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Search Publications by: Neil Ashby (Assoc)

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Displaying 1 - 25 of 102

A relativistic framework to establish Coordinate time on the Moon and Beyond

February 17, 2024
Author(s)
Neil Ashby, Bijunath Patla
The rate of clocks, according to Einstein's theory of relativity, is influenced by the gravitational potential and relative motion of the clocks. A grid of synchronized clocks that is traceable to an ideal clock at a predetermined point in space is the

Comparison of Open and Solid Falling Retroreflector Gravimeters

May 29, 2020
Author(s)
Neil Ashby, Derek Van Westrum
We study whether the optical properties of a solid glass retroreflector influence the value of the acceleration of gravity $g$ determined by dropping both solid and open retroreflectors in an absolute ballistic gravimeter. The retroreflectors have

Reply to comment on "Relativistic Theory of the Falling Cube Gravimeter"

March 14, 2018
Author(s)
Neil Ashby
The comment\cite{kren17} claims that the paper Relativistic theory of the falling cube gravimeter \cite{ashby17} is incorrect. The authors of this comment assert that optical paths in the two interferometer arms of an absolute gravimeter shift only the

Incorporating an Optical Clock into a Time Scale

January 1, 2018
Author(s)
Jian Yao, Thomas E. Parker, Neil Ashby, Judah Levine
This paper discusses how to build a time scale with an intermittently-operated optical clock. In particular, it gives suggestions on how long and how often to run an optical clock. It also explores the benefits of having an optical clock in a time scale

Relativistic theory of the falling retroreflector gravimeter

December 12, 2017
Author(s)
Neil Ashby
We develop a relativistic treatment of interference between light reflected from a falling cube retroreflector in the vertical arm of an interferometer, and light in a reference beam in the horizontal arm. Coordinates that are nearly Minkowskian, attached

Confidence Estimates in Simulation of Phase Noise or Spectral Density

March 8, 2017
Author(s)
Neil Ashby
In this paper we apply the method of discrete simulation of power law noise, developed in [1,2], to simulation of phase noise for a combination of power law noises. We derive the probability of observing a value of phase noise L(f) or of any of the one

Measurement of the Microwave Lensing Shift in NIST-F1 and NIST-F2

October 12, 2015
Author(s)
Steven R. Jefferts, Stephan E. Barlow, Thomas P. Heavner, Neil Ashby
We present measurements of the microwave lensing frequency shift in the Primary Frequency Standards (PFS) NIST-F1 and NIST-F2. This frequency bias is reasonably controversial with differing theories giving quite different results. Our measurements are in

Precision measurement of the speed of propagation of neutrinos using the MINOS detectors

September 17, 2015
Author(s)
Stefania Romisch, P Adamson, I Anghel, Neil Ashby, A Aurisano, G. Barr, M. Bishai, A. Blake, C. M. Castromonte, S. Childress, M. Christensen, J. A. Coelho, L. Corwin, D. Cronin-Hennessy, J. K. de Jong, A. V. Devan, N. E. Devenish, M. V. Diwan, C. O. Escobar, J. J. Evans, E. Falk, G. J. Feldman, Blair Fonville, M. V. Frohne, H. R. Gallagher, R. A. Gomes, M. C. Goodman, P. Gouffon, N. Graf, R. Gran, K. Grzelak, A. Habig, S. R. Hahn, J. Hartnell, R. Hatcher, Jonathan Hirschauer, A. Holin, J. Huang, J. Hylen, G M. Irwin, Z. isvan, C. James, Steven R. Jefferts, D. Jensen, T. Kafka, S. M. Kasahara, G. Koizumi, M. Kordosky, A. Kreymer, K. Lang, J. Ling, P. J. Litchfield, P. Lucas, W. A. Mann, M. L. Marshak, Demetrios Matsakis, N. Mayer, Angela Mckinley, C. McGivern, M. M. Medeiros, R. Mehdiyev, J Meier, M. D. Messier, W. H. Miller, S. R. Mishra, Stephen Mitchell, S. Moed Sher, C. D. Moore, L. Mualem, J. A. Musser, D. Naples, J. K. Nelson, H. Newman, R. J. Nichol, J. A. Nowak, J. C. O'Conner, M. Orchanian, R. B. Pahlka, J. Paley, Thomas E. Parker, R. B. Patterson, G. Pawloski, A. Perch, S. Phan-Budd, R. K. Plunkett, N. Poonthattatil, Ed Powers, X. Qiu, A. Radovick, B. Rebel, K. Ridl, C. Rosenfeld, H. A. Rubin, M. C. Sanchez, J. Schneps, A. Schreckenberger, P. Schreiner, R. Sharma, A, Sousa, N. Tagg, R, L. Talaga, J. Thomas, M. A. Thomson, X. Tian, A. Timmons, S. C. Tognini, R. Toner, D. Torretta, J. Urheim, P. Vahle, B. Viren, A. Weber, R. C. Webb, C. White, L. Whitehead, L. H. Whitehead, S. G. Wojcicki, J. Wright, Victor S. Zhang, R. Zwaska
We report a two-detector measurement of the propagation speed of neutrinos over a baseline of 734 km. The measurement was made with the NuMI beam at Fermilab between the near and far MINOS detectors. The fractional difference between the neutrino speed and