Question

what are phonos?how are they different from photons?

Answer 1

Photons are the particles of Electromagnetic field, meaning that they are the quantisation of the EM vibrations. Phonons on the other hand are quasi-particles, and result from the collective excitations of atoms in solid materials. In other words they are the quantisation of atomic vibrations within the lattice of a solid crystal. Sound waves in solid materials are phonons, which is where the term phonon comes from the Greek "phone" (meaning sound) and "on" which is the physicists term for particle. Phonons though can have transverse or longitudinal modes of vibration, whereas photons in EM waves only exhibit transverse modes.