Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 253 for “"qubits"”.
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Quantum Cryptography Beyond Qubits
… schemes, analogous to classical bits, known as qubits. Nevertheless, other than for the polarization of light, photonic degrees of freedom, i.e. position, momentum, time and frequency, naturally occur as high-dimensional quantum systems. Moreover, by considering high-dimensional encoding schemes …
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Engineering Noise-Protected Superconducting Qubits
Improving the lifetime of qubits is crucial to achieve reliable quantum computation with superconducting qubits. One way to improve the qubit lifetime is to engineer the circuit design and the parameters to protect the qubit from environmental noise. Some of the noise-protected superconducting …
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Novel Gates with Superconducting Fluxonium Qubits
Over the past two decades, superconducting qubits have emerged as a leading platform for gate-based quantum computation. Despite tremendous technological advancements, errors accumulating during gate operations are still a major bottleneck toward building a robust quantum computer. In general, …
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Waveguide Quantum Electrodynamics with Superconducting Qubits
… artificial atoms, typically operated as qubits, to one-dimensional transmission lines. We first demonstrate that superconducting qubits in a waveguide QED system can be used as high-quality quantum emitters. We then leverage the quantum interference between the simultaneous emission from …
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Waveguide quantum electrodynamics with superconducting qubits
… parameter regime of strong interactions between qubits and open waveguides. In these setups, known as waveguide quantum electrodynamics (WQED), superconducting qubits interact with a continuum of propagating photonic modes. In this thesis, we will explore the physics of WQED devices that consist …
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Majorana qubits in non-Abelian topological superconductors
… and how they affect the stability of topological qubits and gates built from the Majorana quasiparticles. The main decoherence effects are the tunneling splitting of the topological degeneracy, thermal excitations and superconducting fluctuations which are not treated in the usual BCS mean-field …
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Simulation algorithms, Floquet phenomena and superconducting qubits
… from physical properties of superconducting qubits to computational properties of algorithms for quantum simulation. In the introduction, we begin by reviewing the circuit model of quantum computing. We then introduce circuit quantum electrodynamics (QED), the framework by which …
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Non-Gaussian noise spectroscopy with superconducting qubits
Most quantum control and quantum error-correction protocols assume that the noise causing decoherence is described by Gaussian statistics. However, the Gaussianity assumption breaks down when the quantum system is strongly coupled to a sparse environment or has a non-linear response to external …
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Design and Engineering of Protected Superconducting Qubits
… processors becomes increasingly promising as the qubits exhibit longer coherence times. To this end, realizing protected qubits, whose Hamiltonians are inherently resilient to both relaxation and dephasing, has attracted strong interest. In this thesis, we primarily explore the soft 0 − π qubit, a …
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Polarization Sensitive Imaging Techniques Using Quantum Entangled Qubits
… study imaging techniques using quantum entangled qubits. These techniques extract information about the quantum state of two entangled qubits and corelate the degree of entanglement to each pixel. Imaging information of the underlying structure or material is decoded using the reconstruction of …
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Decoherence and Dynamical Decoupling in Solid-State Spin Qubits
This dissertation is a study of the decoherence of a solid-state spin qubit, either that of a localized electron spin or a donor nucleus, caused by a nuclear spin bath relevant to semiconductor quantum computer architectures. In the presence of an external magnetic field and at low temperatures, …
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Quantum Simulation of Many-body Systems with Superconducting Qubits
… We use a 3×3 array of superconducting transmon qubits to study the dynamics of a particle under the tight-binding model, and probe quantum information propagation by measuring out-of-time-ordered correlators (OTOCs). Using a 4×4 qubit array, we probe entanglement across the energy spectrum of a …
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Magnetic flux measurement of superconducting qubits with Josephson inductors
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.
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Exploring Anisotropic Noise and Fast Gates with Superconducting Qubits
… coherence and control, utilizing superconducting qubits. Our first result is the characterization of superconducting qubit flux noise, a primary source of decoherence, under the influence of weak, in-plane magnetic fields. We reveal two trends which serve as a novel experimental benchmark for …
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Compensating sequences for robust quantum control of trapped-ion qubits
… requires precision control of the dynamics of qubits. Frequently accurate quantum control is impeded by systematic drifts and other errors. Compensating composite pulse sequences are a resource efficient technique for quantum error reduction. This work describes compensating sequences for …
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Super-resolution localization and readout of individual solid-state qubits
A central goal in quantum information science is to establish entanglement across multiple quantum memories in a manner that allows individual control and readout of each constituent qubit. In the area of solid state quantum optics, a leading system is the negatively charged nitrogen vacancy center …
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Implémentation d’une plateforme de caractérisation rapide pour les qubits de spin
… années. Parmi les différentes architectures, les qubits de spin sont prometteurs grâce à leur long temps de cohérence et leur compatibilité avec les méthodes de fabrication industrielle. Par contre, plusieurs défis restent à relever afin de mettre à l'échelle cette technologie. Par exemple, la …
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High-fidelity microwave control of single-atom spin qubits in silicon
… of the full operation of single-spin qubits in Si. Our qubits consist of the electron and nuclear spins of a single phosphorus atom, implanted in a Si substrate, and controlled by a gated nanostructure. We describe an experimental setup tailored to minimise electron temperature and …
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