Certain quantum many-body physics problems, such as the transverse field Ising model are intractable on a classical computer, meaning that as the number of particles grows, or spins, the amount of memory and computational time required to solve the problem exactly increases faster than a polynomial behavior.However, quantum simu-I would like to thank my advisor, Professor James Freericks, for all the help and guidance he provided me throughout my time at Georgetown University.I know I am not the easiest person to work with and I imagine at times it was frustrating.I have learned a significant amount about quantum computing with trapped ions, unfortunately one thing that I still need to work on is my atrocious writing.Beyond the opportunity of doing research with Professor Freericks, he has also given me the opportunity to mentor many undergraduates.I have enjoyed every minute of my work.It has been a privilege and an honor working with you.Of course, I would not have gotten as far as I did without the help from my fellow classmates.Thanks to my classmates: Alan Pasha Tabatabai, Khadijeh "Sona" Najafi, and Oliver Albertini, who got me through the first and second year courses.I passed solid state II and the comprehensive exam because of these three classmates.As for the older graduate students, thanks to Jesús Cruz-Rojas who helped me stay motivated during my research blues stage.Although, we were quite prone to discussing random algorithms and other projects that did not have anything to do with our research.
Certain quantum many-body physics problems, such as the transverse field Ising model are intractable on a classical computer, meaning that as the number of particles grows, or spins, the amount of memory and computational time required to solve the problem exactly increases faster than a polynomial behavior.However, quantum simu-I would like to thank my advisor, Professor James Freericks, for all the help and guidance he provided me throughout my time at Georgetown University.I know I am not the easiest person to work with and I imagine at times it was frustrating.I have learned a significant amount about quantum computing with trapped ions, unfortunately one thing that I still need to work on is my atrocious writing.Beyond the opportunity of doing research with Professor Freericks, he has also given me the opportunity to mentor many undergraduates.I have enjoyed every minute of my work.It has been a privilege and an honor working with you.Of course, I would not have gotten as far as I did without the help from my fellow classmates.Thanks to my classmates: Alan Pasha Tabatabai, Khadijeh "Sona" Najafi, and Oliver Albertini, who got me through the first and second year courses.I passed solid state II and the comprehensive exam because of these three classmates.As for the older graduate students, thanks to Jesús Cruz-Rojas who helped me stay motivated during my research blues stage.Although, we were quite prone to discussing random algorithms and other projects that did not have anything to do with our research.
Las simulaciones cuanticas consisten en la reproduccion intencional de una dinamica cuantica en otro sistema cuantico que es tipicamente mas controlable.Mas alla de su naturaleza interdisciplinar, las simulaciones cuanticas prometen revolucionar las tecnologias de la computacion y resolver problemas computacionalmete intratables con minimos requerimientos experimentales.De esta manera, se espera que en un futuro cercano las simulaciones cuanticas resuelvan problemas complejos, exponencialmente mas rapido que los ordenadores clasicos, volviendose una herramienta indispensable para cientificos e ingenieros.En esta tesis comenzamos con la simulacion cuantica de modelos de mecanica cuantica relativista, y mas tarde profundizamos en la implementacion de modelos de teoria cuantica de campos y modelos emergentes de materia condensada en iones atrapados. Ademas , proponemos un marco matematico que permite a las simulaciones cuanticas generar operaciones no-fisicas, como conjugacion de carga o inversion temporal durante la dinamica simulada. Esto contribuye a incrementar la versatilidad de las simulaciones cuanticas y tambien estudiar sus limites en relacion con conceptos como simulatabilidad, computabilidad, y indecibilidad.
The development of quantum electrodynamics (QED), which studies the light-matter interaction in quantum level, has been accompanied by the enhancement of the coupling strength g between an atom (matter) and an electromagnetic (EM) field (light).With the introduction of a cavity, forming a cavity QED system, the coupling strength reached weak coupling (WC) and strong coupling (SC) regime.These regimes are defined by the system dissipations, the atom decay rate γ and the cavity decay rate κ, where g ≪ γ, κ for the WC regime and g ≫ γ, κ for the SC regime.Especially for the SC regime, the energy exchange between the atom and the EM field can happen repeatedly before the system losses the energy.This physical property enables quantum state manipulation in First and foremost, I would like to express my sincere appreciation to my principal supervisor, Takao Aoki, for his advice and support during my PhD studies.He is the first person who welcomed me to the field of cavity quantum electrodynamics at the end my third-year as an undergraduate student.Then, when I proposed to go to NICT and study about circuit QED and USC/DSC regimes, he agreed and quickly worked on the joined research contract, which yield the contents of this thesis.I still remember his words, "the Hamiltonian is the same anyway", which he said after agreeing my proposal.I also would like to thank him to allow me to the Leading Graduate Program in Science and Engineering and Power Energy Professional WISE Program.These programs require extra work for some unique curriculums, such as Lab.Rotations, internship and studying abroad.He has been supportive and flexible all the time and gave me full room to what I needed to do.All these works could not be done without support and guidance.Next, I would like to thank the members of Macroscopic Quantum Physics Project, National Institute of Information and Communication Technologies (NICT).I greatly appreciate Kouichi Semba, the leader of the project, letting me join the team and supported my PhD studies.He recommended me to Prof. William D. Oliver at MIT which made my visiting stay at EQuS at MIT become true.I also want to thank you him for applying for the fund by CREST which greatly helped me financially for a period of working at NICT.His advices and supports were not only very helpful for the works but also enriched my life.Fumiki Yoshihara was my mentor all the time during these works.He told me how to design and analyze the circuits, prepare the samples and operate the systems for experiments.He always answered me when I face problems and help me solve them, even they are easy ones.It has to be pointed out that he gave me the idea coupling the qubit to multiple modes in the resonator.This research topic has been tough due to its complicity, yet also been fun to mess around.I also appreciate he invited me to the soccer games during the lunch breaks.The cryostat which I used to cool the circuits was mostly prepared by Tomoko Fuse.She also told me how to prepare the cryostat and manage the cables inside it.Her advices and comments on my works were always greatly helpful.As a theorist Sahel Ashhab supported my works from the basic ideas.His advices helped me a lot to understand what is happening in the systems.He also helped me analyze the multimode circuit QED system by carefully deriving the expressions.I would like to thank the of the group, Sunmi Kim, with the discussions over chip designs and preparation of the Lab.At the end, I thank Akiko Hoshi for dealing all the paper works and Takashi Nakayama for helping me with the coding and equipment preparation.Thirdly, I would like to thank Shiro Saito and Kosuke Kakuyanagi from Superconducting Quantum Circuits Research Group at NTT Basic Research Laboratories.As the co-authors, they fabricated the samples with maximum care.I also appreciate the discussions about the experimental results where they always gave helpful advices and suggestions.I would like to thank all the members for the discussions during my iii internship at the same group.I especially thank Shiro Saito and Satoru Toida, the mentor during the internship, to let me join the group and conduct experiments.It was a great experience to work with the top-level researchers around the globe.I also would like to thank my two supervisors of the two Lab.Rotations, Kazuya Yuasa and Hiroshi Kawarada, for giving me the opportunity to join them.Although they were for a short period of time, the experiences broaden my interests towards science and engineering and will be surely valuable for me.I am deeply grateful to my supervisor of Engineering Quantum Systems group, William D. Oliver, for making me joining with he and the other Laboratory members and hosted my stay.I also appreciate the discussions and works with Roni Winik, who patiently explained his research and brought me in with his research topic.I spent a great time discussing and chatting with the group members and enjoyed working with them.I also want to thank William D. Oliver who applied a
Despite knowing the fundamental equations in most of the physics research areas, still there is an unceasing need for theoretical method development, thanks to the more and more challenging problems addressed by the research community.The investigation of post-silicon, non-classical information processing is one of the new and rapidly developing areas that requires tremendous amount of theoretical support, new understanding, and accurate theoretical predictions.My thesis focuses on theoretical method development for solid-state quantum information processing, mainly in the field of point defect quantum bits (qubits) in silicon carbide (SiC) and diamond.Due to recent experimental breakthroughs in this field, there are diverse theoretical problems, ranging from functional development for accurate first principles description of point defects, through complete theoretical characterization of qubits, to the modeling and simulation of actual quantum information protocols, that are needed to be addressed.The included articles of this thesis cover the development of (i) hybrid-DFT+V w approach for the first principles description of mixed correlated and uncorrelated systems, (ii) zero-field-splitting tensor calculation for solid-state quantum bit characterization, (iii) a comprehensive model for dynamic nuclear spin polarization of solid-state qubits in semiconductors, and (iv) group theoretical description of qubits and novel two-dimensional materials for topologically protected states.v vi First of all, I would like to thank my main supervisor, Prof. Igor Abrikosov, and my co-supervisors, Prof. Adam Gali and Prof. Erik Janzén, for their great guidance and helpfulness over the years.I appreciate and thank the numerous advice, the valuable discussions and the inspiring ideas.I am particularly grateful to all of them for providing and maintaining an unusual working agreement through which I can experience and learn much more than I could imagine before.Furthermore, I am thankful to Prof. Adam Gali for launching me on my career, helping from the beginning, and for involving me in several collaborations as well as to Prof. Igor Abrikosov for showing me numerous theoretical techniques, guiding me towards method development studies, and for supporting during my PhD studies.I would like to thank all of the members of our Swedish and Hungarian groups for creating a friendly and helpful atmosphere and for always being open for discussions.I am also very grateful to all of my collaborators, particularly from
My time at Michigan has tremendous impacts on me, and for this I would like to thank many. My advisor, Professor Massoud Kaviany, led me into the exciting area of heat transfer physics, and encouraged me to take risks to explore new topics. I was allowed sufficient freedom to decide where the project should direct, while I could still benefit a lot from his insight and expertise. I am grateful to him for training me in every aspect to become a scholar. My committee member, Professor Stephen Rand, taught me a great deal when I was a newcomer to optics, and offered to meet with me many times all through my Ph.D. study, to discuss questions in my research. The other members of my committee, Professors John Kieffer, and David Reis, have provided support during the dissertation process. Professors Mahta Moghaddam, Gerard Mourou, Stephen Rand, David Reis, Duncan Steel, and James Wells taught courses that were very helpful to me for learning optics, quantum mechanics, and condensed matter physics. I would also like to thank the valuable discussions or