Measurement of the total energy of an isolated system by an internal observer

从内部量子参考系视角探讨全局性质的可及性

Accessibility of Global Properties from Internal Quantum Reference Frame Perspectives

研究探讨了从内部量子参考系视角确定系统全局性质的条件，通过扩展方法揭示了不同QRF方法间的关联及根本假设差异。

Extended Wigner's friend problem and the internal consistency of standard quantum mechanics

The extended Wigner's friend problem deals with two Observers each measuring a sealed laboratory in which a friend is making a quantum measurement. We investigate this problem by relying on the basic rules of quantum mechanics as exposed by Feynman in the well-known "Feynman Lectures on Physics". Although recent discussions have suggested that the extended Wigner's friend problem cannot consistently be described by quantum theory, we show here that a straightforward application of these standard rules results in a non-ambiguous and consistent account of the measurement outcomes for all agents …

Non-Inertial Frames in Minkowski Space-Time, Accelerated either Mathematical or Dynamical Observers and Comments on Non-Inertial Relativistic Quantum Mechanics

After a review of the existing theory of non-inertial frames and mathematical observers in Minkowski space-time we give the explicit expression of a family of such frames obtained from the inertial ones by means of point-dependent Lorentz transformations as suggested by the locality principle. These non-inertial frames have non-Euclidean 3-spaces and contain the differentially rotating ones in Euclidean 3-spaces as a subcase. Then we discuss how to replace mathematical accelerated observers with dynamical ones (their world-lines belong to interacting particles in an isolated system) and of how…

Internal time, test clocks and singularity resolution in dust-filled quantum cosmology

The problem of time evolution in quantum cosmology is studied in the context of a dust-filled, spatially flat Friedmann-Robertson-Walker universe. In this model, two versions of the commonly-adopted notion of internal time can be implemented in the same quantization, and are found to yield contradictory views of the same quantum state: with one choice, the big-bang singularity appears to be resolved, but with another choice it does not. This and other considerations lead to the conclusion that the notion of internal time as it is usually implemented has no satisfactory physical interpretation.…

The Leggett-Garg inequality and Page-Wootters mechanism

Violation of the Leggett-Garg inequality (LGI) implies quantum phenomena. In this light we establish that the Moreva \textit{et al.} \cite{moreva} experiment demonstrating the Page-Wootter's mechanism \cite{wootters} falls in the quantum domain. An observer outside a 2-photons world does not detect any change in the $2-$photons state,i.e. there is no time parameter for the outside observer. But an observer attached to one of the photons sees the other photon evolving and this means there is an "internal" time. The LGI is violated for the clock photon whose state evolves with the internal time …

Time from quantum entanglement: an experimental illustration

In the last years several theoretical papers discussed if time can be an emergent property deriving from quantum correlations. Here, to provide an insight into how this phenomenon can occur, we present an experiment that illustrates Page and Wootters' mechanism of "static" time, and Gambini et al. subsequent refinements. A static, entangled state between a clock system and the rest of the universe is perceived as evolving by internal observers that test the correlations between the two subsystems. We implement this mechanism using an entangled state of the polarization of two photons, one of w…

埃弗雷特多世界诠释中作为不可判定命题的量子坍缩

Quantum collapse as undecidable proposition in an Everettian multiverse

本文将量子测量中的波函数坍缩解释为埃弗雷特多世界图景下内部观察者面对的哥德尔式不可判定命题，从而揭示宇宙描述与模拟的根本局限。

世界线固有长度的关联函数

Correlators of Worldline Proper Length

本文证明壳上作用量对世界线质量的导数可计算世界线固有长度关联函数，并提议局部关联函数的对数作为其生成函数，从而从CFT关联函数提取AdS世界线观测量。

关系量子动力学（RQD）：一种信息本体论

Relational Quantum Dynamics (RQD): An Informational Ontology

本文提出关系量子动力学（RQD），以信息关系为本体基础，用语境化关系事实统一解释量子测量、时空涌现与观察者，并回应多项量子基础禁果定理。