Block purity in a long-range Kitaev chain


The purity of blocks of 10- and 30-spins in a long-range Kitaev model is calculated by exact diagonalization. The obtained block purity is a measure of entanglement and number fluctuations between the block and the chain it is embedded in. A phase diagram is constructed from the purity when it is expressed as a function of the range parameter and relative chemical potential. It is found that the block purity can differentiate between the magnetic phases of the long-range Kitaev model: it is small in the region corresponding to the antiferromagnetic phase and large in the paramagnetic region.