Condensed matter physics Definition and 76 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. Alpha Roy

    A How to map high symmetry points from a primitive to a conventional cell?

    We usually plot electronic bands with the help of high symmetry points of the irreducible zone of primitive cell of particular material. But if we want to plot bands with conventional cell, we have to map the high symmetry points from primitive cell to conventional cell. so how can we map the...
  2. D

    Solid State Texts on Topological Effects/Phases in Materials

    I am looking to learn about these topological effects or phases in solids. More specifically, I'm trying to find a set of lecture notes or a textbook or some other text that do not shy away from discussing homotopy classes and the application algebraic topology to describe these materials. I...
  3. CyclicAvatar

    PhD in condensed matter theory or theoretical cosmology

    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...
  4. orochi

    Learning about condensed matter physics as a particle physicist

    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...
  5. raz

    A Bloch momentum-space wave functions

    Hello, I wonder if it is possible to write Bloch wave functions in momentum space. To be more specific, it would calculate something like (using Sakurai's notation): $$ \phi(\vec k) = \langle \vec k | \alpha \rangle$$ Moving forward in a few steps: Expanding: $$ \phi(\vec k) = \int d^3\vec r...
  6. ubergewehr273

    I On the anomalous Hall effect

    Hi! Reading through this paper, the Hall resistivity in ferromagnetic materials is given by $$\rho_H = R_0 B + 4 \pi R_s M$$ It is mentioned that ##R_s## (anomalous Hall coefficient) is significantly larger than ##R_0## (ordinary Hall coefficient) and has a strong dependence on temperature...
  7. ubergewehr273

    I Query on spin Hall voltage

    Hi! I'm trying to understand the dependence of spin hall voltage on various parameters of the material. I have been going through this paper, and it is mentioned that $$V_{SH} = 2 \pi R_s L j_x n \mu_B$$ In the equation, only ##L## and ##j_x## seem to be the variables. Does increasing ##L##...
  8. B

    Fermi energy for potassium

    I have completed part a, from which I got the expression: Cv = 3KTn/(T_f) For part b, the first term is the electron contribution and the second term is the phonon contribution. I'm stuck on how to estimate the fermi energy for the potassium metal. I'm thinking I only need to consider the...
  9. M

    Transparent semiconductors

    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...
  10. A

    A The exciton dynamics in the FMO complex

    I want to study the coherence transfer of the excitation in the FMO complex, so I have to solve the Lindblad master equation. Can I treat my system as a two level system?
  11. patric44

    Some questions about reciprocal lattice vectors

    hi guys our solid state physics professor introduced to us this new concept of reciprocal lattice , and its vectors in k space ( i am still an undergrad) i find these concepts some how hard to visualize , i mean i don't really understand the k vector of the wave it elf and what it represents...
  12. H

    A How to calculate density of states (DOS) from 8 energy eigenvalues of a Quantum model calculated by exact diagonalization?

    Data = np.array([-1.61032636, -1.23577245, -0.50587484, -0.28348457, -0.18748945, 0.4537447, 1.2338455, 2.13535718]) print("Data is: ", Data) print(Data.shape) n,bins,patches = plt.hist(Data,bins=4) print("n: ",n) print("bins: ",bins) plt.savefig("./DOS")
  13. 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...
  14. 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...
  15. L

    A What is best way to start learning DMRG for Fermions?

    I want to learn the density matrix renormalization group (DMRG) method in traditional formalism (not MPS). While there are many good introductory level articles available for bosonic (and spin) systems, I have not encountered any introductory level article which deals with fermionic systems i.e...
  16. L

    A How to numerically diagonalize a Hamiltonian in a subspace?

    I want to exactly diagonalize the following Hamiltonian for ##10## number of sites and ##5## number of spinless fermions $$H = -t\sum_i^{L-1} \big[c_i^\dagger c_{i+1} - c_i c_{i+1}^\dagger\big] + V\sum_i^{L-1} n_i n_{i+1}$$ here ##L## is total number of sites, creation (##c^\dagger##) and...
  17. L

    I What is the relation between chemical potential and the number of particles?

    Chemical potential is defined as the change in energy due to change in the number of particles in a system. Let we have a system which is defined by the following Hamiltonian: $$H = -t \sum_i^L c_i^\dagger c_{i+1} + V\sum_i^L n_i n_{i+1} -\mu \sum_i^L n_i$$ where ##c^\dagger (c)## are creation...
  18. L

    A How to choose the number of particles per site in Fermionic DMRG?

    I am doing DMRG (in traditional formalism, not MPS) for Hubbard model H = -t ∑i ∑σci,σ ci+1,σ + U∑ini,σni,σ- In every iteration we add two sites to the system, but how do we set that how many particles are allowed in the system?
  19. li dan

    Can an aircraft using a geomagnetic field generate lift?

    As shown in the figure, the aircraft includes a geomagnetic field convergence layer, which is a superconductor material. The geomagnetic field convergence layer repels the direction of changing the geomagnetic field, so that the geomagnetic field passes between the upper and lower converging...
  20. Z

    "The theoritical minimum" modern equivalent for solid state?

    Hi, for those who don't know, Landau (Lev Davidovitch Landau) had a famous exam called "The theoretical minimum". That exam had to be passed by any future grad-student of his. That test was extremely extensive and difficult, and the student was supposed to be knowledgeable about many fields of...
  21. Joaco

    Studying Condensed Matter Physics Grade vs Materials Science?

    Hi, I'm an undergrad materials engineering student. I am thinking of studying all the way to a PhD as I'm interested on working in research. Right now I work with Semiconductors and I like the field a lot. However, considering what I'm studying, I want to know if it's a good Idea to look for a...
  22. W

    I Empty Lattice approximation/Nearly-free electron model

    Hi all, I am having trouble understanding the some ideas presented in some notes I've been reading, help is greatly appreciated! I've uploaded screenshots of the material I'm referring to below, the last two images are what I'm mainly referencing, and the first few are to provide context...
  23. M

    I Fermi Energy Calculations About Non Parabolic Dispersions

    Greetings! It is easy to understand that for a free electron, we can easily define the energy state density, and by doing the integration of the State density* Fermi-Dirac distribution we will be able to figure out the chemical potential at zero kelvin, which is the Fermi-Energy. Hence, we can...
  24. PrinceWalnut

    Admissions PhD Applications with a low GPA (due to depression in my junior year)

    Hi all, It's a few short months before grad school applications are due, and I find myself in a bit of a dilemma. Prior to my junior year, I knew what I wanted to do is physics research for my career, and I'm particularly interested in biological and condensed matter physics. My skills are more...
  25. thariya

    I The sign of coupling Hamiltonian in CQED

    Hi all, I've always regarded the coupling Hamiltonian for a bosonic cavity mode coupled to a two-level fermionic gain medium chromophore to be of the form, $$H_{coupling}=\hbar g(\sigma_{10}+\sigma_{01})(b+b^{\dagger})$$, where ##b## and ##b^{\dagger}## and annihilation and creation operators...
  26. GiovanniNunziante

    A Derivation of the Heisenberg equation for electron density

    I'm studying plasmons from "Haken-Quantum Field Theory of Solids", and i need some help in the calculation of the equation of motion of eletrons' density \begin{equation} \hat{\rho}_{\overrightarrow{q}} = \frac{1}{\sqrt{V}} \sum_{\overrightarrow{k}}...
  27. Hamza Elkotfi

    A 1D materials : DFT study

    hello dear physicists I will work in my thesis on 1D materials using DFT as a numerical method to find the properietes of these 1D materials I would be very happy if someone can help me with references (books, links, articles, vedios .....) that could help me to advance in my work Thank you
  28. A

    A Why is ##\omega_c \tau >>1## for several revolutions?

    Hey, I read about charge carriers in semiconductors in a magnetic field. They write that for several revolutions ##\omega_c \tau >>1## holds. But I think for one revolution it is ##\omega_c \tau = 2 \pi##. (##\tau## is the scattering time) Why they do not write ##\omega_c \tau >> 2 \pi##...
  29. J

    A Time reversal symmetry and Bloch states

    Hello! The time reversal operator, ##\hat{\Theta}## transforms a Bloch state as follows: ##\hat{\Theta} \psi_{nk}=\psi^*_{nk}##. How does one proceed to prove the condition that ##\psi_{nk}## and ##\psi^*_{nk}## must satisfy in order for our system to be time reversal invariant? Thanks in advance!
  30. J

    A How does parity transformation affect Bloch states?

    Hello! I want to know how does a parity transformation affect Bloch states! I always knew that parity takes the position vector to minus itself (in odd number of dimensions), but I have read that it also takes the Bloch wave vector to minus itself but I have not found a satisfactory proof of...
  31. AD MCFC

    A The Future of "Soft Matter Physics"

    Hi all, I am trying to learn more about this field. Whether you work or have worked in this area or not, I would like to know where Soft Matter is going in terms of theory and applications. Thanks, A.D. *I apologize in advance if there are already many threads specifically addressing this...
  32. G

    Maximum Wavelength and Scattering Angle for Triangular Lattice

    Homework Statement A triangular lattice of lattice spacing ##a=2 ## angstroms is irradiated with x-rays at time zero of wavelength 20 angstroms at an incident angle of ##\alpha =135##. 1) What is the maximum wavelength of the incident x-rays? 2) What is the scattering angle ##\Omega## for...
  33. EnigmaticField

    Programs Apply for a PhD in theoretical condensed matter physics?

    I did research on theoretical formulations in general relativity during my MSc studies. I look forward to pursuing PhD and have searched many universities and some research institutes for suitable research themes, but haven't found many research groups undertaking research consistent with my...
  34. G

    Find ##2\theta## Values from Rotated Crystal and Intensity

    Homework Statement Consider the crystal in the attached image ( (a triangular lattice of white atoms with a triangular basis of grey atoms attached to them at angles of 0, 60 and 120. From a previous problem the fractional coordinates of the atoms in the basis are (0,0)...
  35. J

    A Physical meaning of terms in the Qi, Wu, Zhang model

    The Hamiltonian of the Qi, Wu, Zhang model is given by(in momentum space): ## H(\vec{k})=(sink_x) \sigma_{x}+(sink_y) \sigma_{y}+(m+cosk_x+cosk_y)\sigma_{z} ## . What is the physical meaning of each component of this Hamiltonian? Note: for the real space Hamiltonian(where maybe the analysis of...
  36. S

    Programs Which subfield of physics should I choose?

    Hi everyone; I have a question, and I hope you could answer it. Well, I have a bachelor degree in physics/computer science and I plan to go to a graduate physics program; however, I don’t know which subfield is good for me. I was looking for computational astrophysics, computational condensed...
  37. M

    A What is the value of optical effective electron mass for tin

    What is the value of optical effective electron mass for tin metal (white tin)? What is the value of mean free path for electron of tin metal? At least give me some websites or papers where I can find it?
  38. J

    Solid State Sources to learn about Topological Superconductivity

    Greetings. Does anyone know about any good places to learn about topological superconductivity from? Thanks in advance!
  39. J

    Solid State Books on the Integer Quantum Hall effect

    Hi, does anybody know of any good sources to learn about the Integer Quantum Hall effect from the perspective of theoretical physics? Any suggestion will be appreciated, thanks.
  40. J

    Solid State Books: Weyl semimetals, Topological Insulators

    Hello! What are some good sources(preferably textbooks) to learn about Weyl semimetals? I also want some sources to learn about topological insulators and anything containing the Integer Quantum Hall effect would be great. As an aside, if you have any good book on theoretical condensed matter...
  41. Etienne

    Other How to evaluate the impact of my work anywhere to submit it?

    Greetings all, I am an undergrad working on my first first-author paper in theoretical / computational condensed matter physics (near the computational materials science end of the spectrum) and I am looking to getting it published. My advisor has published in many journals, from mid to high...
  42. DeathbyGreen

    A Eigenvectors of a Floquet Hamiltonian

    I'm trying to recreate some results from a paper: Basically they take the Hamiltonian of graphene near the Dirac point (upon irradiation by a time periodic external field) and use Floquet formalism to rewrite it in an extended Hilbert space incorporating...
  43. G

    Best Written High School Physics Text Books (SAT)

    Advanced Physics (Advanced Science) by Steve Adams & Jonathan Allday from OUP Oxford: and Physics (Collins Advanced Science) 3rd Edition by Kenneth Dobson from Collins Educational: Does anyone know any of these books? I find them very...
  44. DeathbyGreen

    Explaining condensed matter physics and technical subjects to the lay audience...

    I'm currently working in condensed matter theory. Looking at other fields of physics, it seems easy to relate them to a lay audience; for example, in explaining why you study physics, a high energy physicist could go on about the 4 fundamental forces and searches for a unifying theory of...
  45. J

    A Quick question about electron quasi particles... So when the electron is in the material, it seperates into 3 different quasiparticles. But then it says that they cannot exist independently outside of the material. So does that mean the 3 quasiparticles are always...
  46. H

    Solid State Upper division resources in CMT

    Hi everyone. I'll start my master's degree in physics next year. My plan is to continue my studies in theoretical condensed matter physics. So I've decided to increase my knowledge in this area. In my undergrad I took some courses like Intro. to QFT and Many-Body physics. Also I have studied...
  47. J

    Quantum Book on gauge transformations/symmetry & geometrical phases?

    Hello! I will be attending a course on condensed matter physics with emphasis on geometrical phases and I was wondering if the are any good books on gauge transformations, gauge symmetry and geometrical phases that you know of. Thanks in advance!
  48. P

    I Average energy of the electrons at T = 0

    According to the quantum mechanical free electron model the average energy is E=3EF/5 for the 3D case. Nevertheless I saw in a specialised physics book that for the 1D model the average energy at T=0 is 0 and wanted to know if it is the same for the 3D case.
  49. A

    Other Book Suggestions in condensed matter physics

    Can anyone suggest some books which deals with electron correlations in many body systems?The book should cover second quantization,hubbard model,mott transition etc.I'm a beginner in this filed and want to learn from the very basics.
  50. V

    Solid State Books for second quantization and condensed matter

    Hi. I'll be doing a master's degree in nanophysics and working on electron transport in arrays of qubits. I don't know anything (or barely) about the second quantization and would like a book which covers it, and on condensed matter overall. So far I've been told about Bruus&Flensberg's...