Quantum Optics for Qubits

Course Aim

This course aims to deepen understanding of the working principles of quantum technologies for students who are or will be working on applied quantum physics.

Course Description

This course introduces basic notions of quantum optics and prepares a theoretical foundation that facilitates understanding the working principles of modern quantum devices, such as linear optical quantum computers, ion traps, superconducting circuits etc. In many cases physical systems used in quantum technology applications can be described by simple quantum physics of spins (two level systems) and harmonic oscillators. We start from basic algebras of a, a^dagger and Pauli, and then move on to topics such as coherent states, squeezed states, (anti-)bunching, photon statistics, Rabi oscillation, Bloch sphere, Ramsey interference, cavity QED, master equations, quantum input-output relation, two-qubit entangling gate, ion traps, Josephson junctions, circuit QED.

Course Contents

1. Basic algebra: bras and kets
Quantized EM field
Entanglement
2. Quantum harmonic oscillator: Fock states, Coherent states, squeezed states
3. Beam splitter and interferometer
Photon statistics: bunching and anti-bunching
4. Two-level systems interacting with classical fields
Rabi oscillation
5. Two-level systems interacting with quantum fields
Cavity QED
6. Open quantum systems
Master equation
Spontaneous emission
Decoherence
Ramsey interference
7. Quantum input-output relation
8. Qubit realization: photonics
9. Qubit realization: ion trap 1
10. Qubit realization: ion trap 2
11. Qubit realization: superconducting circuit 1
12. Qubit realization: superconducting circuit 2
13. Student self-working week for presentation
14. Presentation by students:
Reviewing selected papers

Assessment

•Problem sheet assignments 60%
•Final presentation about selected papers 40%

Prerequisites or Prior Knowledge

Undergrad-level quantum mechanics and linear algebra

Reference Books

1.“Measuring quantum state of light” by Ulf Leonhardt.
2.“An open systems approach to quantum optics” by H Carmichael.
3.“Methods in theoretical quantum optics” by Barrett and Radmore.