Transverse and Longitudinal Sound Waves

narra
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What causes sound waves to be solely longitudinal in gas, liquid, and plasmas, but enables longitudinal and transverse in solids? Also, does solids only mean crystalline structures or are amorphous materials also able to support transverse sound waves?
 
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Hi,

Sound waves travels in all except perfect vacuum.
In crystals we have 3 waves (two transverse and one longitudinal waves)
 
I was of the understanding that only Longitudinal sound (Pressure) waves could propagate in gas, liquid, and plasma. Whereas in solids, both longitudinal and transverse sound waves were possible, and hence my first question. Am I mistaken?
 
Fluids don't support shear stresses. All solids do, so it shouldn't matter if they are amorphous or crystalline.
 
So it is the solids lattice (structural bonds) which promote shear stress, thus allowing lateral density modulation?
 
If you displace a section of a liquid in the transverse direction there is no change in the energy of the liquid, since no chemical bonds are being stretched. Thus there is no restoring force, and no transverse mode.
 
From the BCS theory of superconductivity is well known that the superfluid density smoothly decreases with increasing temperature. Annihilated superfluid carriers become normal and lose their momenta on lattice atoms. So if we induce a persistent supercurrent in a ring below Tc and after that slowly increase the temperature, we must observe a decrease in the actual supercurrent, because the density of electron pairs and total supercurrent momentum decrease. However, this supercurrent...
Hi. I have got question as in title. How can idea of instantaneous dipole moment for atoms like, for example hydrogen be consistent with idea of orbitals? At my level of knowledge London dispersion forces are derived taking into account Bohr model of atom. But we know today that this model is not correct. If it would be correct I understand that at each time electron is at some point at radius at some angle and there is dipole moment at this time from nucleus to electron at orbit. But how...
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