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We demonstrate a distributed atomic clocks network between Shanghai Institute of Optics and fine Mechanics (SIOM) and Shanghai Institute of Measurement and Test (SIMT). The frequency signals from three different clocks transfer in one fiber…

Atomic Physics · Physics 2024-01-10 Jialiang Wang , Deling Zeng , Youzhen Gui , Lian Dong , Rong Wei

The Thermal Time Hypotheis (TTH) has been proposed as a general method for identifying a time variable from within background-free theories which do not come equipped with a pre-defined clock variable. Here, we explore some implications of…

General Relativity and Quantum Cosmology · Physics 2011-08-04 Nicolas C. Menicucci , S. Jay Olson , Gerard J. Milburn

In this paper, a hypothesis that the cosmological gravitational potential can be measured with the use of high-precision atomic clocks is proposed and substantiated. The consideration is made with the use of a quasi-classical description of…

General Physics · Physics 2019-01-03 V. I. Yudin , A. V. Taichenachev

Probing magnetic fields in astrophysical environments is both important and challenging. The Gradient Technique (GT) is a new tool for tracing magnetic fields, rooted in the properties of magnetohydrodynamic (MHD) turbulence and turbulent…

Astrophysics of Galaxies · Physics 2024-06-18 Yue Hu , Alex Lazarian

Real-time time-dependent density functional theory (rt-TDDFT) with hybrid exchange-correlation functional has wide-ranging applications in chemistry and material science simulations. However, it can be thousands of times more expensive than…

Computational Physics · Physics 2019-05-07 Weile Jia , Lin-Wang Wang , Lin Lin

The advent of novel measurement instrumentation can lead to paradigm shifts in scientific research. Optical atomic clocks, due to their unprecedented stability and uncertainty, are already being used to test physical theories and herald a…

Frequency Phase Transfer (FPT) is a technique designed to increase coherence and sensitivity in radio interferometry by making use of the non-dispersive nature of the troposphere to calibrate high-frequency data using solutions derived at a…

We study the possibility of discriminating between metric theories within the Parametrized Post-Newtonian formalism. In this approach, the two-dimensional quantum state of a massive quantum clock becomes, after propagating at low speed and…

General Relativity and Quantum Cosmology · Physics 2026-03-12 F. J. Lobo , M. Rivera-Tapia , G. Rubilar , O. Jiménez , A. Delgado

The large-scale clock network is the key ingredient to obtain high precision in many scenarios, from fundamental research to cutting-edge applications. The advantage of the time synchronization among microwave clocks is their cost, size,…

Optics · Physics 2024-09-20 Ziyang Chen , Dongrui Yu , Ganbin Lu , Yufei Zhang , Song Yu , Bin Luo , Hong Guo

We report preliminary results of a simulation study on the multi-hop extension of the recently-proposed energy-efficient wireless sensor network time synchronization scheme based on time-translating gateways. Unlike the single-hop case, in…

Networking and Internet Architecture · Computer Science 2016-06-30 Qimeng Liao , Kyeong Soo Kim

The relativity of Global Positioning System (GPS) pseudorange measurements is explored within the geometrical optics approximation in the curved space-time near Earth. A space-time grid for navigation is created by the discontinuities…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Thomas B. Bahder

Reliable estimates of Gross Primary Productivity (GPP), crucial for evaluating climate change initiatives, are currently only available from sparsely distributed eddy covariance tower sites. This limitation hampers access to reliable GPP…

Machine Learning · Computer Science 2023-06-27 Rumi Nakagawa , Mary Chau , John Calzaretta , Trevor Keenan , Puya Vahabi , Alberto Todeschini , Maoya Bassiouni , Yanghui Kang

We present a new approach to report in the Section 4 of BIPM Circular T daily values of the offset between UTC and the predictions of UTC broadcast by the GNSS, this quantity we name bUTC_GNSS. In this approach, the determination of UTC -…

Instrumentation and Detectors · Physics 2025-03-06 Pascale Defraigne , Elisa Pinat , Gérard Petit , Frédéric Meynadier

In this paper, we investigate the effect of the strong time-varying transmission distance on the performance of the low-earth orbit (LEO) satellite-terrestrial transmission (STT) system. We propose a new analytical framework using…

Signal Processing · Electrical Eng. & Systems 2022-06-14 Yuanyuan Ma , Tiejun Lv , Tingting Li , Gaofeng Pan , Yunfei Chen , Mohamed-Slim Alouini

This work presents a fully-digital high-accuracy real-time calibration procedure for frequency and time alignment of open-loop wirelessly coordinated coherent distributed antenna array (CDA) modems, enabling radio frequency (RF) phase…

Signal Processing · Electrical Eng. & Systems 2025-12-02 Jason M. Merlo , Samuel Wagner , John Lancaster , Jeffrey A. Nanzer

We report a frequency measurement of the clock transition of a single ^40Ca^+ ion trapped and laser cooled in a miniature ring Paul trap with 10^-15 level uncertainty. In the measurement, we used an optical frequency comb referenced to a…

Atomic Physics · Physics 2015-06-03 Y. Huang , J. Cao , P. Liu , K. Liang , B. Ou , H. Guan , X. Huang , T. Li , K. Gao

The general relativistic gravitomagnetic clock effect consists in the fact that two point particles orbiting a central spinning object along identical, circular equatorial geodesic paths, but in opposite directions, exhibit a time…

General Relativity and Quantum Cosmology · Physics 2007-11-12 Lorenzo Iorio

The comparison of optical reference frequency signals over free-space optical links is limited by the relative motion between local and remote sites. For ground to low earth orbit comparison, the expected Doppler shift and Doppler rate…

Time dilation is a difference in measured time between two clocks that either move with different velocities or experience different gravitational potentials. Both of these effects stem from the theory of relativity and are usually…