Hybrid quantum system based on rare earth doped crystals
Hybrid quantum system based on rare earth doped crystals

Author: Probst, Sebastian

Publisher: KIT Scientific Publishing

Published: 2016-09-05

Total Pages: 156

ISBN-13: 373150345X

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Hybrid quantum circuits interfacing rare earth spin ensembles with microwave resonators are a promising approach for application as coherent quantum memory and frequency converter. In this thesis, hybrid circuits based on Er and Nd ions doped into Y?SiO? and YAlO? crystals are investigated by optical and on-chip microwave spectroscopy. Coherent strong coupling between the microwave resonator and spin ensemble as well as a multimode memory for weak coherent microwave pulses are demonstrated.

Hybrid Quantum Systems
Hybrid Quantum Systems

Author: Yoshiro Hirayama

Publisher: Springer Nature

Published: 2022-01-06

Total Pages: 352

ISBN-13: 9811666792

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This book presents state-of-the-art research on quantum hybridization, manipulation, and measurement in the context of hybrid quantum systems. It covers a broad range of experimental and theoretical topics relevant to quantum hybridization, manipulation, and measurement technologies, including a magnetic field sensor based on spin qubits in diamond NV centers, coherently coupled superconductor qubits, novel coherent couplings between electron and nuclear spin, photons and phonons, and coherent coupling of atoms and photons. Each topic is concisely described by an expert at the forefront of the field, helping readers quickly catch up on the latest advances in fundamental sciences and technologies of hybrid quantum systems, while also providing an essential overview.

Adding nonlinearity to an electromagnetic-magnonic quantum hybrid device
Adding nonlinearity to an electromagnetic-magnonic quantum hybrid device

Author: Pfirrmann, Marco

Publisher: KIT Scientific Publishing

Published: 2020-10-05

Total Pages: 136

ISBN-13: 3731510030

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In this book, hybrid systems based on yttrium-iron-garnet (YIG), three dimensional microwave cavity resonators, and superconducting transmon qubits, are investigated by continuous wave and pulsed microwave spectroscopy. Limitations to the magnetic linewidth in the quantum regime are identified and coherent exchange between a magnon and a superconducting qubit are demonstrated. Finally, a first step towards a strongly coupled hybrid system containing all three components is demonstrated.

Molecular Motor Based on Single Chiral Tripodal Molecules Studied with STM
Molecular Motor Based on Single Chiral Tripodal Molecules Studied with STM

Author: Skolaut, Julian

Publisher: KIT Scientific Publishing

Published: 2023-09-14

Total Pages: 164

ISBN-13: 3731512475

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This work presents a single molecular motor driven by the current in an STM. Its chiral functional group is supposed to perform a rotation in a preferred direction, proven by Binomial tests to be statistically significant. The rotation is proposedly driven by the chiral-induced spin selectivity effect (CISS). However, the studies of the rotation on the dependence on the lateral tip position, voltage and current indicate that he CISS is unlikely to cause the preferred rotation direction.

Elastic and Inelastic Scanning Tunneling Spectroscopy on Iron-Based Superconductors
Elastic and Inelastic Scanning Tunneling Spectroscopy on Iron-Based Superconductors

Author: Jandke, Jasmin Maria

Publisher: KIT Scientific Publishing

Published: 2019-05-02

Total Pages: 242

ISBN-13: 3731507471

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Within this work, the pairing mechanism of conventional (Pb) and unconventional superconductors (SrFe2(As1-xPx )2 , FeSe, FeSe/STO) was investigated experimentally by means of elastic and inelastic tunneling spectroscopy at temperatures down to 30 mK. The distinction between elastic and inelastic contributions to tunneling data was elaborated. The results help to identify conventional (phonon-mediated) and unconventional (e.g. spin-?uctuation mediated) superconductivity.

Quantum Sensing Experiments with Superconducting Qubits
Quantum Sensing Experiments with Superconducting Qubits

Author: Schneider, Andre

Publisher: KIT Scientific Publishing

Published: 2021-06-04

Total Pages: 170

ISBN-13: 3731510324

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Quantum sensing is a vast and emerging field enabling in-situ studies of quantum systems and hence the development of quantum hybrid systems. This work creates the fundament of direct superconducting-magnetic hybrid systems by developing a local microwave sensing scheme and studying the influence of a static magnetic field on a superconducting qubit. Finally, a proof-of-principle hybrid system is demonstrated, which opens the path towards superconducting-magnetic quantum circuits.

Quantum Tunneling of Josephson Vortices in High-Impedance Long Junctions
Quantum Tunneling of Josephson Vortices in High-Impedance Long Junctions

Author: Wildermuth, Matthias Micha

Publisher: KIT Scientific Publishing

Published: 2023-09-11

Total Pages: 160

ISBN-13: 373151303X

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In the last decades, superconducting devices have emerged as a promising platform for quantum technologies, including quantum sensing and quantum computing. Their key elements are Josephson junctions, which allow for coherent supercurrent tunneling between two weakly linked superconductors. If such a junction is extended in one direction to a long junction, the superconducting phase difference can vary in space and time and may allow for quantized phase windings that drive supercurrent vortices.

Local Probing of a Superconductor’s Quasiparticles and Bosonic Excitations with a Scanning Tunnelling Microscope
Local Probing of a Superconductor’s Quasiparticles and Bosonic Excitations with a Scanning Tunnelling Microscope

Author: Gozlinski, Thomas

Publisher: KIT Scientific Publishing

Published: 2023-03-24

Total Pages: 208

ISBN-13: 3731512793

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Complementary to scattering techniques, scanning tunnelling microscopy provides atomic-scale real space information about a material's electronic state of matter. State-of-the-art designs of a scanning tunnelling microscope (STM) allow measurements at millikelvin temperatures with unprecedented energy resolution. Therefore, this instrument excels in probing the superconducting state at low temperatures and especially its local quasiparticle excitations as well as bosonic degrees of freedom.

Light Emission from Single Self-decoupled Molecules in a Scanning Tunnelling Microscope
Light Emission from Single Self-decoupled Molecules in a Scanning Tunnelling Microscope

Author: Rai, Vibhuti Narayan

Publisher: KIT Scientific Publishing

Published: 2022-10-04

Total Pages: 150

ISBN-13: 3731512017

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In this work, a clear pathway is presented to achieve well-defined electronically decoupled chromophores from metallic leads without requiring additional insulating layers. To study such self-decoupled molecules, STM equipped with an efficient light detection setup has been used. Results show that the chromophores mounted on tripodal molecular platforms adsorbed on a gold surface present well-defined and efficient electroluminescence down to the single-molecule level.

Local Investigation of Single Magnetic Molecules with Scanning Tunneling Microscopy
Local Investigation of Single Magnetic Molecules with Scanning Tunneling Microscopy

Author: Chen, Jinjie

Publisher: KIT Scientific Publishing

Published: 2019-01-18

Total Pages: 146

ISBN-13: 3731508192

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We worked on different magnetic molecules containing 3d and 4f magnetic centers. Their growth on metallic surfaces, topographies, spin states, magnetic properties and electron transport were locally investigated by using scanning tunneling microscopy (STM) at temperatures down to 30mK. The main achievement of this dissertation reveals the abrupt switching of crystal fields during formation of molecular contacts.