Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Variational Approach to the Spin-boson Model With a Sub-Ohmic Bath   The influence of dissipation on quantum tunneling in the spin-boson model
with a sub-Ohmic bath is studied by a variational calculation. By examining the
evolution of solutions of the variational equation with the coupling strength
near the phase boundary, we are able to present a scenario of discontinuous
transition in sub-Ohmic dissipation case in accord with Ginzburg-Landau theory.
Based on the constructed picture, it is shown that the critical point found in
the general way is not thermodynamically the critical point, but the point
where the second energy minimum begins to develop. The true cross-over point is
calculated and the obtained phase diagram is in agreement with the result of
numerical renormalization group calculation.

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The categories of this paper are: cs
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
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The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
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The categories of this paper are: q-alg
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The categories of this paper are: hep-th
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The categories of this paper are: adap-org
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The categories of this paper are: nlin
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The categories of this paper are: physics
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The categories of this paper are: solv-int
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The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an