Pointer states via Decoherence in a Quantum Measurement

@article{Venugopalan1999PointerSV,
  title={Pointer states via Decoherence in a Quantum Measurement},
  author={Anu Venugopalan},
  journal={Physical Review A},
  year={1999},
  volume={61},
  pages={012102}
}
We consider the interaction of a quantum system (spin-1/2) with a macroscopic quantum apparatus (harmonic oscillator) which in turn is coupled to a bath of harmonic oscillators. Exact solutions of the Markovian Master equation show that the reduced density matrix of the system-apparatus combine decoheres to a statistical mixture where up and down spins eventually correlate with pointer states of the apparatus (harmonic oscillator), with associated probabilities in accordance with quantum… 
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