Pointer states via Decoherence in a Quantum Measurement

摘要: We consider the interaction of a quantum system (spin-1/2) with macroscopic apparatus (harmonic oscillator) which in turn is coupled to bath harmonic oscillators. Exact solutions Markovian Master equation show that reduced density matrix system-apparatus combine decoheres statistical mixture where up and down spins eventually correlate pointer states oscillator), associated probabilities accordance principles. For zero temperature these out be coherent oscillator (apparatus) for arbitrary initial apparatus. Further, we see decoherence time inversely proportional square separation between two correlate. high no longer remain but are Gaussian distributions (generalized states). Spin now nearly diagonal position generalized states. The diagonalization increases bath. off-diagonal elements spin-space decohere over scale goes as peaks spin Zurek’s earlier approximate result consistent our exact results. Our analysis brings importance looking at measurement-like-scenario definite correlations established determine nature basis results demonstrate an unambiguous way this measurement model emerge independent state 03.65.Bz