What is Condensed matter: Definition and 174 Discussions

Condensed matter physics is the field of physics that deals with the macroscopic and microscopic physical properties of matter, especially the solid and liquid phases which arise from electromagnetic forces between atoms. More generally, the subject deals with "condensed" phases of matter: systems of many constituents with strong interactions between them. More exotic condensed phases include the superconducting phase exhibited by certain materials at low temperature, the ferromagnetic and antiferromagnetic phases of spins on crystal lattices of atoms, and the Bose–Einstein condensate found in ultracold atomic systems. Condensed matter physicists seek to understand the behavior of these phases by experiments to measure various material properties, and by applying the physical laws of quantum mechanics, electromagnetism, statistical mechanics, and other theories to develop mathematical models.
The diversity of systems and phenomena available for study makes condensed matter physics the most active field of contemporary physics: one third of all American physicists self-identify as condensed matter physicists, and the Division of Condensed Matter Physics is the largest division at the American Physical Society. The field overlaps with chemistry, materials science, engineering and nanotechnology, and relates closely to atomic physics and biophysics. The theoretical physics of condensed matter shares important concepts and methods with that of particle physics and nuclear physics.A variety of topics in physics such as crystallography, metallurgy, elasticity, magnetism, etc., were treated as distinct areas until the 1940s, when they were grouped together as solid state physics. Around the 1960s, the study of physical properties of liquids was added to this list, forming the basis for the more comprehensive specialty of condensed matter physics. The Bell Telephone Laboratories was one of the first institutes to conduct a research program in condensed matter physics.

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  1. physicsxanime

    Seeking advice on how to study condensed matter theory

    TL;DR Summary: I am asking for how to study CMT Any advice in connecting concepts and building intuition for condensed matter? Sometimes I can do some problems operationally, but I can't see connection between different problems and doesn't have a mental model or intuition? I can think of read...
  2. gaiussheh

    I Insulator band gap and applied voltage?

    I got confused by the band theory. Does the band gap imply the voltage needed to conduct? This seems to be ridiculous. The band gap of a typical insulator is on the order of a few eV. Hence, if you give electrons 10 eV, they jump to the conduction band. But surely you can't turn an insulator...
  3. physicsxanime

    A Looking for study group to hack on basic theory in condensed matter

    Hi Pholks, I just change my field of study from cosmology to condensed matter and I have a severe lack of knowledge in condensed matter. Having only some concepts in quantum mechanics and field theory, I would like to ask if there are anyone who wants to setup a weekly study group to discuss...
  4. physicsxanime

    Calculating exciton Green's function on a tight binding chain

    Honestly, I have no real idea. I know for sure the equation connects the initial state ##|\Psi^N_0>##to a final state ##|\Psi^{N+1}_0>##, ##E## is the energy and ##E^N_0## etc are the energy of the initial state and final state. I also know that these energy are related to conduction band and...
  5. P

    I Hartree-Fock: Feynman diagrams vs perturbation theory

    I am trying to understand Green's functions in many-body theory for condensed matter. After much struggle, I managed to calculate my first diagrammatic expansion. However I am perplexed by getting more of the usual results. The Hartree–Fock energy result I know from second quantization can be...
  6. StanislavD

    A Pairing of electrons in superconductors

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  7. T

    I Intersection of Condensed Matter Theory + High Energy Physics

    Hey all, I was just wondering where I could find a current review of the major problems that are being discussed at the intersection of condensed matter theory and high energy theory (+maybe quantum information)? Just looking for some inspiration on what the most "popular" problems being...
  8. StanislavD

    A Decay of supercurrents connected to non-superconducting zones?

    This question is more complicated than it seems, most physicists cannot answer it unambiguously and there is no experiments to the issue. Imagine, a persistent supercurrent flows in a SC aluminum ring. Then we connect the SC aluminum ring (without solder) to an aluminum wire, the second end of...
  9. D

    A Investigating the dielectric constant of a pure polar liquid

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  10. kevmeister

    A What is the meaning of the (A x B) when talking about CDWs?

    What is the A x B labeling referring to when discussing charge density waves? For example the 2x2 CDW structure in TiTe2 (link). Is it I have searched through a fair amount of literature (from Grüner to more recent experimental studies) and it doesn't seem to be explained anywhere that I've...
  11. hudsonj

    Intro Physics Pop-sci books about condensed matter physics or superconductivity?

    I was wondering if anyone knows of any technical pop-sci books about condensed matter physics and/or superconductivity that are at the technical level of something like the "A Very Short Introduction" series or the Feynman lectures. That is, something that goes sufficiently into depth into the...
  12. A

    Solid State Best resources to learn topological condensed matter in 2022?

    Hello, I was not sure whether this should belong to this section or the condensed matter section. I am wondering if after about 15 years in research in topological condensed matter, there exist well-recognized references for beginners in the topic. Books or courses but also review articles...
  13. StanislavD

    A Experiments for temperature dependence of persistent supercurrent?

    Imagine, in a mercury ring (superconductivity below Tc=4.15 K) we establish a persistent supercurrent. Then we organize temperature cycles (T-cycles) in the cryostat, from 3 K to 2.5 K and back. According to the BCS theory of superconductivity, the pair density decreases at warming, i.e. a not...
  14. cemtu

    Solid State Good Condensed Matter Physics Books and Semiconductor Physics Books

    Can you please recommend me some condensed matter physics study books and semi-conductor physics study books? Much Appreciated!
  15. P

    Undergraduate modern physics and condensed matter physics courses

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  16. Faizan Samad

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    I know in RVB theory that neighbouring Copper atoms form singlet pairs via the superexchange "force". Upon doping with holes, these neutral singlet RVB pairs become mobile and charged and are able to superconduct. I know that the resonating valence bonds are in the copper 3d(x^2-y^2) orbital and...
  17. CyclicAvatar

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    Hi all, I just graduated from my master's program in theoretical physics. I did 60% of the coursework in high energy physics and rest in condensed matter theory plus a few experimental physics courses. I did my master's thesis in what can be called as theoretical cosmology, studying particle...
  18. orochi

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    I am on my first year of my master's degree in nuclear and particle physics, and right now i am ending my first semester, where i decided to take a course in physics of semiconductors. As i end this semester i start to wonder if there was any use in learning about this subject, as it seems like...
  19. P

    A How to read modern condensed matter field research

    Hi all, (I also posted this in the high energy theory section since my impression is there is a deep interplay between modern condensed matter theory and high energy theory). Some background: I'm interested in the interplay between condensed matter and high energy theory. I'm a bit more than...
  20. mcas

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    We have a one dimensional lattice with a lattice constant equal to a (I'm omitting vector notation because we are in 1D). The reciprocal lattice vector is k_n=n\frac{2 \pi}{a}. So to get the nearest neighbour approximation I need to sum over k = -\frac{2 \pi}{a}, 0, \frac{2 \pi}{a}. If I...
  21. U

    What Explains the Lack of Current in a PN Junction at Equilibrium?

    Consider a PN junction doped with say phosphorous on the N side, and Boron on the P side. Initially, there is an opportunity for the electrons just below the N conduction band to drop to the lower available energy states just above the P valence band. This leaves the N side positively charged...
  22. W

    A Define spin operators for numerical groundstate obtained by ED

    Hi, I want to measure spin components of a ground state of some models. These ground states are obtained by ED. The states for constructing the Hamiltonian are integers representing spins in binary. As the ground state (and the other eigenvectors) are now not anymore in a suitable representation...
  23. S

    A Berry phase in condensed matter

    I am trying to understand how is topology used to characterize materials. So I understand that to calculate the Berry phase you will parameterize your Hamiltonian and change this parameter in some way and return to the initial value. What I do not understand is what does this changing of...
  24. C

    I How do shockwaves in a 1D linear lattice work?

    I am struggling to understand shocks in a one dimensional lattice with a linear spring connecting the masses. Say I have a one dimensional lattice with a linear spring constant, k and lattice spacing a. If the particles in the lattice has mass, m then my speed of sound c is a*sqrt(k/m). That is...
  25. M

    Potential solution:Uses of Transparent Semiconductors: FTO and ITO explained

    Summary:: What is the advantage of transparent semiconductors such as Fluorine doped tin oxide over main semiconductors? What is the advantage of transparent semiconductors such as Fluorine doped tin oxide (FTO) and Indium tin oxide (ITO) over main semiconductors? Please explain the uses of...
  26. F

    Programs Condensed Matter PhD Program Choice - Advice Needed

    Hi, I don't want to be too specific here, but specific enough for relevant advice. I'm finishing a Masters in Physics and am lucky to have been made offers by 2 excellent institutes: a Max Planck Graduate Centre (MP), and at Oxford UK. Both are in experimental condensed matter; Weyl...
  27. IreneFerri

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    My name is Irene and I've just started my PhD. at the University of Barcelona (October, 2020). I have a Physics degree and a Master in Computational Modelling. I work in a research group named ClabB (complexity lab Barcelona) where I develop a large scale opinion model using Monte-Carlo...
  28. davidbenari

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    This is going to be controversial and might even be taken down, but I think what I will say is absolutely true, and I'm sorry if it offends people. I'm applying for the second time to condensed matter PhDs. I was in a group that did a lot of device fabrication as part of their experiments and...
  29. teame Yitbarek

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    I have my MSc in 'Computational condensed matter physics'. I used VASP package for simulation during my MSc. and i am also well experienced in FORTRAN programming language. Can anyone give me short note about 'PhD in computational physics'? so that can continue my PhD in 'Computational Physics'.
  30. Q

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    Assuming the electrons are non interacting and spin degenerate, the conductance of a quasi one dimensional quantum wire is quantised in units of 2e^2/h. For small voltages, we simply count how many bands have their bottoms below the chemical potential and multiply this by 2e^2/h. This is due to...
  31. Jamister

    Solid State Book for a graduate condensed matter course

    What books are recommended for a course in condensed matter physics at a graduate level?
  32. G

    Physics Industry job prospects for a condensed matter computational physicist

    I'm working on a PhD in condensed matter computational physics, particularly with method development. My plan is to go into industry afterwards, and out of curiosity I've been looking at job listings. It doesn't look good to be honest. Listings for physicists mainly require some type of lab...
  33. Z

    Which school is stronger in condensed matter theory?

    Hey guys. I have offers to do summer research at both Brown University and University of Chicago this summer, and I was wondering which school has a stronger department in regards to condensed matter theory. Personally, I think it's University of Chicago, but I'm not too sure and I'd appreciate...
  34. C

    A What are the frontiers and challenges in condensed matter physics?

    In your opinion, what are the main challenges for future condensed matter physics? What type of material systems are more desirable to discover? Which quantum properties are the most interesting to demonstrate for future devices working at room temperature and ambient pressure (besides...
  35. MathematicalPhysicist

    Problem 7.7 and its solution from A Quantum Approach to Condensed Matter

    Well, I don't understand the integral part of ##1/(VD) = \int_0^{\hbar \omega_D}\frac{\tanh(\beta E/2}{E}dE## and ##\tanh(\beta E/2) \approx 1-2\exp(-\beta E)##, then he writes the following (which I don't understand how did he get it): $$\frac{1}{VD} = \sinh^{-1} (\hbar \omega/\Delta(0)) =...
  36. binbagsss

    Does the quantum Hall effect come under the category condensed matter?

    Title? Thanks. I think it does since these do : - Quasi particles - Collective behaviour of particles - Phase transitions Any others?
  37. L

    A Why do we study quantum spin liquids?

    What kind of research is currently going on in the field of quantum spin liquids and why do we study spin liquids?
  38. M

    Programs Doing a PhD in both computational and experimental condensed matter physics?

    I am torn between computational and experimental condensed matter physics for my PhD. My focus is on low dimensional systems (e.g. electron correlation/transport, broken symmetry at the boundaries). I'm currently in the process of applying for graduate schools, and so far, I've chosen all my...
  39. TheBigDig

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  40. haushofer

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    Dear all, in the context of my teaching I was wondering what exactly the explanation is of how a mirror works at the atomic level. Apparently, the fact that reflecting materials are often also good conductors and hence big energy bands helps reflecting the photons. Does someone know a nice set...
  41. L

    A Quantum statistical canonical formalism to find ground state at T

    For my own understanding, I am trying to computationally solve a simple spinless fermionic Hamiltonian in Quantum Canonical Ensemble formalism . The Hamiltonian is written in the second quantization as $$H = \sum_{i=1}^L c_{i+1}^\dagger c_i + h.c.$$ In the canonical formalism, the density...
  42. Alex Petrosyan

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    Hello everyone, I'm a Physics student on a gap year, doing a bit of work ATM. I'm going to come back in October this year to do a one-year Masters' at Cambridge, and I'm faced with a tough choice: A) Specialize in Astrophysics/cosmology, which is something that I'm not as good at, but really...
  43. L

    Can we study an odd number sized lattice model at half filling?

    So one can numerically study (I am interested in exact diagonalization) any 1D lattice model with ##L## sites and ##N## number of particles. At half filling, ##L/N = 2##. My question to a professor was that can we study a system of size ##L = 31## at half filling? He replied yes, there is a way...
  44. L

    I How do irrational numbers give incommensurate potential periods?

    I am trying to understand Aubry-Andre model. It has the following form $$H=∑_n c^†_nc_{n+1}+H.C.+V∑_n cos(2πβn)c^†_nc_n$$ This reference (at the 3rd page) says that if ##\beta## is irrational (rational) then the period of potential is quasi-periodic incommensurate (periodic commensurate) with...
  45. S

    Courses Math courses for Theoretical Condensed Matter

    I'm a physics and math major, going into my 3rd year. Suppose I want to do research in theoretical aspects of condensed matter. What would be the mathematics I should be learning as an undergraduate? Here is a rundown of courses I'm considering taking next year: Abstract Algebra: it seems a...
  46. A

    A Manipulations with Hubbard operators

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  47. P

    I Free electron gas band structure?

    How can I see, by looking at a band structure if the substance in question can be viewed as a free electron gas (FEG) or not? What characterizes a FEG in a bandstructure plot? Thanks in advance!
  48. A

    A Create Hamiltonians in condensed matter with group theory

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