Module PHYS4121: ATOMS, LASERS AND QUBITS

Department: Physics

PHYS4121: ATOMS, LASERS AND QUBITS

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

• 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.

• 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.

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.

Teaching Methods and Learning Hours

Summative Assessment

Formative Assessment:

Problem exercises and self-assessment, workshops and problems solved therein.

■ Attendance at all activities marked with this symbol will be monitored. Students who fail to attend these activities, or to complete the summative or formative assessment specified above, will be subject to the procedures defined in the University's General Regulation V, and may be required to leave the University