Recent content by bpirvu

hmmm... i guess you mean x^(-1/2) for the power law decay at criticality... this would imply for the critical exponent η from Γ(x)~x^-(d-2+η) that η=3/2... however, what i need is the critical exponent ν of the exponential decay when the system is not critical i.e...

Hi everybody! I'm looking for the critical exponent ν (i.e. the one of the correlation length) of the Heisenberg (i.e. equal coupling in all directions) antiferromagnetic spin-1/2 model in 1D... Furthermore, do you know to which universality class it belongs? Is it true that it's the...

Ah, ok... Many thanks!

Ok, so this is the case if the EM-field can transfer energy to other surrounding systems... However, my question is: what happens if the entire universe consists only of one excited atom and the QED-vacuum?

However there must be some further dissipation process involved if the atom remains in the ground state, no? Under unitary evolution the entire system (atom+EM-field) must return after a certain period of time to its original state. The period "t" must only satisfy exp(-itH)=unity. This is...