The study of physical properties condensed phases of matter, including solids and liquids.
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How does electricity propagate in a conductor?
On a systems level, I understand that as electrons are pushed into a wire, there is a net field and a net electron velocity. And I've read that the net electron drift is slow. But electricity ...
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4answers
1k views
Books for Condensed Matter Physics
What are some good condensed matter physics books that can fill the gap between Ashcroft & Mermin and research papers? Suggestions for any specialized topics (such as superconductivity, CFT, ...
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3answers
891 views
Are elementary particles actually more elementary than quasiparticles?
Quarks and leptons are considered elementary particles, while phonons, holes, and solitons are quasiparticles.
In light of emergent phenomena, such as fractionally charged particles in fractional ...
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1answer
587 views
What is the relationship between string net theory and string / M-theory?
I've just learned from this one of Prof. Wen's answers that there exists a theory called string net theory. Since I've never heard about this before it picks my curiosity, so I`d like to ask some ...
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5answers
2k views
Do photons gain mass when they travel through glass?
Please correct me if I'm wrong, but I believe that photons slow down when travelling through glass. Does this mean they gain mass? Otherwise, what happens to extra kinetic energy?
I understand now ...
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5answers
1k views
Simple models that exhibit topological phase transitions
There are a number of physical systems with phases described by topologically protected invariants (fractional quantum Hall, topological insulators) but what are the simplest mathematical models that ...
11
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5answers
2k views
What does it mean for a Hamiltonian to be gapped?
I've read some papers recently that talk about gapped Hamiltonians or gapless systems, but what does it mean?
Edit: Is an XX spin chain in a magnetic field gapped? Why or why not?
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1answer
279 views
Condensed matter physics for mathemematicians
What is a good way for me to learn the basics of condensed matter physics? I'd like to get a better understanding of the fundamentals behind recent technological developments like OLEDs, applications ...
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10answers
1k views
What is spontaneous symmetry breaking in QUANTUM systems?
Most descriptions of spontaneous symmetry breaking, even for spontaneous symmetry breaking in quantum systems, actually only give a classical picture.
According to the classical picture, spontaneous ...
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4answers
2k views
A pedestrian explanation of conformal blocks
I would be very happy if someone could take a stab at conveying what conformal blocks are and how they are used in conformal field theory (CFT). I'm finally getting the glimmerings of understanding ...
13
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3answers
1k views
Good reading on the Keldysh formalism
I'd like some suggestions for good reading materials on the Keldysh formalism in a condmat context. I'm familiar with the imaginary time, coherent state, path integral formalism, but lately I've been ...
12
votes
2answers
1k views
What is a resonating valence bond (RVB) state?
There's something known as a "resonating valence bond" (RVB) state, which plays a role in at least some attempts to understand physics of high-$T_c$ superconductors. This, roughly, involves a state ...
11
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3answers
847 views
Condensed matter application of AdS/CFT
I'm going to be teaching a course on gauge/gravity duality (aka AdS/CFT) in the winter.
The focus will be on applications in particle theory including $N=4$ SYM, the viscosity/entropy bound, and ...
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1answer
325 views
A physical understanding of fractionalization
all! Is there a physical understanding of fractionalization in condensed matter physics? The textbook approach is theoretical, not physical. I'm thinking of spin-charge separation for electrons, the ...
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1answer
283 views
Why path integral approach may suffer from operator ordering problem?
In Assa Auerbach's book (Ref. 1), he gave an argument saying that in the normal process of path integral, we lose information about ordering of operators by ignoring the discontinuous path.
What did ...
8
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3answers
189 views
References on the physics of anyons
Anyone know some good introductory references on the physics of anyons?
3
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1answer
321 views
What conductance is measured for the quantum spin Hall state when the Hall conductance vanishes?
It's probably just a definition, but what did König et al. actually measure when he confirmed
the existence of surface states in CdTe/HgTe/CdTe quantum wells (see http://arxiv.org/abs/0710.0582)?
...
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2answers
487 views
Basic questions in Majorana fermions
Why any fermion can be written as a combination of two Majorana fermions? Is there any physical meaning in it? Why Majorana fermion can be used for topological quantum computation?
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2answers
396 views
What is the mathematical reason for topological edge states?
There are many free fermion systems that possess topological edge/boundary states. Examples include quantum Hall insulators and topological insulators. No matter chiral or non-chiral, 2D or 3D, ...
11
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1answer
433 views
Emergent symmetries
As we know, spontaneous symmetry breaking(SSB) is a very important concept in physics. Loosely speaking, zero temprature SSB says that the Hamiltonian of a quantum system has some symmetry, but the ...
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1answer
203 views
Is edge state of topological insulator really robust？
I am a little confused! Some people are arguing that the gapless edge state of Topological insulator is robust as long as the time reversal symmetry is not broken，while other people say that it is ...
7
votes
3answers
347 views
Is there a connection between the fluctuation-dissipation theorem and the Green–Kubo relations?
Is there a connection between the fluctuation-dissipation theorem and the Green–Kubo relations? I have a hard time finding out if there is a relation and what it is, because the ...
4
votes
1answer
183 views
Chiral edge state as topological properity of bulk state
As far as I know, quantum hall effect and quantum spin hall effect has chiral edge state. Chiral edge state is usually closely related with delocalization, since back scattering is forbidden. However, ...
4
votes
1answer
346 views
Hit a bottle of beer on the top with another causes the first to spit all the gas, why?
So, on the other day me and my colleges were discussing the following phenomena:
Pick two open bottles of beer. With the bottom of the first, hit the second on the bottleneck, in the following way: ...
9
votes
3answers
333 views
Introduction to Anderson localization [closed]
I find Anderson's original paper too terse. I am looking for something that introduces me gently to the subject so that I can understand Anderson's paper and other literature. What references are out ...
8
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2answers
1k views
How do Dirac fermions arise in graphene, and, what significance (if any) does this have for high-energy physics?
Graphene has a honeycomb lattice (in the absence of defects and impurities). By considering the low-energy limit of the half-filled Hubbard model used to model the strongly interacting electron gas we ...
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0answers
255 views
Is the “particle number” of “electrons” well defined in Wen's string-net theory of elementary particles?
According to professor Wen's string-net theory(Colloquium: Photons and electrons as emergent phenomena, Levin and Wen, Rev. Mod. Phys. 77, 871(2005), see e.g. http://arxiv.org/abs/cond-mat/0407140), ...
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2answers
221 views
In condensed matter simulations, how is particle number density computed in practice?
I have been reading a recent paper. In it, the authors performed molecular dynamics (MD) simulations of parallel-plate supercapacitors, in which liquid resides between the parallel-plate electrodes. ...
5
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1answer
406 views
Yet another question on the Lindhard function
Here's another question concerning the Lindhard function as used in the physical description of metals.
First we define the general Lindhard function in the Random Phase approximation as
...
5
votes
2answers
614 views
How much can AdS/CMT tell us?
I will begin my research on AdS/CMT, however I find AdS/CMT is only a phenomelogical method, so I want to know can AdS/CMT give some results the condensed matter physicists can not give, or even ...
7
votes
3answers
357 views
Mathematical rigorous introduction to solid state physics
I am looking for a good mathematical rigorous introduction to solid state physics. The style and level for this solid state physics book should be comparable to Abraham Marsdens Foundations of ...
6
votes
1answer
159 views
Thermodynamic limit “vs” the method of steepest descent
Let me use this lecture note as the reference.
I would like to know how in the above the expression (14) was obtained from expression (12).
In some sense it makes intuitive sense but I would ...
5
votes
1answer
215 views
A question about Haldane's conjecture
Haldane's conjecture states that the integer spin antiferromagnetic Heisenberg chains have a gap in the excitation spectrum. However, the dispersion relation of the antiferromagnetic spin wave is ...
5
votes
1answer
175 views
Does there exist a nonrelativistic physical system in which the effective long-distance fields violate spin/statistics?
The nonrelativistic Schrodinger field allows spin independent of statistics, so that you can imagine a nonrelativistic Schrodinger scalar field with Fermionic statistics, or a Schrodinger spinor field ...
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votes
2answers
257 views
Transition between 2D and 3D quantum systems
Quantum Hall effect and anyonic particles are examples that occur in a two-dimensional system. However, experiments for such systems can only be realized in a pseudo-2D environment, where the third ...
4
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1answer
226 views
Counterexamples to the bulk-boundary correspondence (topological insulators)
In the literature on topological insulators and superconductors the 'bulk-boundary correspondence' features quite heavily. One version of this conjecture says roughly: "At an interface between two ...
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vote
2answers
101 views
Reference needed for Iron-based superconductors
Iron-based superconductor is a class of high-$T_c$ superconductors discovered in 2008.
Are there any review papers about these superconductors yet? If not, which are the key papers in the field?
5
votes
1answer
353 views
How can one localize the massless fermions in Dirac materials?
I noticed that finite electric potential cannot localize the low energy excitations in a graphene sheet. Is it possible to localize the massless fermions in the surface band of topological insulators ...
2
votes
3answers
139 views
Why is the Coulomb potential in pseudo-2D experiments proportional to the logarithm of distance?
Inspired by this question, I ask another. Theoretically, Coulomb potential in 2D is proportional to the logarithm of distance; In experiments, though electrons are constrained in a pseudo-2D ...
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0answers
74 views
Phonon-polariton literature resources? [closed]
What is a good resource for studying phonon-polaritons?
2
votes
2answers
161 views
Has BCS Cooper pair condensate been observed in experiment?
Feshbach resonance in s-wave scattering states a BCS Cooper pair condensation at B-field just above the resonance where the scattering length a <0. Just wondering if the condensation has been ...
1
vote
1answer
114 views
Hamiltonian of a simple graph
I have a spin system:
As shown in the picture, there are two spins S1 and S2, and a pair of interactions between them. One is a ferromagnetic interaction and the other is anti ferromagnetic ...
1
vote
1answer
985 views
Which derivation of drift velocity is correct?
In the derivation of drift velocity I have seen two variations and want to know which one's correct.
$s=ut+\frac{at^2}{2}$
Assume that the drift velocity of any electron in any conductor is :
...
0
votes
0answers
27 views
Impurity scattering [duplicate]
Possible Duplicate:
Impurity scattering temperature dependence
Is there any temperature dependence of relaxation time in impurity scattering of conducting electrons? It seems to me that ...
