Condensed matter physics Updated 2024-12-15 +Created 1970-01-01
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Condensed matter physics is one of the best examples of emergence. We start with a bunch of small elements which we understand fully at the required level (atoms, electrons, quantum mechanics) but then there are complex properties that show up when we put a bunch of them together.
Includes fun things like:
As of 2020, this is the other "fundamental branch of physics" besides to particle physics/nuclear physics.
Condensed matter is basically chemistry but without reactions: you study a fixed state of matter, not a reaction in which compositions change with time.
Just like in chemistry, you end up getting some very well defined substance properties due to the incredibly large number of atoms.
Just like chemistry, the ultimate goal is to do de-novo computational chemistry to predict those properties.
And just like chemistry, what we can actually is actually very limited in part due to the exponential nature of quantum mechanics.
Also since chemistry involves reactions, chemistry puts a huge focus on liquids and solutions, which is the simplest state of matter to do reactions in.
Condensed matter however can put a lot more emphasis on solids than chemistry, notably because solids are what we generally want in end products, no one likes stuff leaking right?
But it also studies liquids, e.g. notably superfluidity.
One thing condensed matter is particularly obsessed with is the fascinating phenomena of phase transition.
Figure 1.
xkcd 2933: Elementary Physics Paths
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Video 1.
What Is Condensed matter physics? by Erica Calman
. Source. Cute. Overview of the main fields of physics research. Quick mention of his field, quantum wells, but not enough details.
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Quantum matter physics course of the University of Oxford Updated 2024-12-15 +Created 1970-01-01
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Notes/book: www-thphys.physics.ox.ac.uk/people/SteveSimon/QCM2022/QuantumMatter.pdf Marked as being for Oxford MMathPhys, so it appears that this is a 4th year course normally. TODO but where is it listed under the course list of MMapthPhys? mmathphys.physics.ox.ac.uk/course-schedule
  • Fermi Liquids
    • Weakly Interacting Fermions
    • Response Functions and Screening
      • Thomas Fermi
      • RPA
      • Plasmons
    • Landau Fermi Liquid Theory
  • Superfluidity
    • Two Fluid Model and Quantized Circulation
    • Landau Criterion for Superfluidity
    • Two Fluid Model for Superconductors
      • London Theory
      • Flux Vortices
      • Type I and Type II superconductors
    • Microscopic Superfluidity
      • Coherent States
      • Bose Condensation
      • Gross Pitaevskii Equation
      • Off Diagonal Long Range Order
      • Feynman Theory of Superfluidity (in book, but will skip in lectures. Not examinable)
    • Ginzburg Landau Theory of Superfluids
      • Neutral Superfluids
      • Charged Superfluids
      • Anderson - Higgs Mechanism
      • Rederviation of London Equations
      • Ginzburg - Landau Parameter and Type I/II revisited
      • Vortex Structure
  • BCS Theory of Superconductors
    • Phonons
    • The Cooper Problem
    • BCS wavefunction
    • Bogoliubov Excitation Spectrum
    • Majorana Physics
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Second-order phase transition Updated 2024-12-15 +Created 1970-01-01
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The more familiar transitions we are familiar with like liquid water into solid water happen at constant temperature.
However, other types of phase transitions we are less familiar in our daily lives happen across a continuum of such "state variables", notably:
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Superconductivity is a a form of superfluidity Updated 2024-12-15 +Created 1970-01-01
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We know that superfluidity happens more easily in bosons, and so electrons joins in Cooper pairs to form bosons, making a superfluid of Cooper pairs!
Isn't that awesome!
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