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We propose a new method to reduce the frequency noise of a Local Oscillator (LO) to the level of white phase noise by maintaining (not destroying by projective measurement) the coherence of the ensemble pseudo-spin of atoms over many…

Atomic Physics · Physics 2014-07-24 Nobuyasu Shiga , Makoto Takeuchi

Considering the OPERA neutrino-velocity measurement from the point of view of a GPS satellite we find that the detector at Gran Sasso has a velocity component in the order of $10^{-5}c$ towards the neutrino emission location at CERN. On…

General Physics · Physics 2011-11-22 Ronald A. J. van Elburg

Improvements in atom-light coherence are foundational to progress in quantum information science, quantum optics, and precision metrology. Optical atomic clocks require local oscillators with exceptional optical coherence due to the…

The approaches to searching for axion-like signals based on pulsars include observations with pulsar timing arrays (PTAs) and pulsar polarization arrays (PPAs). However, these methods are limited by observational uncertainties arising from…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-24 Hanyu Jiang , Baoyu Xu , Yun-Long Zhang

This paper addresses the motivation, technology and recent results in the tests of the general theory of relativity (GR) in the solar system. We specifically discuss Lunar Laser Ranging (LLR), the only technique available to test the Strong…

General Relativity and Quantum Cosmology · Physics 2017-08-23 Slava G. Turyshev , James G. Williams , Kenneth Nordtvedt , Michael Shao , Thomas W. Murphy

In optical clocks, transitions of ions or neutral atoms are interrogated using pulsed ultra-narrow laser fields. Systematic phase chirps of the laser or changes of the optical path length during the measurement cause a shift of the…

Atomic Physics · Physics 2012-08-10 Stephan Falke , Mattias Misera , Uwe Sterr , Christian Lisdat

We present the frequency stability performances of a vapor cell Rb clock based on the pulsed optically pumping (POP) technique. The clock has been developed in the frame of a collaboration between INRIM and Leonardo SpA, aiming to realize a…

The passive retroreflector arrays placed on the moon by Apollo 11, 14 and 15 astronauts continue to produce valuable Earth-Moon range measurements that enable high-precision tests of gravitational physics, as well as studies of geo- and…

Instrumentation and Methods for Astrophysics · Physics 2024-05-20 Sanchit Sabhlok , James B. R. Battat , Nicholas R. Colmenares , Daniel P. Gonzales , Thomas W. Murphy

A high performance Space-Time Reference in orbit could be realized using a stable atomic clock in a precisely defined orbit and linking that to high accuracy atomic clocks on the ground using a laser based time-transfer link. This would…

Optics · Physics 2017-08-23 Paul Berceau , Leo Hollberg

The response of the Advanced LIGO interferometers is known to vary with time [arXiv:1608.05134]. Accurate calibration of the interferometers must therefore track and compensate for temporal variations in calibration model parameters. These…

Instrumentation and Methods for Astrophysics · Physics 2023-01-11 Madeline Wade , Aaron D. Viets , Theresa Chmiel , Madeline Stover , Leslie Wade

Lunar laser ranging has provided many of the best tests of gravitation since the first Apollo astronauts landed on the Moon. The march to higher precision continues to this day, now entering the millimeter regime, and promising continued…

General Relativity and Quantum Cosmology · Physics 2013-09-25 T. W. Murphy

Precision timekeeping is fundamental to modern technologies such as Global Navigation Satellite Systems (GNSS), communication networks, financial transactions, and power grid management. Over the past 50 years, microwave atomic clocks have…

Atomic Physics · Physics 2025-07-15 Benjamin White , Rachel Offer , Ashby Hilton , Andre Luiten

Precise measurements of the Earth-Moon distance by the lunar laser ranging (LLR), which begun in the early 1970's, contributed significantly to geodesy, geophysics, and lunar planetology, as well as enabled astrophysicists to perform…

Astrophysics · Physics 2009-11-07 Yu. V. Dumin

We have continued our effort to re-reduce archival Q0957+561 brightness monitoring data and present results for 1629 R-band images using the methods for galaxy subtraction and seeing correction reported previously. The new dataset comes…

Astrophysics · Physics 2009-10-31 Wesley N. Colley , Rudolph E. Schild

We provide an analysis of timing irregularities observed for 366 pulsars. Observations were obtained using the 76-m Lovell radio telescope at the Jodrell Bank Observatory over the past 36 years. These data sets have allowed us to carry out…

Astrophysics of Galaxies · Physics 2015-05-14 G. Hobbs , A. G. Lyne , M. Kramer

This paper describes advances in microwave frequency standards using laser-cooled atoms at BNM-SYRTE. First, recent improvements of the $^{133}$Cs and $^{87}$Rb atomic fountains are described. Thanks to the routine use of a cryogenic…

This paper describes the Light-Shift Laser-Lock (LSLL) technique, a novel method intended for compact atomic clocks that greatly simplifies the laser setup by stabilizing the pumping-laser frequency to the atoms involved in the clock,…

Atomic Physics · Physics 2024-04-23 Claudio E. Calosso , Michele Gozzelino , Filippo Levi , Salvatore Micalizio

The measurement error of pulse times of arrival (TOAs) in the high S/N limit is dominated by the quasi-random variation of a pulsar's emission profile from rotation to rotation. Like measurement noise, this noise is only reduced as the…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 Matthew Kerr

We used Precise Point Positioning, a well-established GPS carrier-phase frequency transfer method to perform a direct remote comparison of two optical frequency standards based on single laser-cooled $^{171}$Yb$^+$ ions operated at NPL, UK…

The revision of the standard Los Alamos opacities in the 1980-1990s by a group from the Lawrence Livermore National Laboratory (OPAL) and the Opacity Project (OP) consortium was an early example of collaborative big-data science, leading to…

Solar and Stellar Astrophysics · Physics 2018-05-22 Claudio Mendoza