Wintersemester 2025/2026

Lehrinhalt

• Foundations of statistics, information, entropy
• Statistical description of physical systems
• Ensembles, density of states
• Irreversibility
• State variables, ideal and real gases, thermodynamic potentials, the fundamental laws of thermodynamics,
• Material constants, equilibrium of phases and chemical equilibrium, law of mass action, ideal solutions
• Fermi- and Bose-statistics, ideal quantum gases
• Phase transitions, critical phenomena (Ising model)
• Transport theory (linear response, transport equations, master equation, Boltzmann equation, diffusion)
• The theory of the solid state as an example for a non-relativistic field theory
• Applications, for example specific heat of solids, thermodynamics of the early universe etc.

Lehrziel

After completing the course the students ¿ have a thorough knowledge and understanding of the laws of thermodynamics and of the description of ensembles in the framework of classical and quantum statistics and there applications to phase transitions, condensed matter, plasma and astrophysics ¿ have acquired the necessary mathematical knowledge and competence for an in-depth understanding of this research field, ¿ have advanced competence in the fields of theoretical physics covered by this course, i.e. the ability to analyze physical phenomena using the acquired concepts and techniques, to formulate models and find solutions to specific problems, and to interpret the solutions physically and communicate them efficiently, ¿ are able to broaden their knowledge and competence in this field of theoretical physics on their own by a systematical study of the literature.

Lehrinhalt

• Quantizing scalar fields
• Canonical quantization and path-integral quantization
• Radiative corrections, renormalization
• Quantizing spin 1 fields
• Dirac equation
• Quantizing spin 1/2 fields
• Interacting fields, S-matrix
• Feynman rules, cross sections
• Quantum Electrodynamics, QED processes at tree level

Lehrziel

After completing the course the students ¿ have a thorough knowledge and understanding of relativistic field equations and the theory of free quantum fields, ¿ will be able to use Feynman rules to calculate on the tree level scattering amplitudes and cross sections for ¿4-theory and for simple reactions in QED, ¿ have acquired the necessary mathematical knowledge and competence for an in-depth understanding of this research field, ¿ have advanced competence in the fields of theoretical physics covered by this course, i.e. the ability to analyze physical phenomena using the acquired concepts and techniques, to formulate models and find solutions to specific problems, and to interpret the solutions physically and communicate them efficiently, ¿ are able to broaden their knowledge and competence in this field of theoretical physics on their own by a systematical study of the literature.

Lehrinhalt

For details about content and exercises see
https://www.mpi-hd.mpg.de/manitop/ParticlePhysics3/index.html

Lehrinhalt

All relevant information can be found under
https://www.thphys.uni-heidelberg.de/~hebecker/Strings/strings.html

Informationen zur Veranstaltung

Lehrinhalt

This advanced theory lecture builds on the statistical physics course (MKTP1) and introduces paradigmatic models of statistical physics and their critical properties near phase transitions.  In particular, we shall discuss the Heisenberg and O(N) vector models, the nonlinear sigma model, the XY model, the Sine-Gordon model, and the spherical model.  By computing their critical behavior, one can understand the phase transitions in many different systems in statistical physics, condensed matter physics and beyond, which belong to the same universality classes.  We will use field theoretic methods and introduce renormalization, epsilon expansion, and duality transformation.

Contents:

1. Landau theory and O(N) vector model
2. Renormalization group and universality
3. Nonlinear sigma model and epsilon expansion
4. Topological excitations in the XY and Sine-Gordon models and the Berezinskii-Kosterlitz-Thouless transition
5. Spherical model and quantum phase transitions
6. Disordered systems
7. Random walks
8. Critical dynamics

Lehrinhalt

After a (condensed) review of the Standard Model of Particle Physics and of features of nature that we do not yet understand, I will present ways to extend the SM at high energies and (theoretical and experimental) guidance we have on our road to find out how nature could look like at shortest distances.

Topics covered in the lecture include Electroweak Symmetry Breaking and its Dynamics, Models of a Composite Higgs, Supersymmetry, Extra Dimensions, and further approaches to understand the puzzling hierarchies we observe in nature. Moreover, I will discuss Effective Field Theory, Flavor Physics & Neutrino Masses, Dark Matter, Baryogenesis and other aspects of Cosmology, as well as the Strong CP Problem and Axions.

Lehrinhalt

Key problems in fundamental physics

Lectures:

(1)  Physical time and the beginning Universe      11.11.

     - Clocks and the vacuum
     - Time coordinates in general relativity and cosmology
          ( proper time, conformal time, cosmic time )
     - Field transformations and frame invariance:
           Is the age of the Universe 13.8 billion years?
     - Physical time for the beginning Universe
     - What is the meaning of expanding space and slowing time?


(2) What is quantum gravity?       25.11.

     - Fields and symmetries
     - General coordinate invariance as a gauge symmetry
     - Quantum field theory for metric or vierbein
     - The role of metric fluctuations
     - Asymptotic safety
     - Lattice approaches and string theory
     - Can one observe quantum gravity effects?


(3) Origin of wave functions and operators for quantum mechanics  9.12.

     - Evolution in classical probabilistic systems
     - Wave functions and time local probabilities in classical statistics
     - Transfer matrix and step evolution operator
     - The non-commuting structures in classical statistics
     - Unitary evolution and quantum mechanics
     - Probabilistic cellular automata as simple quantum systems


(4) Quantum field theory from classical probabilities   20.1.


     - Functional integral approach to quantum field theory
     - Generalized Ising models as "functional integrals“
     - Minkowski and euclidean time
     - Fermions as Ising spins
     - Simple probabilistic cellular automaton  for fermionic quantum field theory
       in one time and one space dimension
    - Vacuum, operators and correlation functions



(5) Cosmological constant and dynamical dark energy

Lehrinhalt

Webseite des Seminars:
https://www.tphys.uni-heidelberg.de/~mielke/ws2025.html

Lehrinhalt

This interdisciplinary block seminar addresses students after the 4th semester from physics, biology, molecular biotechnology, molecular systems engineering and related fields. It is jointly organized by Friedrich Frischknecht (medicine, biology, parasitology), Christine Selhuber-Unkel (experimental biophysics) and Falko Ziebert and Ulrich Schwarz (theoretical biophysics). In our Vorbesprechung on Mon Oct 13 2025 at 4.15 pm, INF 267 (BioQuant), SR 44, we will fix the dates and distribute the subjects.

The ability to move is one of the most fundamental features of biological cells and nearly as important as their ability to grow and divide. A notable exception from this observation is the case of plant cells. However, most other cell types, including bacteria, unicellular eukaryotes and animal cells, usually require some kind of motility in order to function properly. Understanding how cells move is not only interesting from an academic point of view, it is also a subject of large practical relevance, ranging from the design of artificial motility in materials science to medical applications like the control of malaria infection or cancer metastasis. In this seminar, we will introduce the fundamental biological and physical mechanisms underlying cell motility, and discuss state-of-the-art research in this interdisciplinary research field.

The most important physical restrictions for cell motility are that (1) cells are small (typical size 10 micrometer) and (2) immersed in water, which on their small scale is extremely viscous (as quantified by the Reynolds number). One important aspect of the seminar will be to learn about the specific consequences of this situation. In the first half, we will discuss swimming microorganisms, like bacteria, algae, sperm or the parasite trypanosome, which typically move by rotating or beating a flagellum. In the second half, we will discuss cells which crawl or glide on surfaces, like human tissue cells, cancer cells, amoebae or malaria parasites.

Every participant will receive a description of his/her subject and some relevant papers. While preparing your talk, you can meet with the organizers, who will answer questions and give feedback. The talks are then given typically in groups of two or three students, and in three or four blocks in January 2026. This will be counted as obligatory seminar for bachelor students (PSEM, 2+1 CPs) and a mark will be reported for your transcript. For physics master students, you can get 6 CPs for an obligatory master seminar (MVSem), but for this you also have to hand in a 15-20 pages written paper on your subject after the seminar is finished. Similar rules apply for students from other faculties. Active participation during discussions is expected.