Quantum Magnetism, Spin Waves, and Light (PW QMag)5 ECTS
(englische Bezeichnung: Quantum Magnetism, Spin Waves, and Light)
(Prüfungsordnungsmodul: Quantum Magnetism, Spin Waves, and Light)

Lehrveranstaltungen:

• • Quantum Magnetism, Spin Waves, and Light
    (Vorlesung, 2 SWS, Silvia Viola Kusminskiy et al., Mi, 14:00 - 16:00, SRTL (307))
  • Quantum Magnetism, Spin Waves, and Light (UE)
    (Übung, 1 SWS, Silvia Viola Kusminskiy et al., Mi, 16:00 - 17:00, SRTL (307))

Inhalt:

Both magnetic materials and light have always played a predominant role in the storage, processing, and communication of information, and continue to do so as we move into the realm of quantum technologies. In this course we review the basics of magnetism before embarking in more advanced subjects, which will give us the basic tools to go over a selection of topics of current research. Magnetism is intrinsically quantum mechanical in nature, and magnetic ordering can only be explained by use of quantum theory. We will go over the interactions and the resulting Hamiltonian that governs magnetic phenomena, and discuss its elementary excitations, denominated magnons. After that we will study magneto-optical effects and derive the classical Faraday effect. This will allows us to understand a topic of current research denominated Cavity Optomagnonics. If the time allows, we will study another modern topic which deals with the design of photonic and magnonic crystals at the nanoscale. Basic knowledge of quantum mechanics, electromagnetism, and solid state at the bachelor level will be assumed.

1) Review of magnetism

1.1) Ampere’s Law, magnetic moment and magnetization
1.2) Magnetic induction and susceptibility
1.3) Equations of motion
1.4) Paramagnetism, diamagnetism, (anti)ferromagnetism
1.5) Demagnetization fields, Gauss Law
1.6) Maxwell equations, magnetostatic approximation
1.7) Atomic origins of magnetism: Angular momentum quantization, Spin

2) Quantum magnetism

2.1) Weiss molecular fields and exchange interactions, magnetic ordering
2.2) Heisenberg Hamiltonian, Ising and XY models
2.3) Spin Operators, Holstein Primakoff
2.4) Spin waves and Magnons
2.5) Magnon dispersion, dipolar and exchange waves
2.6) Bounded and unbounded bodies
2.7) Magnon interactions, instabilities
2.8) Magnetic order in metals: itinerant vs. localized magnetism
2.9) Magnetic textures

3) Magneto - optical effects

3.1) Electromagnetic waves in dispersive media and zero loss condition
3.2) Gyrotropic media
3.3) Faraday and inverse Faraday effect
3.4) Ultrafast magnetization processes

4) Modern topics: Cavity Optomagnonics

4.1) Optical cavities
4.2) Optomagnonic Hamiltonian
4.3) Light-induced spin dynamics

5) Modern Topics: design at the nanoscale

5.1) Photonic crystals
5.2) Magnonic crystals
5.3) Optomechanical crystals

Lernziele und Kompetenzen:

Learning goals and competences:
Students

• explain the relevant topics of the lecture
  

• apply the methods to specific examples

Verwendbarkeit des Moduls / Einpassung in den Musterstudienplan:

1. Physik mit integriertem Doktorandenkolleg (Master of Science)
   (Po-Vers. 2018w | NatFak | Elitestudiengang Physik mit integriertem Doktorandenkolleg (Master of Science) | Gesamtkonto | Physics elective courses | Quantum Magnetism, Spin Waves, and Light)

Studien-/Prüfungsleistungen:

Quantum Magnetism, Spin Waves, and Light (Prüfungsnummer: 909727)

(englischer Titel: Quantum Magnetism, Spin Waves, and Light)

Prüfungsleistung, mündliche Prüfung, Dauer (in Minuten): 25, benotet, 5 ECTS

Anteil an der Berechnung der Modulnote: 100.0 %

weitere Erläuterungen:
There is a bonus of 0.3/0.4 to the grade of the exam for those students who actively participated in the exercise sessions by presenting results at the black board at least twice.

Prüfungssprache: Englisch

Erstablegung: SS 2021, 1. Wdh.: SS 2021 (nur für Wiederholer)

1. Prüfer:

Silvia Viola Kusminskiy