The study of physical properties condensed phases of matter, including solids and liquids.

learn more… | top users | synonyms

2
votes
1answer
83 views

Soft Condensed Matter book for self study

I'm a junior undergraduate in physics & materials science. I've had half of a course in quantum mechanics taught out of Townsend's book (We've gone from beginnings of matrix mechanics to the ...
2
votes
0answers
60 views

Numerical problem with Hartree-Fock equations for dilute Bose gas

I have to solve the following set of equations self-consistently: $$\begin{align} n_c(\mathbf{r}) & = \frac{1}{g}\left[\mu - V_{\rm ext}(\mathbf{r}) - 2 g n_{T}(\mathbf{r}) \right] \\[3mm] ...
9
votes
0answers
115 views

Is there a database or a classification of High-temperature superconductors?

I was wondering if there exists a list with all (or most of) the High-$T_c$ superconductor materials. In particular I'd like to know if there are databases or review that classifies them by their ...
3
votes
1answer
75 views

Temperature dependence of magnetic domains

Does the size of magnetic domains depend on temperature ? Not able to find any papers on this subject, maybe because there is no such dependence...
0
votes
2answers
124 views

1D superconductivity does not exist even at zero temperature?

In class Professor claimed that 1D superconductivity does not exist even at zero temperature. I did a preliminary search and found papers on 1D superconductors. Did I or the Prof make a mistake or ...
-1
votes
1answer
25 views

cicumfernatial vector

Once a sheet of graphite is rolled up into a nanotube, the allowed values of k are constrained by the imposition of periodic boundary conditions along the circumferential direction. this periodic ...
4
votes
1answer
67 views

Why use coherent state path integral? What is its motivation or goal?

In almost all textbooks of quantum field theory for high energy, they insert the position and momentum eigenstate to formulate the path integral. While in condensed matter field theory, they insert ...
0
votes
0answers
61 views

Difference between three mutually complementary methods: Raman, Infra-red spectroscopy and inelastic incoherent neutron spectroscopy?

When I read the wiki on Raman spectroscopy, I found a paragraph explaining what system is suitable for using Raman and what others do not. It provide two other method as shown in title: infrared ...
0
votes
1answer
63 views

Derivation of Hartree-Fock equations using 2nd quantization [closed]

I derived the following effective Hamiltonian: $$ H_{eff} = \sum_k{ \left( \, \epsilon_k + \sum_{k_2}{\left(<k \, |<k_2 \, |\,u\,| \, k_2>|\, k> - ...
-1
votes
1answer
43 views

The Definition of Hall effect [closed]

I'm studying in Electricity course in my collage the Hall effect. What is the Hall effect in simple way please?
1
vote
1answer
47 views

Angular momentum partial components of a $k$-dependent pairing potential

I am going over this review on pairing in unconventional superconductors :http://arxiv.org/abs/1305.4609v3 which on page 21 states that for a "regular" function $U(\theta)$, partial components $U_l$ ...
0
votes
1answer
156 views

can a gapless system be a topological state?

For a gapless system without boundary (i.e. in the bulk there is gapless excitation while no clear meaning of boundary excitations like QFT), can it be a topological state? What is the property of EE ...
1
vote
1answer
46 views

What is the underlying transport mechanism of electron drift in metals?

The equations involving drift speed, mobility and conductivity, $v_d=\mu E$ and $\sigma=\mu e n$, treat electrons in a Newtonian way. This model works well in practice (at least in macro scale), but I ...
1
vote
1answer
73 views

What's the difference between charge density wave and charge ordering for superconductors

So far, my understanding is that they are the same. Charge ordering is a phase transition and the material will have charge density waves once it's in a charge ordered state...? This sounds too simple ...
1
vote
1answer
89 views

How can a torus admit half a flux quantum, and why does a vortex induce an AB phase?

There is an issue that I have with the argument given in “Topological Degeneracy of non-Abelian States for Dummies” http://arxiv.org/abs/cond-mat/0607743 , regarding the ground state degeneracy of the ...
0
votes
1answer
29 views

Why higher FAT level implies more signal in XPS analysis?

In XPS analysis, the FAT (Fixed Analyzer Transmission) parameter controls the electrostatic field of an emispheric analyzer, called Pass Energy $E_P$. The FWHM of a peak of signal is given by ...
1
vote
1answer
72 views

How does Galitskii's integral converge?

In V M Galitskii's 1958 paper "$\textit{Energy spectrum of a non-ideal Fermi Gas}$," he builds the following integral as part of a longer expression for the real part of the self-energy (eqn 26'). It ...
1
vote
1answer
86 views

Berry phase in the toric code model and 2D chiral $p$-wave superconductors

When we derive the exchange statistics by moving quasiparticles around a circle in the toric code model we do not mention any Berry phase contribution. Is the Berry phase contribution trivial or it ...
2
votes
0answers
46 views

Proof that magnetic Bloch waves are almost periodic in the reciprocal index

I would like to prove that the magnetic Bloch waves change by a phase factor if you shift their crystal momentum by a reciprocal lattice vector. That is, if $u_{n,\mathbf{k}}(\mathbf{r})$ is a Bloch ...
0
votes
0answers
26 views

Quasi-electron lifetime at Dirac (Weyl) point

I would like to know how one should calculate the electron lifetime with chemical potential at the Dirac point from Fermi Golden Rule: \begin{equation} ...
2
votes
2answers
52 views

Are there materials that strongly (macroscopically) vibrate under light of certain frequencies? If so why?

Picture an imperfect plane of loose particulate matter like sand or silt. Are there materials where if I shine light (not isotropically) on the plane I could get the particles to vibrate with large ...
1
vote
1answer
91 views

What is the difference between Fermi level and Fermi edge?

Just as in title: What is the difference between Fermi level and Fermi edge? My friend makes some research about XPS and he encountered this term. He knows what is Fermi level, but never heard about ...
0
votes
1answer
57 views

Is there any one lattice tight banding model (2D) hosts Dirac points as graphene does?

graphene has a two sublattice structure and it hosts two Dirac points. I wonder if there is some two dimensional lattice geometry which is simpler than honeycomb lattice, but also host Dirac points.
2
votes
0answers
50 views

Difference between a Hamiltonian and its mean-field form?

In most solid state physics text books, BCS theory is introduced in the following way: The authors introduce a mean-field parameter (based on the superconduncting pair) and upon that, they reduce the ...
1
vote
2answers
137 views

Dirac monopole of Berry curvature?

We know that there is an effective "magnetic field" in terms of Berry curvature, which leads to Luttinger's anomalous velocity, etc; and similarly there is also a "magnetic flux", which appears in ...
0
votes
0answers
54 views

Three-dimensional flat bands and how to create them?

Consider a three-dimensional non-interacting system with translational invariance. It is easy to create a two-dimensional flat band by putting this system into a uniform magnetic field. The energy ...
1
vote
0answers
51 views

Photon absorption and emission in 2nd quantization

I am looking for models which describe the interaction of matter (lets take a 1D chain of atoms) with photons, especially the emission and absorption. I would love to see the derivation of models in ...
0
votes
2answers
114 views

Why do Weyl points come in pairs in solid state system?

Quoted from "Beyond Band Insulators: Topology of Semi-metals and Interacting Phases" by Turner and Vishwanath: In 3D lattice models, Weyl points always come in pairs of opposite helicity; this ...
0
votes
0answers
30 views

Numerically evaluating momentum sums

For many-body systems, calculations often involve momentum sums, which are ultimately evaluated numerically for a finite system size $N$. The larger $N$ is, the more accurate the results. Is there ...
0
votes
0answers
67 views

Cooper Pair Breaking and Quasiparticle Excitations

My question concerns the breaking of Cooper pairs and the excitation of quasiparticles. At T = 0 all electrons are condensed in the ground state as cooper pairs. If one increases the temperature one ...
1
vote
0answers
75 views

Derivation of open boundary conditions for Non-Equilibrium Green's Function (NEGF)

It is widely claimed that the Non-Equilibrium Green's Function (NEGF) equations for the study of quantum transport have been derived from the many-body perturbation theory (MBPT). Yet the bridge ...
1
vote
0answers
47 views

Effect of doping in Superconductor

Doping an element (for example element substitution) could be lower down the critical temperature of superconductor, but i don't know the mechanism behind this, is it because more bosons need to ...
1
vote
0answers
38 views

Helium 3 atoms as fermions?

Helium atoms are composite particles so a priori their "single-particle" (in this case single atom) state is very complicated. They are nevertheless well-modeled by elementary fermions models like ...
1
vote
0answers
36 views

Twin and Detwin Crystals [closed]

Hello i would like to ask , what are twin and detwin monocrystals? what has to do with their crystalographic symmetry? any consequences ? any image also would be really helpfull! Thank you
0
votes
0answers
26 views

Rotational invariance of on-site repulsion term in Hubbard model

I'm trying to prove to myself something I assumed that was obvious: that the term $n_{\uparrow} n_{\downarrow} = \widetilde{n}_{\uparrow} \widetilde{n}_{\downarrow}$ where, $n_{\sigma} = ...
1
vote
1answer
64 views

Looking for a specific theory concerning Dark Matter [closed]

I am looking for the name of a theory positing that "empty" space itself is not empty, but has substance, and that "fabric" or "substance" is actually what we call Dark Matter. In theory, dark matter ...
3
votes
3answers
215 views

Difference between DMRG (density matrix renomalization group) and MPS (matrix product states)?

I am learning DMRG recently. I noticed there are many papers both in the DMRG approach and MPS (such as variational matrix product state (VMPS) by F.Verstraete and J.I.Cirac) approach. In my eyes, ...
2
votes
1answer
63 views

Particles, quasiparticles, and “stability”?

So I'm studying Fermi Liquid Theory, which concerns itself with quasiparticle excitations made by superpositions of single-electron wavefunctions. We create particle-like wavepackets which exist for ...
3
votes
1answer
206 views

Particle-Hole transformation in Superconductor

The Bogoliubov - de Gennes equation has a emergent particle-hole symmetry: $$ \mathcal{P}H\mathcal{P}^{\dagger} = -H\text{.} $$ My question is now what happen to the Nambu spinor: $$ ...
3
votes
0answers
171 views

Does Ashcroft and Mermin chapter 13 problem 4 have a misprint?

I've been working through Ashcroft and Mermin to review some aspects of solid state physics and I think problem 4 in chapter 13 might have a misprint. Since there don't seem to be errata available I ...
9
votes
1answer
136 views

Resources for algebraic topology in condensed matter physics

I wanted to know if anyone had any good introductions on algebraic topology for the theoretical physicist? I am particularly interested in applications to condensed matter physics, but would be happy ...
1
vote
2answers
178 views

Why do metals become insulators when oxidized?

I don't know the connection between how forming a new bond with oxygen then changes the density of states to transform the metal into an insulator. It seems like a very powerful transformation.
1
vote
0answers
41 views

Fermi Golden Rule derivation of quasi-electron lifetime

I wonder if there is a detailed derivation of the quasi-electron lifetime: \begin{equation} \frac{1}{\tau_k}=\frac{2\pi}{\hbar}\frac{1}{V^2}\sum_{k', ...
2
votes
1answer
69 views

How do we know that the x-ray pattern is in the reciprocal space? [closed]

I wonder if any one can tell that why do we consider the x-ray pattern (for example, a x-ray pattern on a film for a crystal) in the reciprocal space? (I don't want any explanation about the Ewald ...
2
votes
1answer
39 views

How deep within the sample can the DOS(density of states) be detected by STM(scanning tunnel microscope)?

Using STM equipment, we can get the LDOS(local density of states) on the surface of a sample. I want to know whether the LDOS within the sample(not surface) can be detected by STM. what is the ...
6
votes
2answers
187 views

Is the thermal conductivity of metals affected by magnetic fields?

Especially for a ferromagnet a magnetic field should have a field-induced band shift in the density of states but I wonder if this shift is big enough to be significant and affect the thermal ...
0
votes
0answers
11 views

Is it posssible to numerically simulate a metal layer the same way as a semiconductor one

I need to simulate a schottky junction device. Unfortunately, the software for simulation (AFORS-HET) doesn't allow adding metal (I need to simulate aluminum contact) layers (but it allows to add ...
0
votes
0answers
46 views

Is the saturation magnetization of a thin film different if you apply the field at different directions?

I'm getting different values of the saturation magnetization when I measure them in-plane versus out of plane. The saturation magnetization for the out of plane measurement is greater than in the in ...
0
votes
0answers
24 views

Choosing a basis state for density functional theory calculations

How do we choose basis set of wave functions for expanding the eigenfunctions of the kohn-sham equations? I mean given a material,what should i look for in order to choose my basis functions?
0
votes
1answer
39 views

Why is the vapor pressure important for people that grow films in high vacuum chambers?

I don't understand what this vapor pressure is. The definition from wikipedia is unclear to me. If I look at two materials and one has a higher vapor pressure than the other, does that mean that the ...