# LIGHT AND MATTER - 2024/5

Module code: PHY3043

## Module Overview

The module is about quantum optics, which is the way that quanta of light interact with quantum objects. In Schrödinger’s famous cat paradox the animal was both alive and dead at the same time, but the thought experiment itself was pretty boring – just set up the cat, in a box, with some poison, a detector, and some radio-active substance, and let nature take its course. If you look in the box and repeat with many cats, sometimes they’re alive and sometimes dead, with a simple probability distribution determined by how long you wait. Quantum optics adds control – want the cat a bit more alive than dead? Want it completely dead? Want it to spring back to rude health? Just dial in the appropriate laser pulses and your ghostly quantum object (probably not a cat) will obey your command, just so long as you aren’t tempted to look at it. What useful things can you do with these ideas? Magnetic Resonance Imaging is one of the very few commercially available technologies that uses quantum superpositions, other than some fairly simple, but uncrackable, quantum encryption key transmission systems. But the future looks really bright, and possibly most excitingly, Quantum Computers will also take advantage of entanglement. In this effect, you can measure one bit of the entangled system and instantly find stuff out about others, no matter how far away they are. Even more amazing, you can fiddle around with some of the bits of the system and that has an instant effect on the others, even though they could be miles away and you don't touch them. Some detractors point out that there are not many quantum programs that have been shown to be better than classical computers, which are already doing pretty well thank you very much, but of course one of the problems is that so few people understand quantum computing enough to write them. After all, the hardware doesn't really exist yet! It’s just a symptom of an exploding subject in its infancy, and this module will even give you the tools to take part.

### Module provider

Mathematics & Physics

### Module Leader

MURDIN Benedict (Maths & Phys)

### Number of Credits: 15

### ECTS Credits: 7.5

### Framework: FHEQ Level 6

### Module cap (Maximum number of students): N/A

## Overall student workload

Independent Learning Hours: 66

Lecture Hours: 6

Seminar Hours: 5

Tutorial Hours: 8

Laboratory Hours: 3

Guided Learning: 51

Captured Content: 11

## Module Availability

Semester 1

## Prerequisites / Co-requisites

The module will assume prior knowledge equivalent to the following modules. If you have not taken these modules you should consult the module descriptors Level HE1 (FHEQ Level 4) Mathematical And Computational Physics PHY1038; Atoms And Quanta PHY1040 Level HE2 (FHEQ Level 5) From Atoms to Lasers PHY2062; Energy and Entropy PHY2063; Electromagnetic Waves PHY2065; Electromagnetism, Scalar and Vector Fields PHY2064; Quantum Physics PHY2069

## Module content

**Atoms: **The gas of classical oscillators and Rayleigh scattering. The Bohr model and its failures. Formalism of wave mechanics, Dirac notation. Spherical harmonics and the hydrogenic atom [without proof]. Wavefunction superpositions and observation.

**Spins: **A spins in a magnetic field. Matrix quantum mechanics: a pair of interacting spins (spin-orbit (fine) and spin-nuclear (hyperfine) interactions). Static field perturbations: the hydrogenic atom in a magnetic field. The Bloch sphere.

**Quantum matter and classical light waves: **The two-level atom: the Time-Dependent Schrödinger equation. Rotating Frames and the Rotating Wave Approximation. Rabi oscillations. Optical Bloch equations.

**Atomic Clocks and NMR/ESR: **Ramsey interference. Atomic clocks. Hahn spin echo. Pulsed Nuclear Magnetic Resonance (NMR)/Electron Spin Resonance (ESR). Photon echoes.

**Advanced quantum optics: **Dressed states, electromagnetically induced transparency, Autler-Townes effect and Mollow triplets. Optical cavities, atom-cavity coupling, weak and strong coupling and slow light. Two photon absorption and non-linear processes.

**Coherent and incoherent light: **Coherent and incoherent waves. Fourier Transforms. Michelson interferometer and coherence time. Fermi’s Golden Rule for discrete to continuum transitions. Statistical FGR for discrete to discrete transitions.

**Photons: **Classical intensity interferometers and first order correlations. Michelson stellar interferometer. Hanbury Brown–Twiss experiments and second order correlations. Coherent laser light and Poissonian photon statistics. Chaotic light and super-Poissonian (bunched) photon statistics. Sub-Poissonian (antibunching) photon statistics. The quantum HBT experiment, single-photon sources. Hong-Ou Mandel effect.

**Quantum cryptography and entanglement: **Quantum Cryptography. The BB84 quantum key distribution protocol. Quantum random number generation. Entanglement. Einstein Podolsky-Rosen paradox. Bell inequality.

**Quantum computing: **Quantum bits, quantum parallelism, quantum logic gates (NOT, CNOT etc). Quantum computer algorithms: the quantum Fourier Transform and Deutsch’s algorithm.

**Practical quantum technologies: **Qubit implementations: spins in semiconductors; trapped ions; superconducting resonators; flying qubits. Other quantum technologies: quantum sensors, quantum simulators.

## Assessment pattern

Assessment type | Unit of assessment | Weighting |
---|---|---|

Online Scheduled Summative Class Test | SURREYLEARN QUIZZES | 10 |

Coursework | COURSEWORK | 30 |

Examination | EXAM (2 hours) | 60 |

## Alternative Assessment

N/A

## Assessment Strategy

The __assessment strategy__ is designed to provide students with the opportunity to demonstrate

- analytical ability by solution of unseen problems in both coursework and exam
- subject knowledge by recall of both “textbook” theory and important research articles in the exam
- practical skill by solving an advanced problem in quantum optics either by completion of a laboratory or writing computer programs (depending on availability)
- ability to generalize textbook theory by open-ended research component in the coursework

Thus, the

__summative assessment__for this module consists of:

- an exam
- coursework, which will take about 40 hours of effort
- periodic on-line quizzes

__Formative assessment and feedback__

- periodic on-line practice quizzes
- Students will receive verbal feedback on progress with problems in tutorials and model solutions to the tutorial questions, and can participate in on-line discussion boards. Coursework is submitted in parts so that feedback on the first part can inform the second part etc.

## Module aims

- This module aims to: provide an understanding of the fundamentals, links and recent developments in atomic physics and quantum optics, with particular reference to practical and future Quantum Technologies such as quantum communications and quantum computing.

## Learning outcomes

Attributes Developed | ||

1 | Compare and contrast the behaviour of classical oscillators in classical waves with that of quantum oscillators interacting with photons | KC |

2 | Apply the time-dependent Schrödinger equation to a two level atom to produce superpositions and their evolution | KC |

3 | Explain the causes of quantum optical phenomena such as photon echoes | K |

4 | Relate quantum optical principles to real-life applications using photon echoes such as magnetic resonance imaging | KC |

5 | Theorize or generalize in unseen situations where quantum optics concepts apply | C |

Attributes Developed

**C** - Cognitive/analytical

**K** - Subject knowledge

**T** - Transferable skills

**P** - Professional/Practical skills

## Methods of Teaching / Learning

The __learning and teaching strategy__ is designed to provide:

- a comprehensive theoretical treatment for the subject knowledge
- practice in problem solving for the cognitive skills

The

__learning and teaching methods__include:

- Lectures: backed up with guided study and including captured content to stimulate uptake of subject knowledge
- Seminars: discussion forums of the key concepts including “classic” research articles and reviews describing applications of theory
- Tutorials: demonstration of solutions to key problems after students have attempted them for formative feedback
- Laboratories: practical skills provision with a choice of an advanced experiment (depending on equipment availability and demand) or computational laboratory contributing to coursework with a combination of lecturer contact and guided study
- Independent learning: problem sheets, reading lists and coursework (mentioned above)
- Guided Learning: periodic on line quizzes (formative and summative) for reinforcement of basic knowledge and skills; Captured content (mentioned above/below); guided computational or experimental laboratories (mentioned above); peer learning and teaching with structured Surrey-Learn hosted discussion boards.
- Captured Content: Recorded lectures to support the live lectures (mentioned above).

Indicated Lecture Hours (which may also include seminars, tutorials, workshops and other contact time) are approximate and may include in-class tests where one or more of these are an assessment on the module. In-class tests are scheduled/organised separately to taught content and will be published on to student personal timetables, where they apply to taken modules, as soon as they are finalised by central administration. This will usually be after the initial publication of the teaching timetable for the relevant semester.

## Reading list

https://readinglists.surrey.ac.uk

Upon accessing the reading list, please search for the module using the module code: **PHY3043**

Please note that the information detailed within this record is accurate at the time of publishing and may be subject to change. This record contains information for the most up to date version of the programme / module for the 2024/5 academic year.