Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unitary perturbation theory approach to real-time evolution problems   We discuss a new analytical approach to real-time evolution in quantum
many-body systems. Our approach extends the framework of continuous unitary
transformations such that it amounts to a novel solution method for the
Heisenberg equations of motion for an operator. It is our purpose to illustrate
the accuracy of this approach by studying dissipative quantum systems on all
time scales. In particular, we obtain results for non-equilibrium correlation
functions for general initial conditions. We illustrate our ideas for the
exactly solvable dissipative oscillator, and, as a non-trivial model, for the
dissipative two-state system.

5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat