 |
Center for Nonlinear Studies |
Understanding everyday observations of our classical world from seemingly peculiar quantum principles is a fundamental problem. We address it by relying on the insights of quantum Darwinism: We study the emergence of objective classical reality in the example of a central spin undergoing decoherence in a many-spin environment. The system-environment interactions are modeled by imperfect c-not (or "c-maybe") operations, which enables us to tune and quantify the reliability with which the environment monitors the central spin. We derive analytic expressions for the quantum mutual information, Holevo bound, as well as quantum discord between the central spin and an arbitrary fragment of the environment. We consider information extracted by measurements of either the system or collection of environment spins -- environment fragments. We show that agents will inevitably reach the classical plateau (that assures emergence of the consensus about classical reality of the inferred states) by intercepting sufficiently large fragments of the environment, also in the realistic case of non-ideal measurements. We also compute mutual information between two fragments of the environment. This corresponds to the situation responsible for emergence of the objective classical reality from within our quantum Universe where observers find out about the systems of interest by eavesdropping on independent environment fragments.
Host: Gopikrishnan Muraleedharan