measurements - Design 15.2.2 R2
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5.2 Measurements - Design 1Figure 5
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5.3 Measurements - Yale DesignFigur
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5.3 Measurements - Yale DesignFigur
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5.4 Measurement - Design 2: R36 on
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5.5 Discussion of the Experimental
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5.5 Discussion of the Experimental
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6 SimulationsThis chapter gives a b
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6.1 Simulations in SonnetFigure 6.4
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6.1 Simulations in SonnetFigure 6.5
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6.2 Simulations Done at the Institu
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7 Conclusion and OutlookThree centr
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A Specimen OverviewDesigns for Rose
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B Masks73
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B.2 Mask for Probing StationB.2 Mas
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Bibliography[1] INFORMATIK: Quanten
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List of Figures2.1 Different realiz
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List of Figures6.6 Forward and back
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List of Tables2.1 Values where (2.1
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DanksagungVor allem möchte ich mic
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Design, Fabrication and Characterization of a Microwave Resonator ...

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