Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Modified Perturbation Theory Applied to Kondo-Type Transport through a
  Quantum Dot under a Magnetic Field   Linear conductance through a quantum dot is calculated under a finite
magnetic field using the modified perturbation theory. The method is based on
the second-order perturbation theory with respect to the Coulomb repulsion, but
the self-energy is modified to reproduce the correct atomic limit and to
fulfill the Friedel sum rule exactly. Although this method is applicable only
to zero temperature in a strict sense, it is approximately extended to finite
temperatures. It is found that the conductance near electron-hole symmetry is
suppressed by the application of the magnetic field at low temperatures.
Positive magnetoconductance is observed in the case of large electron-hole
asymmetry.

31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat