Vienna Center for Quantum Science and Technology (VCQ), Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090, Vienna, Austria.
Institute of Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, Boltzmanngasse 3, A-1090, Vienna, Austria.
Nat Commun. 2019 Jan 30;10(1):494. doi: 10.1038/s41467-018-08155-0.
In physics, every observation is made with respect to a frame of reference. Although reference frames are usually not considered as degrees of freedom, in all practical situations it is a physical system which constitutes a reference frame. Can a quantum system be considered as a reference frame and, if so, which description would it give of the world? Here, we introduce a general method to quantise reference frame transformations, which generalises the usual reference frame transformation to a "superposition of coordinate transformations". We describe states, measurement, and dynamical evolution in different quantum reference frames, without appealing to an external, absolute reference frame, and find that entanglement and superposition are frame-dependent features. The transformation also leads to a generalisation of the notion of covariance of dynamical physical laws, to an extension of the weak equivalence principle, and to the possibility of defining the rest frame of a quantum system.
在物理学中，每一次观测都是相对于参考系进行的。虽然参考系通常不被视为自由度，但在所有实际情况下，构成参考系的都是物理系统。量子系统能否被视为参考系，如果可以，它会对世界给出怎样的描述？在这里，我们引入了一种量化参考系变换的通用方法，它将通常的参考系变换推广为“坐标变换的叠加”。我们在不同的量子参考系中描述状态、测量和动力学演化，而不诉诸于外部的、绝对的参考系，并发现纠缠和叠加是与参考系相关的特征。这种变换还导致了对动力学物理定律协变性概念的推广，对弱等效原理的扩展，以及定义量子系统的静止参考系的可能性。
