Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analysis of entropy of XY Spin Chain   Entanglement in the ground state of the XY model on the infinite chain can be
measured by the von Neumann entropy of a block of neighboring spins. We study a
double scaling limit: the size of the block is much larger then 1 but much
smaller then the length of the whole chain. In this limit, the entropy of the
block approaches a constant. The limiting entropy is a function of the
anisotropy and of the magnetic field. The entropy reaches minima at product
states and increases boundlessly at phase transitions.

27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int