BMETE15MF60

Course data
Course name: Quantum Computing Architectures
Neptun ID: BMETE15MF60
Responsible teacher: András Pályi
Department: Department of Theoretical Physics
Programme: Courses for Physicist MSc students
Course data sheet: BMETE15MF60
Requirements, Informations

Information

We will offer this course again in 2020 Fall semester.

Course information - 2018 Fall Semester

  •     Lecturers: András Pályi, Péter Makk
  •     Responsible lecturer: András Pályi
  •     Language: English
  •     Location: building H, room H601
  •     Time: Wednesdays, 12:15-13:45
  •     Schedule: first lecture: Sep 5; no lecture on Sep 12, Sep 26, Oct 10, and nov 14; last lecture: Dec 5.
  •     Neptun Code: BMETE15MF60
  •     Credits: 3
  •     Exam: Short written test + oral exam. Dates: Dec 17, Jan 7, Jan 14, Jan 21. Exams start at 8:00am.

Slides

  1. Quantum bits
  2. Control of quantum systems
  3. Qubits based on the electron spin
  4. Coherent control of electron spins
  5. Information loss mechanisms for electron spins
  6. Superconducting qubits: basic architectures
  7. Flux and charge qubits, cQED
  8. Qubit-qubit coupling
  9. State tomography
  10. Grover algorithm, quantum teleportation

Contents

  1. Quantum bits
    Qubits, dynamics, measurement, polarization vector, composite systems, logical gates, circuits, algorithms.
  2. Control of quantum systems.
    Hamiltonians, propagators, and quantum gates. Larmor precession, Rabi oscillations, dispersive resonator shift in the Jaynes-Cummings model, exchange interaction, virtual photon exchange.
  3. Qubits based on the electron spin.
    Quantum dots, energy scales. Interactions: Zeeman, spin-orbit, hyperfine, electron-phonon, electron-electron.
  4. Coherent control of electron spins.
    Single-qubit gates: magnetic resonance, electrically driven spin resonance. Two-qubit gates: sqrt-of-swap via exchange interaction, CPhase. Error mechanisms during qubit control.
  5. Information loss mechanisms for electron spins.
    Qubit relaxation due to spin-orbit interaction and phonons. Qubit dephasing due to nuclear spins. Decoherence due to charge noise. Hahn echo and Car-Purcell-Meibloom-Gill (CPMG) schemes for prolonging the decoherence time.
  6. Introduction to superconductivity.
    Basics of superconductivity. Josephson junctions. Current-phase and voltage-phase Josephson relations. Andreev reflection. Andreev Bound State picture of the current-phase Josephson relation.
  7. Josephson devices.
    Resistively and capacitively shunted junction (RCSJ) model, junction dynamics, switching voltages, macroscopic quantum tunnelling, Superconducting Quantum Interference Device (SQUID), Fraunhofer pattern, spatial distribution of the Josephson current, radiofrequency (RF) SQUID.
  8. Control and readout of single qubits.
    Quantization of RF circuits, phase and charge as conjugate variables. Different qubit architectures: flux, charge, phase. Single-qubit gates and readout.
  9. Information loss in superconducting qubits.
    Experiments on single qubits. Deceoherence in qubits, sweet spots. Transmon as a noise-resistant qubit architecture.
  10. Circuit quantum electrodynamics.
    Superconducting resonators and their interaction with a transmon qubit. Strong coupling in circuit quantum electrodynamics. Single-qubit gates and dispersive readout via the resonator.
  11. Entanglement in superconducting qubits.
    Two-qubit coupling mechanisms: capacitive, resonator-based. Two-qubit gates. State tomography, Bell inequalities.
  12. Multi-qubit devices.
    Realization of basic quantum algorithms. Error correction: repetition code, surface code.
  13. Overview of current research directions.
    Quantum simulation. Intermediate-scale quantum computers (Google, IBM, Intel, D-Wave).

 

Literature

  • T. Ihn: Semiconducting nanosctructures, Oxford University Press, 2010.
  • Y.V. Nazarov, Y.M. Blanter: Quantum Transport: Introduction to Nanoscience, Cambridge University Press, 2009.
  • Zwanenburg et al., Rev. Mod. Phys. 85, 961 (2013)
  • Nanofizika tudásbázis