scholarly journals Quantum test of the Universality of Free Fall using rubidium and potassium

2020 ◽  
Vol 74 (7) ◽  
Author(s):  
Henning Albers ◽  
Alexander Herbst ◽  
Logan L. Richardson ◽  
Hendrik Heine ◽  
Dipankar Nath ◽  
...  
Keyword(s):  
Free Fall ◽  
Standard Uncertainty ◽  
Matter Wave ◽  
Universality Of Free Fall ◽  
Systematic Effects

Abstract We report on an improved test of the Universality of Free Fall using a rubidium-potassium dual-species matter wave interferometer. We describe our apparatus and detail challenges and solutions relevant when operating a potassium interferometer, as well as systematic effects affecting our measurement. Our determination of the Eötvös ratio yields ηRb,K = −1.9 × 10−7 with a combined standard uncertainty of ση = 3.2 × 10−7. Graphical abstract

scholarly journals Ultracold atom interferometry in space

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Maike D. Lachmann ◽  
Holger Ahlers ◽  
Dennis Becker ◽  
Aline N. Dinkelaker ◽  
Jens Grosse ◽  
...  
Keyword(s):  
Spatial Coherence ◽  
Free Fall ◽  
Atom Interferometry ◽  
Matter Wave ◽  
Sounding Rocket ◽  
Ultracold Atom ◽  
Fundamental Physics ◽  
Light Pulses ◽  
Bose Einstein ◽  
Promising Source

AbstractBose-Einstein condensates (BECs) in free fall constitute a promising source for space-borne interferometry. Indeed, BECs enjoy a slowly expanding wave function, display a large spatial coherence and can be engineered and probed by optical techniques. Here we explore matter-wave fringes of multiple spinor components of a BEC released in free fall employing light-pulses to drive Bragg processes and induce phase imprinting on a sounding rocket. The prevailing microgravity played a crucial role in the observation of these interferences which not only reveal the spatial coherence of the condensates but also allow us to measure differential forces. Our work marks the beginning of matter-wave interferometry in space with future applications in fundamental physics, navigation and earth observation.

Determination of Mean Free Path for Inelastic Scattering in Poly(2-Vinyl Pyridine) by Low-Loss Spectrum Imaging

2000 ◽  
Vol 6 (S2) ◽  
pp. 224-225
Author(s):  
A. Aitouchen ◽  
T. Chou ◽  
M. Libera ◽  
M. Misra
Keyword(s):  
Free Path ◽  
Free Fall ◽  
Mean Free Path ◽  
Specimen Thickness ◽  
Thickness Determination ◽  
Vinyl Pyridine ◽  
Integrated Intensity ◽  
Inelastic Mean Free Path ◽  
Electron Energy Loss

The common experimental method to determine the total inelastic mean free path i by electron energy-loss spectroscopy (EELS) is by the relation : t/λi= ln(It/IO) [1] where t is the specimen thickness, It, is the total integrated intensity, and Io is the intensity of the zero-loss peak. The accuracy of this measurement depends on the thickness determination. Model geometries like cubes, wedges, and spheres enable accurate thickness determination from transmission images.Spherical polymers with diameters of order 10-200nm can be made from a number of high-Tg polymers by solvent atomization. This research studied atomized spheres of poly(2-vinyl pyridine) [PVP]. A solution of 0.1% PVP in THF was nebulized. After solvent evaporation during free fall within the chamber atmosphere, solid spherical polymer particles with a range of diameters were collected on holey-carbon TEM grids at the bottom of the atomization chamber.

TO THE CALCULATION OF LENGTH OF GEOPHYSICAL OBJECTS OF HYPERBOLIC OUTLINE

2021 ◽  
pp. 85-89
Author(s):  
K. N. ANAKHAEV ◽  
◽  
B. KH. AMSHOKOV ◽  
K. K. ANAKHAEV
Keyword(s):  
Water Management ◽  
Applied Research ◽  
Free Fall ◽  
Linear Interpolation ◽  
Close Approximation ◽  
Tabular Data ◽  
Exact Determination ◽  
Complex Dependence ◽  
Incomplete Elliptic Integrals

Hyperbolic curves are used in various theoretical and practical studies, including in the field of water management and environmental construction when calculating various geophysical objects with hyperbolic outlines (surfaces of coastal slopes, sliding lines of landslide massifs, directing dams, spillway surfaces of watersheds, water free fall trajectories, etc.). The exact determination of the length of the hyperbola arc is represented by a rather complex dependence based on “unbreakable” incomplete elliptic integrals, which makes it difficult to carry out analytical calculations and involves the use of tabular data with a time-consuming cross and non-linear interpolation of them, etc. Elementary dependencies are proposed to determine the length of the hyperbola arc, which give a very close approximation (up to 1%) to exact values. The obtained calculated analytical dependencies for determining the length of the hyperbola arc are recommended for practical use in theoretical and applied research in various fi elds of science and technology.

scholarly journals The NIST Johnson Noise Thermometry System for the Determination of the Boltzmann Constant

2017 ◽  
Vol 122 ◽  
Author(s):  
Nathan E. Flowers-Jacobs ◽  
Alessio Pollarolo ◽  
Kevin J. Coakley ◽  
Adam C. Weis ◽  
Anna E. Fox ◽  
...  
Keyword(s):  
International System ◽  
Standard Uncertainty ◽  
Boltzmann Constant ◽  
Correlated Noise ◽  
Johnson Noise ◽  
Noise Thermometry ◽  
Relative Standard ◽  
System Of Units ◽  
Johnson Noise Thermometry

In preparation for the redefinition of the International System of Units (SI), five different electronic measurements of the Boltzmann constant have been performed using different Johnson noise thermometry (JNT) systems over the past seven years. In this paper, we describe in detail the JNT system and uncertainty components associated with the most recent National Institute of Standards and Technology (NIST) determination of the Boltzmann constant: k = 1.380642 9(69) × 10−23 J/K, with a relative standard uncertainty of 5.0 × 10−6 and relative offset of −4.05 × 10−6 from the Committee on Data for Science and Technology (CODATA) 2014 recommended value. We discuss the input circuits and the approach we used to match the frequency response of two noise sources. We present new measurements of the correlated noise of the 4 K on-chip resistors in the quantum-accurate, pseudorandom, voltage-noise source, which we used to estimate the correlated, frequency-dependent, nonthermal noise in our system. Finally, we contrast our system with those used in other measurements and speculate on future improvements.

scholarly journals Why direct and post-refinement determinations of absolute structure may give different results

2016 ◽  
Vol 72 (5) ◽  
pp. 661-683 ◽  
Author(s):  
David John Watkin ◽  
Richard Ian Cooper
Keyword(s):  
Recent Literature ◽  
Structure Refinement ◽  
Direct Determination ◽  
Standard Uncertainty ◽  
Data Sets ◽  
Normal Probability Plot ◽  
Normal Probability ◽  
Structure Determinations ◽  
Absolute Structure

Direct determination of the Flack parameter as part of the structure refinement procedure usually gives different, though similar, values to post-refinement methods. The source of this discrepancy has been probed by analysing a range of data sets taken from the recent literature. Most significantly, it was observed that the directly refined Flack (x) parameter and its standard uncertainty are usually not much influenced by changes in the refinement weighting schemes, but if they are then there are probably problems with the data or model. Post-refinement analyses give Flack parameters strongly influenced by the choice of weights. Weights derived from those used in the main least squares lead to post-refinement estimates of the Flack parameters and their standard uncertainties very similar to those obtained by direct refinement. Weights derived from the variances of the observed structure amplitudes are more appropriate and often yield post-refinement Flack parameters similar to those from direct refinement, but always with lower standard uncertainties. Substantial disagreement between direct and post-refinement determinations are strongly indicative of problems with the data, which may be difficult to identify. Examples drawn from 28 structure determinations are provided showing a range of different underlying problems. It seems likely that post-refinement methods taking into account the slope of the normal probability plot are currently the most robust estimators of absolute structure and should be reported along with the directly refined values.

Research on Mass Determination of International Comparison CCM.M-K4 of 1 kg Mass Weights

2015 ◽  
Vol 742 ◽  
pp. 75-79
Author(s):  
Man Hong Hu ◽  
Jian Wang ◽  
Yue Zhang ◽  
Chang Qing Cai ◽  
Rui Lin Zhong ◽  
...  
Keyword(s):  
International Comparison ◽  
Process Analysis ◽  
Mass Difference ◽  
Standard Uncertainty ◽  
Measurement Process ◽  
Mass Determination ◽  
Average Mass ◽  
Test Standards

CCM.M-K4 is a key international comparison organized by the Bureau International des Poids et Mesures (BIPM) to verify the measurement ability of 1kg stainless weights. This paper reports the process analysis of mass determination of CCM.M-K4 during the measurement in NIM, China. The gravity correction and air bouncy correction are discussed, and the measuring uncertainties of measurement process are evaluated. Mass difference between the test standards is 0.0015 mg, and average mass of both test standards is 0.013 mg. The standard uncertainty of test weights is 0.013 mg.

scholarly journals Modified Method of Krejnin and Murri for the Determination of Absolute Declinations

1990 ◽  
Vol 141 ◽  
pp. 95-95
Author(s):  
S.A. Tolchelnikova-Murri
Keyword(s):  
Equatorial Zone ◽  
Micrometer Screw ◽  
Modified Method ◽  
Scale Error ◽  
Systematic Effects ◽  
Global Reduction ◽  
Improve Planning

Krejnin and Muni's method (1973) enablesenables one to derive absolute declinations of stars in a narrow equatorial zone |δ| < 10′ from observations near the Earth's equator |ϕ| < 10′. Some systematic effects, including the errors of the value of the micrometer screw for two equatorial instruments (or the scale error if one of the instruments is a PZT), might be determined if a global reduction is used for the original observations from the equator and from those of an astrolabe at latitude |ϕ| ∼ 20° to 23°. Astrolabes—especially photoelectric ones (Hu 1988) are considered to be the most efficient for determination of absolute declinations of stars and absolute latitudes of the instruments in Tolchel'nikova-Murri (1985).In Izv. GAO No. 206 the method will be published as well as the criterion for estimating the efficiency of different programs, which is required to improve planning in astrometry.

Sign in / Sign up

Export Citation Format

Share Document