# Spin chain bosons-fermions

1. Nov 27, 2015

Hello, just as a thought, we are used to describe spin systems of either fermions or bosons (for example, the Ising or Heisenber models, where spins are considered to be all of the same type, in both cases fermions).

However, I was wondering if it makes some sense to have a system where, for example, a chain of spins is created with either bosons (integer spin) or fermions (fractional spins), and where they can interact with each other, that is, considering interaction between fermions and bosons as well.

Thanks!

2. Nov 27, 2015

### king vitamin

When you map the 1D Heisenberg model to bosons or fermions, the resulting theory IS interacting. For the Ising or XY spin chains, the mapping to fermions results in a free theory, but the Heisenberg chain can't be mapped to a free system.

3. Nov 28, 2015