Experiments on Two-resonator Circuit Quantum Electrodynamics

Experiments on Two-resonator Circuit Quantum Electrodynamics PDF Author: Elisabeth Christiane Maria Hoffmann
Publisher:
ISBN:
Category :
Languages : en
Pages : 119

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Experiments on Two-resonator Circuit Quantum Electrodynamics

Experiments on Two-resonator Circuit Quantum Electrodynamics PDF Author: Elisabeth Christiane Maria Hoffmann
Publisher:
ISBN:
Category :
Languages : en
Pages : 119

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Book Description


Multiqubit experiments in 3D circuit quantum electrodynamics

Multiqubit experiments in 3D circuit quantum electrodynamics PDF Author: Jacob Blumoff
Publisher: Lulu.com
ISBN: 1387178563
Category : Science
Languages : en
Pages : 242

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Book Description
This thesis describes experimental work done in the field of quantum computing with three-dimensional circuit quantum electrodynamics devices.

Circuit Quantum Electrodynamics with Flux Qubits

Circuit Quantum Electrodynamics with Flux Qubits PDF Author: Jean-Luc François-Xavier Orgiazzi
Publisher:
ISBN:
Category :
Languages : en
Pages :

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This thesis presents circuit quantum electrodynamic (cQED) experiments done with artificial atoms coupled to a high quality factor superconducting microwave resonator. This work discusses the theoretical framework, design, fabrication, implementation and characterization of a multi-qubit system using superconducting persistent current qubits, often referred as flux qubits. We developed a new type of cryogenic aid for fast turnaround microwave experiments. The minimum turnaround time to perform microwave experiments in dilution refrigerators is typically a few days, as required by cooling down and warming up the entire refrigerator. The cryogenic microwave payload and wiring needed for each qubit and resonator add a significant heat load to the system which typically only has a few μW s of cooling power at millikelvin temperatures. We present a new experimental approach we developed in which a suitable sample holder is attached to a cold-insertable probe and brought in contact with transmission lines permanently mounted inside the cryostat. The total turnaround time is reduced to 8 hours if the target temperature is 80 mK. This new measurement method increased our ability to successfully identify good devices with fast design-characterization iterations, while allowing months-long measurements at 30 mK. Our device architecture uses several qubits, each of which is controlled via on-chip fast flux bias lines. Readout of the qubit's quantum state is performed by homodyne detection of the resonator field at large driving power. We observe long coherence times at the optimal bias point of the flux qubits and present decoherence measurements around this optimal point, where the flux qubits couple mostly to magnetic flux noise. Dynamical decoupling techniques employing fast microwave pulses are used to protect the qubit's coherence and allow calculating the magnetic flux noise power spectral density of the qubit's environment. Photon-mediated interaction between distant qubits in the resonator allows the implementation of a two-qubit controlled-NOT gate using the selective darkening technique. This multi-qubit superconducting design is an interesting platform to study the decoherence properties of flux qubits, the properties of strong interaction of electromagnetic radiation with macroscopic quantum systems. These results demonstrate the potential of cQED as a platform for fundamental investigations of decoherence and quantum dynamics of flux qubits.

Fluctuating Nonlinear Oscillators

Fluctuating Nonlinear Oscillators PDF Author: Mark Dykman
Publisher: Oxford University Press
ISBN: 019969138X
Category : Mathematics
Languages : en
Pages : 446

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Book Description
The book provides a unifying insight into a broad range of phenomena displayed by vibrational systems of current interest. The chapters complement each other to give an account of the major fundamental results and applications in quantum information, condensed matter physics, and engineering.

Decoherence and Time-Resolved Readout in Superconducting Quantum Circuits (Dekohärenz und Zeitaufgelösste Quantenmessung in Supraleitenden Schaltkreisen)

Decoherence and Time-Resolved Readout in Superconducting Quantum Circuits (Dekohärenz und Zeitaufgelösste Quantenmessung in Supraleitenden Schaltkreisen) PDF Author: Georg M. Reuther
Publisher: Logos Verlag Berlin GmbH
ISBN: 3832528466
Category : Computers
Languages : en
Pages : 158

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Book Description
Superconducting quantum circuits are promising candidates for solid-state based quantum computation. However, minimizing dissipation caused by external noise sources remains a tough challenge. Here, we present an analytic dissipative theory for a complex circuit of two resonators coupled via a flux qubit. In this 'quantum switch', the qubit acts as a tunable coupler between the resonators, which enables switching their interaction on and off. A natural application of this setup is to create entangled two-resonator states. However, it turns out that, even if the qubit has no dynamics, qubit dissipation affects the resonators to a considerable degree. For successful quantum information processing, it is desirable to demonstrate the coherence of qubit time evolution in single-shot experiments without too much backaction on the qubit. In the second part of this thesis, we present a novel scheme for a time-resolved single-run measurement of coherent qubit dynamics. For a charge qubit probed by a weak high-frequency signal, we find that the reflected outgoing signal possesses a time-dependent phase shift that is proportional to a qubit observable. A similar approach is presented for a flux qubit coupled to a resonantly driven high-frequency oscillator, which serves as a meter device for monitoring the time-resolved qubit dynamics.

A V-shape Superconducting Artificial Atom for Circuit Quantum Electrodynamics

A V-shape Superconducting Artificial Atom for Circuit Quantum Electrodynamics PDF Author: Etienne Dumur
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
This thesis focuses on the experimental realisation of an artificial atom with a V-shape energy level diagram.Inspired by trapped-ion experiments, we theoretically predict an ultra fast and high fidelity quantum nondestructive readout of qubit state by using the V-shape artificial atom in a circuit quantum electrodynamicsarchitecture.To realise this experiment, we have developed an experimental setup to perform transmission measurementsof our superconducting quantum circuits by heterodyne technique at very low temperatures (30mK) and verylow signal amplitude (fW). We also implemented a hardware and software environment enabling multi-tonespectroscopies and time-resolved measurements in order to control the quantum state of the artificial atomand the coherent field in the resonator. In addition, in order to optimise the experiment circuits we havecharacterised quarterwave microwave resonators made from aluminium and epitaxial rhenium thin films.The original quantum device is fabricated by two inductively coupled transmons. When the couplinginductance is of the order of the Josephson inductance, we observe “in-phase” and “out-of-phase” oscillatingmodes of the superconducting phase across the junctions. The energy spectrum of the system, measured bytwo-tone spectroscopy, is magnetic flux dependent. It is precisely described by our theoretical model leadingto an accurate determination of the circuit parameters. Because of their anharmonicity, in the low-energylimit, the two modes can be considered as two-level systems called qubits. At zero magnetic field, it hasbeen observed that the two qubits become coupled only by a cross-anharmonicity. This has been revealed,through three-tone spectroscopy, by a conditional frequency shift as large as 115MHz of one qubit transitiondepending on the other qubit state. All these experimental results demonstrate a V-shape energy diagram forour artificial atom which paves the way to an original and high performance read-out.

Principles and Methods of Quantum Information Technologies

Principles and Methods of Quantum Information Technologies PDF Author: Yoshihisa Yamamoto
Publisher: Springer
ISBN: 4431557563
Category : Computers
Languages : en
Pages : 615

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Book Description
This book presents the research and development-related results of the “FIRST” Quantum Information Processing Project, which was conducted from 2010 to 2014 with the support of the Council for Science, Technology and Innovation of the Cabinet Office of the Government of Japan. The project supported 33 research groups and explored five areas: quantum communication, quantum metrology and sensing, coherent computing, quantum simulation, and quantum computing. The book is divided into seven main sections. Parts I through V, which consist of twenty chapters, focus on the system and architectural aspects of quantum information technologies, while Parts VI and VII, which consist of eight chapters, discuss the superconducting quantum circuit, semiconductor spin and molecular spin technologies. Readers will be introduced to new quantum computing schemes such as quantum annealing machines and coherent Ising machines, which have now arisen as alternatives to standard quantum computers and are designed to successfully address NP-hard/NP-complete combinatorial optimization problems, which are ubiquitous and relevant in our modern life. The book offers a balanced mix of theory-based and experimentation-based chapters written by leading researchers. Extensive information is provided on Quantum simulation, which focuses on the implementation of various many-body Hamiltonians in a well-controlled physical system, Quantum key distribution, Quantum repeaters and quantum teleportation, which are indispensable technologies for building quantum networks with various advanced applications and require far more sophisticated experimental techniques to implement.

Experiments on Flux Qubits with Pi-shifters

Experiments on Flux Qubits with Pi-shifters PDF Author: Alexey Feofanov
Publisher: KIT Scientific Publishing
ISBN: 3866446446
Category : Science
Languages : en
Pages : 126

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Book Description
The results of the research re-ported in this work show that tunable gap flux qubits have a potential for building quantum registers. Cavities coupled to flux qubits can be used for in-formation storage and transfer between qubits. SFS π-shifters provide a simple approach to bias multi-qubit circuits. A possibility to change the qubit resonance frequency while preserving qubit coherence enables implementation of switchable coupling between qubits and cavities.

Fluctuating Nonlinear Oscillators

Fluctuating Nonlinear Oscillators PDF Author: Mark Dykman
Publisher: OUP Oxford
ISBN: 0191637548
Category : Science
Languages : en
Pages : 432

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Book Description
The book provides a unifying insight into fluctuation phenomena in a broad variety of vibrational systems of current interest. It consists of individual chapters written by leading experts in the field. The chapters are self-contained and complement each other. The ongoing rapid development of well-characterized mesoscopic vibrational systems has made it possible to address fundamental physics problems and to explore new approaches to quantum and classical measurements, with applications to quantum information, condensed matter physics, and engineering. The book gives an account of major results in this direction. The topics include dynamics and quantum control of microcavity modes coupled to qubits, measurements with bifurcation-based amplifiers and new types of such amplifiers; switching rate scaling and new quantum mechanisms of metastable decay; wave mixing and parametric excitation in the quantum regime; collective phenomena and the interaction-induced discrete time symmetry breaking; and back-action and shot noise in electron-vibrational systems.

Towards a Spin-Ensemble Quantum Memory for Superconducting Qubits

Towards a Spin-Ensemble Quantum Memory for Superconducting Qubits PDF Author: Cécile Grèzes
Publisher: Springer
ISBN: 3319215728
Category : Computers
Languages : en
Pages : 240

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Book Description
This work describes theoretical and experimental advances towards the realization of a hybrid quantum processor in which the collective degrees of freedom of an ensemble of spins in a crystal are used as a multi-qubit register for superconducting qubits. A memory protocol made of write, read and reset operations is first presented, followed by the demonstration of building blocks of its implementation with NV center spins in diamond. Qubit states are written by resonant absorption of a microwave photon in the spin ensemble and read out of the memory on-demand by applying Hahn echo refocusing techniques to the spins. The reset step is implemented in between two successive write-read sequences using optical repumping of the spins.