دانلود گزارش کارورزی و کار آموزی

چکیده : 

We study localization properties of disordered bosons and spins

in random fields at zero temperature. We focus on two representatives

of different symmetry classes, hard-core bosons (XY magnets)

and Ising magnets in random transverse fields, and contrast

their physical properties. We describe localization properties using

a locator expansion on general lattices. For 1d Ising chains, we

find non-analytic behavior of the localization length as a function

of energy at ω = 0, ξ−1(ω) = ξ−1(0) + A|ω|α, with α vanishing

at criticality. This contrasts with the much smoother behavior predicted

for XY magnets. We use these results to approach the ordering

transition on Bethe lattices of large connectivity K, which mimic

the limit of high dimensionality.