Revealing the emergence of classicality in nitrogen-vacancy centers

TL;DR

This study demonstrates how classical objectivity emerges from quantum systems by observing quantum Darwinism in nitrogen-vacancy centers, showing redundant information imprinting onto the environment that leads to classical reality.

Contribution

It introduces a novel dynamical decoupling scheme to measure and control nuclear spins interacting with NV centers, revealing the emergence of classicality from quantum decoherence.

Findings

Redundant information is imprinted onto nuclear spins during decoherence.

Demonstration of creation of entangled system-environment states relevant to quantum metrology.

First laboratory verification of classical objectivity emerging from quantum systems.

Abstract

The origin of classical reality in our quantum world is a long-standing mystery. Here, we examine a nitrogen vacancy center evolving naturally in the presence of its environment to study quantum Darwinism - the proliferation of information about preferred quantum states throughout the world via the environment. This redundantly imprinted information accounts for the perception of objective reality, as it is independently accessible by many without perturbing the system of interest. To observe the emergence of redundant information, we implement a novel dynamical decoupling scheme that enables the measurement/control of several nuclear spins (the environment E) interacting with a nitrogen vacancy (the system S). In addition to showing how to create entangled SE states relevant to quantum metrology, we demonstrate that under the decoherence of S, redundant information is imprinted onto E, giving rise to classical objectivity - a consensus of the nuclear spins about the state of S. This provides the first laboratory verification of the objective classical world emerging from the underlying quantum substrate.