Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Charge transfer and coherence dynamics of tunnelling system coupled to a
  harmonic oscillator   We study the transition probability and coherence of a two-site system,
interacting with an oscillator. Both properties depend on the initial
preparation. The oscillator is prepared in a thermal state and, even though it
cannot be considered as an extended bath, it produces decoherence because of
the large number of states involved in the dynamics. In the case in which the
oscillator is intially displaced a coherent dynamics of change entangled with
oscillator modes takes place. Coherency is however degraded as far as the
oscillator mass increases producing a increasingly large recoherence time.
Calculations are carried on by exact diagonalization and compared with two
semiclassical approximations. The role of the quantum effects are highlighted
in the long-time dynamics, where semiclassical approaches give rise to a
dissipative behaviour. Moreover, we find that the oscillator dynamics has to be
taken into account, even in a semiclassical approximation, in order to
reproduce a thermally activated enhancement of the transition probability.

32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org