Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ehrenfest dynamics is purity non-preserving: a necessary ingredient for
  decoherence   We discuss the evolution of purity in mixed quantum/classical approaches to
electronic nonadiabatic dynamics in the context of the Ehrenfest model. As it
is impossible to exactly determine initial conditions for a realistic system,
we choose to work in the statistical Ehrenfest formalism that we introduced in
Ref. 1. From it, we develop a new framework to determine exactly the change in
the purity of the quantum subsystem along the evolution of a statistical
Ehrenfest system. In a simple case, we verify how and to which extent Ehrenfest
statistical dynamics makes a system with more than one classical trajectory and
an initial quantum pure state become a quantum mixed one. We prove this
numerically showing how the evolution of purity depends on time, on the
dimension of the quantum state space $D$, and on the number of classical
trajectories $N$ of the initial distribution. The results in this work open new
perspectives for studying decoherence with Ehrenfest dynamics.

31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
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The categories of this paper are: adap-org
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The categories of this paper are: patt-sol
2
The categories of this paper are: math
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
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The categories of this paper are: hep-ex
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The categories of this paper are: q-fin
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The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph