The course explores the structure, characteristics, non-idealities, and models of devices for Qbit implementation. The existing technologies, both mainstream and experimental will be detailed and the most important parameters will be analyzed in oder to clarify the relation between the technology and the device behavior . The module also analyzes circuits used to interface Qbits devices and their fundamental design paramenters. Discussions on behavior at cryogenic temperature and high frequencies will be a focus of the module as well.

The student will know the main characteristics, non-idealities and models of devices for the Qbit implementations for the existing technologies. The student will know how to describe and model the Qbit devices in order to simulate the behavior, to understand the possible expected performance, noise degradation, and the dependency of characterisitcs on technological parameters. The student will know the methods and tools associated to the real exploitation of current technological implementation of Qbits. The student will be able to describe, model and simulate the circuits to interface Qbit devices to standard technology, to evaluate the impact of possible design paramenters anche choices on the Qbit expected behavior. The student will have the ability to analyze the impact of operating conditions on Qbit devices and on standard technology circuits (e.g. temperature, noise, interference, process variations). The capability to analyze and design simple cryo-CMOS circuits will be also an expected knowledge.

Fundamental on the Josephson junction Fundamentals on superconductivity Resonators Technological processes for quantum bit implementation Basics on Quantum information processing Basics of digital and analog electronics Basics on solid-state devices and nanoscale phenomena

Study, model, design and characterization of single Qbit elements, their control and read-out. The main technologies currently existing or under study will be the objective, as (1.5 CFU): - Superconductive structures - Trapped ions structures - Nano Magnetic Resonance and molecules-based structures - Quantum Dot structures For some of the main type of Qbit realization the focus will be on the control and readout of the Qbit through (2 CFU): - magnetic resonance - RF reflectometry - Josephson Junctions - Electron Spin Resonance - Electric Dipole spin resonance - Analog to Digital Converters - Digital to Analog converters - Low Noise Amplifiers - ASIC/FPGA dedicated systems - Cryogenic control, Cryo-CMOS components Models of the Qbit will be derived considering the main parameters for each of the I/O elements used, facing attention to the non-idealities and actual impact of the hardware used on the Qbit effective performance. Relaxation time and maximum coherence time, associated with electronics non idealities (temperature, ADC/DAC, bit parallelism and delay/power trade off) (2.5 CFU) A design perspective will be adopted during the study and analysis to provide methods and tools to use the knowledge in realistic cases. In all the cases the structures will be simulated where possible and example of control and/or measurement circuits will be implemented in practical laboratories.

The course consists of theoretical lectures and an application part of exercises carried out in the laboratory with the aid of circuit simulator tools. The experimental exercises involve the development of an incremental model of a Qbit, including the surrounding electronics for its read-out. The number of exercises foreseen is 3 and are carried out in the laboratory by a group of 3/4 students. Each laboratory requires drafting a report which will contribute to the achievement of the final grade.

The course consists of theoretical lectures and an application part of exercises carried out in the laboratory with the aid of circuit simulator tools. The experimental exercises involve the development of an incremental model of a Qbit, including the surrounding electronics for its read-out. The number of exercises foreseen is 3 and are carried out in the laboratory by a group of 3/4 students. Each laboratory requires drafting a report which will contribute to the achievement of the final grade.

Slides used in the lessons are available as well as laboratory guide. Books suggested are: - Quantum Computing, from linear algebra to physical realization, M. Nakahara, T.Ohmi, CRC Press, Taylor and Francys Book - Principles of Superconductive Quantum Computers, D.D. Stancil, G.T. Bird, Wiley and Sons Inc. - Quantum information and quantum optics with superconducting circuits” by Juan José García Ripoll

Modalità di esame: Prova orale obbligatoria; Elaborato progettuale in gruppo;

Exam: Compulsory oral exam; Group project;

... The exam consists of two parts: E1 an oral exam and E2 the execution of the laboratory exercises with related reports. The part linked to the laboratories (E2) weighs 20% of the final evaluation, while the oral discussion (E1) weighs 80%. The oral exam will be based on two questions associate to both the theoretical criteria for Qbit implementation and the practical skills associate to circuit implementation. In the laboratory reports, the completeness and accuracy of the arguments, the organization and the conciseness of the report are evaluated.

Gli studenti e le studentesse con disabilità o con Disturbi Specifici di Apprendimento (DSA), oltre alla segnalazione tramite procedura informatizzata, sono invitati a comunicare anche direttamente al/la docente titolare dell'insegnamento, con un preavviso non inferiore ad una settimana dall'avvio della sessione d'esame, gli strumenti compensativi concordati con l'Unità Special Needs, al fine di permettere al/la docente la declinazione più idonea in riferimento alla specifica tipologia di esame.