Institute for Quantum Optics, Ulm University, Albert-Einstein-Allee 11, Ulm 89081, Germany.
Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Phys Rev Lett. 2019 Oct 4;123(14):140402. doi: 10.1103/PhysRevLett.123.140402.
The origin of classical reality in our quantum world is a long-standing mystery. Here, we examine a nitrogen-vacancy center in diamond evolving in the presence of its magnetic nuclear spin environment which is formed by the natural appearance of carbon ^{13}C atoms in the diamond lattice, 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 this process, we implement a novel dynamical decoupling scheme that enables the measurement and control of several nuclear spins (the environment E) interacting with a nitrogen vacancy (the system S). Our experiment demonstrates that, in the course of the decoherence of S, redundant information is indeed imprinted onto E, giving rise to incipient classical objectivity-a consensus recorded in redundant copies, and available from the fragments of the nuclear spin environment E, about the state of S. This provides the first laboratory verification of the process responsible for the emergence of the objective classical world from the underlying quantum substrate.
经典现实在我们量子世界中的起源是一个长期存在的谜团。在这里，我们研究了钻石中的氮空位中心在其磁性核自旋环境中的演化，该环境是由钻石晶格中天然出现的碳 ^{13}C 原子形成的，以研究量子达尔文主义——通过环境在全球范围内传播有关首选量子态的信息的增殖。这种冗余印记的信息解释了客观现实的感知，因为它可以由许多没有干扰感兴趣系统的人独立访问。为了观察这个过程，我们实现了一种新的动态去耦方案，该方案能够测量和控制与氮空位（系统 S）相互作用的几个核自旋（环境 E）。我们的实验表明，在 S 的退相干过程中，冗余信息确实被印刻到 E 上，从而导致初始的经典客观性——在冗余副本中记录的共识，并且可以从核自旋环境 E 的片段中获得，关于 S 的状态。这首次在实验室验证了负责从基础量子衬底中出现客观经典世界的过程。
