Strongly nonlocal unextendible product bases do exist

A set of multipartite orthogonal product states is locally irreducible, if it is not possible to eliminate one or more states from the set by orthogonality-preserving local measurements. An effective way to prove that a set is locally irreducible is to show that only trivial orthogonality-preserving local measurement can be performed to this set. In general, it is difficult to show that such an orthogonality-preserving local measurement must be trivial. In this work, we develop two basic techniques to deal with this problem. Using these techniques, we successfully show the existence of unextendible product bases (UPBs) that are locally irreducible in every bipartition in d⊗d⊗d for any d≥3, and 3⊗3⊗3 achieves the minimum dimension for the existence of such UPBs. These UPBs exhibit the phenomenon of strong quantum nonlocality without entanglement. Our result solves an open question given by Halder et al. [Phys. Rev. Lett. 122, 040403 (2019)] and Yuan et al. [Phys. Rev. A 102, 042228 (2020)]. It also sheds new light on the connections between UPBs and strong quantum nonlocality.

Research on Intelligent Position Posture Detection and Control based on Multi-sensor Fusion Method

Aiming at the problems of low efficiency and high safety risks encountered in grabbing and placing the boxes by manual mode, the multi-sensor fusion method of vision and laser ranging sensor is used for position and posture detection, and the global rough positioning is detected by the global binocular camera. Precise positioning uses four local measurement modules, including a monocular camera and three laser ranging modules, to detect the position and posture of the target, and uses Move it in ROS for trajectory planning, obstacle avoidance detection and object grabbing. The intelligent position posture detection and control technology proposed in this paper can effectively improve the timeliness of the box grabbing operation, ensure the safety of the box grabbing operation, and enhance the adaptability to harsh environments.

Design and calibration of permanent magnet probes for the local measurement of velocity and temperature in a liquid metal backward facing step flow

The simultaneous and local measurement of velocity and the temperature of a non-isothermal liquid metal flow has been an ongoing research topic over decades. The motivation is to obtain a detailed panorama of a liquid metal flow for the validation of turbulent heat flux models. So-called permanent magnet probes were used in the past for the local measurement of velocity and temperature profiles in liquid sodium in rather canonical flow configurations. The next step is to measure velocity and temperature profiles in a more complex flow geometry, namely a vertical confined backward facing step. For this, the permanent magnet probe must be adapted regarding its design, calibration procedure and temperature correction method. Particularly, considering that for this experiment the eutectic alloy of gallium, indium and tin was used as a working fluid, instead of liquid sodium, as in the mentioned past experiments. The main design aspects for a permanent magnet probe found in the literature are summarized and applied to the present probe. A calibration strategy for the probe was developed and implemented for the measurement of mean velocity profiles. A wetting procedure for the probe is proposed. The measured probe sensitivity for all six used probes agrees well with the theoretical estimations. The highest uncertainty contribution to measured sensitivity is related to the typical wetting issues of gallium–indium–tin. Future implementation of permanent magnet probes in general gallium–indium–tin experiments can make use of the developed know-how shared in this work. Graphic abstract

II. Your Present Moment in Spacetime

This essay extends the argument begun in "Why Quantum Mechanics Makes Sense," exploring the conditions under which a physical world can define and communicate information. I argue that like the structure of quantum physics, the principles of Special and General Relativity can be understood as reflecting the requirements of a universe in which things are observable and measurable. I interpret the peculiar hyperbolic structure of spacetime not as the static, four-dimensional geometry of an unobservable "block universe", but as the background metric of an evolving web of communicated information that we, along with all our measuring instruments and recording devices, actually experience in our local "here and now." Our relativistic universe is conceived as a parallel distributed processing system, in which a common objective reality is constantly being woven out of many kinds of facts determined separately in countless local measurement-contexts.

Reproducibility and Instruction Following in the Shop Floor Laboratory Work: The Case of a TMS Experiment

The article addresses the production of reproducibility as a topic that has become acutely relevant in the recent discussions on the replication crisis in science. It brings the ethnomethodological stance on reproducibility into the discussions, claiming that reproducibility is necessarily produced locally, on the shop floor, with methodological guidelines serving as references to already established practices rather than their origins. The article refers to this argument empirically, analyzing how a group of novice neuroscientists performs a series of measurements in a transcranial magnetic stimulation experiment. Based on ethnography and video analysis, the article traces a history of the local measurement procedure invented by the researchers in order to overcome the experimental uncertainty. The article aims to demonstrate (1) how reproducibility of the local procedure is achieved in the shop floor work of the practitioners and (2) how the procedure becomes normalized and questioned as incorrect in the course of experimental practice. It concludes that the difference between guidelines and practical actions is not problematic per se; what may be problematic is that researchers can be engaged in different working projects described by the same instruction.