Skip to main content

In spontanious symmetry breaking we minimize lagrangian of zero tempraturetemperature. These lagrangians are phenomenological lagrangianlagrangians like landauLandau or Gizburg-landau or something like mean field. After we found minimumea minimum we expand the priviousprevious lagrangian aroudaround one of the minimumminima (optional(spontanious symmetry breaking)) we get to "mas"mass term" for one field and we see that some field lost their mass. These massless particles play a great roll to convayrole in conveying long range order or collective mode. 

Some of the well-kownknown massless particles are phonon isphonons in superfluid He-4 and Magnons in magnetism or 3-D ising model. People call them goldestone modeGoldstone modes ( collective behavior(primary exitationsexcitations) caused by waving of massless particles). 

All in all, we have to mechanism intwo mechanisms of symmetry breaking in physics. One is goldestoneGoldstone mechanism and the nextsecond is Higgs mechanism. First one for lowshort range forces like between two spin : SIGMA_{ij}J S_i.S_j $\sum_{ij}J S_i\cdot S_j$, and second kind longe range forces : SIGMA_{ij}e^2/{r_i-r_j}^2.$$\sum_{ij}\frac{e^2}{(r_i-r_j)^2}.$$

In spontanious symmetry breaking we minimize lagrangian of zero temprature. These lagrangians are phenomenological lagrangian like landau or Gizburg-landau or something like mean field. After we found minimume we expand the privious lagrangian aroud one of the minimum (optional(spontanious symmetry breaking)) we get to "mas term" for one field and we see that some field lost their mass. These massless particles play a great roll to convay long range order or collective mode. Some of the well-kown massless particles are phonon is superfluid He-4 and Magnons in magnetism or 3-D ising model. People call them goldestone mode ( collective behavior(primary exitations) caused by waving of massless particles). All in all, we have to mechanism in symmetry breaking in physics. One is goldestone mechanism and the next is Higgs mechanism. First one for low range forces like between two spin : SIGMA_{ij}J S_i.S_j, and second kind longe range forces : SIGMA_{ij}e^2/{r_i-r_j}^2.

In spontanious symmetry breaking we minimize lagrangian of zero temperature. These lagrangians are phenomenological lagrangians like Landau or Gizburg-landau or something like mean field. After we found a minimum we expand the previous lagrangian around one of the minima (optional(spontanious symmetry breaking)) we get to "mass term" for one field and we see that some field lost their mass. These massless particles play a great role in conveying long range order or collective mode. 

Some of the well-known massless particles are phonons in superfluid He-4 and Magnons in magnetism or 3-D ising model. People call them Goldstone modes ( collective behavior(primary excitations) caused by waving of massless particles). 

All in all, we have two mechanisms of symmetry breaking in physics. One is Goldstone mechanism and the second is Higgs mechanism. First one for short range forces like between two spin : $\sum_{ij}J S_i\cdot S_j$, and second kind longe range forces : $$\sum_{ij}\frac{e^2}{(r_i-r_j)^2}.$$

Source Link

In spontanious symmetry breaking we minimize lagrangian of zero temprature. These lagrangians are phenomenological lagrangian like landau or Gizburg-landau or something like mean field. After we found minimume we expand the privious lagrangian aroud one of the minimum (optional(spontanious symmetry breaking)) we get to "mas term" for one field and we see that some field lost their mass. These massless particles play a great roll to convay long range order or collective mode. Some of the well-kown massless particles are phonon is superfluid He-4 and Magnons in magnetism or 3-D ising model. People call them goldestone mode ( collective behavior(primary exitations) caused by waving of massless particles). All in all, we have to mechanism in symmetry breaking in physics. One is goldestone mechanism and the next is Higgs mechanism. First one for low range forces like between two spin : SIGMA_{ij}J S_i.S_j, and second kind longe range forces : SIGMA_{ij}e^2/{r_i-r_j}^2.