#### Prerequisites
* Foundations of Physics 3A (PHYS3621).
#### Corequisites
* None.
#### Excluded Combination of Modules
* None.
#### Aims
* This module is designed primarily for students studying Department of Physics or Natural Sciences degree programmes.
* It builds on the Level 3 module Foundations of Physics 3A (PHYS3621) and provides a working knowledge of lasers and the physics of quantum computation at an advanced level appropriate to Level 4 physics students.
#### Content
* The syllabus contains:
* Laser Physics: Definition of a laser. Atom-light interactions. Absorption, spontaneous and stimulated emission. Line broadening mechanisms and emission linewidth. Population inversion and gain. Laser oscillator: cavity basics and threshold; gain saturation and output power. Population inversion in 3 and 4-level systems. Laser pumping with case studies of specific laser systems. Cavity modes and cavity stability. Gaussian beams. Cavity effects: single frequency operation. Cavity effects: Q switching and mode locking. Laser spectroscopy and optical frequency combs. Case studies of laser applications.
* Quantum Information and Computing: Manipulation of qubits: Limits of classical computing. Feynman’s insight. Quantum mechanics revision. Projection operators. Pauli matrices. Single-qubit operations: Resonant field, the Rabi solution. The Bloch sphere. The Ramsey technique. Two-qubit states. Tensor products. Correlations. Entanglement. Bell states. Two-qubit gates. The CNOT gate. Physical Realizations: The DiVincenzo criteria. Controlling the centre-of mass motion of atoms – laser cooling. Controlling the internal states of atoms. Trapping and manipulating single atoms. Rydberg states. Decoherence. Case studies of contemporary Quantum Information Processing.
#### Learning Outcomes
Subject-specific Knowledge:
* Having studied this module students will be aware of the principles of lasers and be able to describe the operation, design features and uses of various laser systems.
* They will be familiar with the concept of the qubit and with the manipulation of qubits with electromagnetic fields, with many-qubit states, their correlation properties and the concept of entanglement, with quantum gates, quantum computing and the physical realization of these ideas.
Subject-specific Skills:
* In addition to the acquisition of subject knowledge, students will be able to apply knowledge of specialist topics in physics to the solution of advanced problems.
* They will know how to produce a well-structured solution, with clearly-explained reasoning and appropriate presentation.
Key Skills:
#### Modes of Teaching, Learning and Assessment and how these contribute to the learning outcomes of the module
* Teaching will be by lectures and workshops.
* The lectures provide the means to give a concise, focused presentation of the subject matter of the module.
* The lecture material will be explicitly linked to the contents of recommended textbooks for the module, thus making clear where students can begin private study.
* When appropriate, lectures will also be supported by the distribution of written material, or by information and relevant links online.
* Regular problem exercises and workshops will give students the chance to develop their theoretical understanding and problem solving skills.
* Students will be able to obtain further help in their studies by approaching their lecturers, either after lectures or at mutually convenient times.
* Student performance will be summatively assessed through an open-book examination and formatively assessed through problem exercises.
* The open-book examination will provide the means for students to demonstrate the acquisition of subject knowledge and the development of their problem-solving skills.
* The problem exercises provide opportunities for feedback, for students to gauge their progress and for staff to monitor progress throughout the duration of the module.
More information at: https://apps.dur.ac.uk/faculty.handbook/2023/UG/module/PHYS4121