Stephan Schlamminger | National Institute of Standards and Technology (original) (raw)

Papers by Stephan Schlamminger

Review of Scientific Instruments, Nov 1, 2017

By many accounts, the Newtonian constant of gravitation G is the fundamental constant that is mos... more By many accounts, the Newtonian constant of gravitation G is the fundamental constant that is most difficult to measure accurately. Over the past three decades, more than a dozen precision measurements of this constant have been performed. However, the scatter of the data points is much larger than the uncertainties assigned to each individual measurement, yielding a Birge ratio of about five. Today, G is known with a relative standard uncertainty of 4.7 × 10 5 , which is several orders of magnitudes greater than the relative uncertainties of other fundamental constants. In this article, various methods to measure G are discussed. A large array of different instruments ranging from the simple torsion balance to the sophisticated atom interferometer can be used to determine G. Some instruments, such as the torsion balance can be used in several different ways. In this article, the advantages and disadvantages of different instruments as well as different methods are discussed. A narrative arc from the historical beginnings of the different methods to their modern implementation is given. Finally, the article ends with a brief overview of the current state of the art and an outlook.

AGU Fall Meeting Abstracts, Dec 1, 2020

Measurement Science and Technology, 1999

A high-precision measurement of the Newtonian gravitational constant G by means of a beam balance... more A high-precision measurement of the Newtonian gravitational constant G by means of a beam balance is being carried out at the University of Zurich. We have made test measurements in which the gravitational force of 103 kg of water was used and G was determined with a relative standard uncertainty of 220 × 10-6. Currently, measurements with 13.5 × 103 kg of mercury are in progress. These measurements are not completed yet, but a preliminary result is presented.

arXiv (Cornell University), Jul 5, 2017

Perhaps the most powerful method for deriving the Newtonian gravitational interaction between two... more Perhaps the most powerful method for deriving the Newtonian gravitational interaction between two masses is the multipole expansion. Once inner multipoles are calculated for a particular shape this shape can be rotated, translated, and even converted to an outer multipole with well established methods. The most difficult stage of the multipole expansion is generating the initial inner multipole moments without resorting to three dimensional numerical integration of complex functions. Previous work has produced expressions for the low degree inner multipoles for certain elementary solids. This work goes further by presenting closed form expressions for all degrees and orders. A combination of these solids, combined with the aforementioned multipole transformations, can be used to model the complex structures often used in precision gravitation experiments.

Nature Physics, Jun 2, 2017

Mapan-journal of Metrology Society of India, Dec 1, 2020

Bulletin of the American …, 2005

The close spacing between the proof mass and the housing in the LISA (Laser Interferometer Space ... more The close spacing between the proof mass and the housing in the LISA (Laser Interferometer Space Antenna) spacecraft has been a concern as there may be spurious feeble forces. Such forces may limit the performance of the gravity wave detector at frequencies below 3 mHz ...

American Astronomical Society Meeting Abstracts, Dec 1, 2006

APS April Meeting Abstracts, May 1, 2004

Review of Scientific Instruments, 2016

A precise instrument, called a watt balance, compares mechanical power measured in terms of the m... more A precise instrument, called a watt balance, compares mechanical power measured in terms of the meter, the second, and the kilogram to electrical power measured in terms of the volt and the ohm. A direct link between mechanical action and the Planck constant is established by the practical realization of the electrical units derived from the Josephson and the quantum Hall effects. We describe in this paper the fourth-generation watt balance at the National Institute of Standards and Technology (NIST), and report our initial determination of the Planck constant obtained from data taken in late 2015 and the beginning of 2016. A comprehensive analysis of the data and the associated uncertainties led to the SI value of the Planck constant, h = 6.626 069 83(22) × 10−34 J s. The relative standard uncertainty associated with this result is 34 × 10−9.

IEEE Transactions on Instrumentation and Measurement

Four terminal-pair air capacitors are important transfer standards to calibrate LCR meters up to ... more Four terminal-pair air capacitors are important transfer standards to calibrate LCR meters up to a frequency of 10 MHz. We report a simple and new method to obtain the frequency dependence of the four terminal-pair capacitance of these standards using a four-channel vector network analyzer (VNA). The frequency dependence of the capacitance of an air capacitor and its uncertainty can be obtained from a single set of measurements without changing connections between the standard and the VNA, as has been the case in previously published work. The calculation of the frequency dependency is straightforward and model-independent. Nevertheless, an elementary model is provided to explain the observed frequency dependence. This article allows every laboratory with a four-channel VNA to measure the frequency dependence of these capacitors. Hence, a significant shortening of the traceability chain is achieved.

Physical Review Letters, Jul 12, 2006

We used a torsion pendulum containing ∼ 9 × 10 22 polarized electrons to search for CP-violating ... more We used a torsion pendulum containing ∼ 9 × 10 22 polarized electrons to search for CP-violating interactions between the pendulum's electrons and unpolarized matter in the laboratory's surroundings or the sun, and to test for preferred-frame effects that would precess the electrons about a direction fixed in inertial space. We find |g e P g N S |/(hc) < 1.7 × 10 −36 and |g e A g N V |/(hc) < 4.8 × 10 −56 for λ > 1AU. Our preferred-frame constraints, interpreted in the Kostelecký framework, set an upper limit on the parameter |b e | ≤ 5.0 × 10 −21 eV that should be compared to the benchmark value m 2 e /M Planck = 2 × 10 −17 eV.

IEEE Transactions on Instrumentation and Measurement, 2023

The United States National Institute of Standards and Technology (NIST) has been developing a new... more The United States National Institute of Standards and Technology (NIST) has been developing a new device for primary standard realization of torque utilizing established traceability to quantum-electrical standards following the 2019 revision of the International system of units (SIs). This device, the Electronic NIST Torque Realizer (ENTR) is a device directly traceable to the quantum-electrical standards of the revised SI with the goal of outperforming current commercial torque transducer uncertainty levels, improving torque tool calibration at low torque ranges, and shortening the torque standards dissemination chain. This project's goal is to create a device for torque calibrations with an operational range of 7 × 10 −4 N m to 1 N m with uncertainty at or below 0.1%. We intend ENTR to be a possible replacement for present transfer standards used in the torque standards dissemination chain, easing the financial and logistical burdens of current torque standards dissemination systems.

arXiv (Cornell University), Jun 8, 2022

The torsion pendulum at the heart of the apparatus to measure the gravitational constant, G at th... more The torsion pendulum at the heart of the apparatus to measure the gravitational constant, G at the Bureau International des Poids et Mesures (BIPM) is used to measure the gravitational torque between source and test-mass assemblies with two methods. In the Cavendish method, the pendulum moves freely. In the electrostatic-servo method, the pendulum is maintained at a constant angle by applying an electrostatic torque equal and opposite to any gravitational torque on the pendulum. The electrostatic torque is generated by a servo. This article describes the design and implementation of this servo at the National Institute of Standards and Technology. We use a digital servo loop with a Kalman filter to achieve measurement performance comparable to the one in an open loop. We show that it is possible to achieve small measurement uncertainty with an experiment that uses three electrodes for feedback control.

A new watt balance is being constructed at National Institute of Standards and Technology (NIST) ... more A new watt balance is being constructed at National Institute of Standards and Technology (NIST) in preparation for the redefinition of the International System of Units and the realization of mass through an exact value of the Planck constant. We describe the procedures used and give results for the measurements of the local acceleration of gravity in the new watt balance facility.

A redefinition of the International System of Units, the SI, is impending and could occur as earl... more A redefinition of the International System of Units, the SI, is impending and could occur as early as 2017. After redefinition, a means to realize the unit of mass is required. A watt balance is a promising device to realize the unit of mass at the kilogram level. At the National Institute of Standards and Technology (NIST), construction of a new watt balance with the sole purpose to realize mass is currently ongoing.