Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exact Real Time Dynamics of Quantum Spin Systems Using the Positive-P
  Representation   We discuss a scheme for simulating the real time quantum quench dynamics of
interacting quantum spin systems within the positive-P formalism. As model
systems we study the transverse field Ising model as well as the Heisenberg
model undergoing a quench away from the classical ferromagnetic ordered state
and antiferromagnetic Neel state, depending on the sign of the Heisenberg
exchange interaction. The connection to the positive-P formalism as it is used
in quantum optics is established by mapping the spin operators on to Schwinger
bosons. In doing so, the dynamics of the interacting quantum spin system is
mapped onto a set of Ito stochastic differential equations (SDEs) the number of
which scales linearly with the number of spins, N, compared to an exact
solution through diagonalization that in the case of the Heisenberg model would
require matrices exponentially large in N . This mapping is exact and can be
extended to higher dimensional interacting systems as well as to systems with
an explicit coupling to the environment.

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The categories of this paper are: cs
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The categories of this paper are: math
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
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The categories of this paper are: astro-ph
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: quant-ph