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Search Publications by: Stephan Schlamminger (Fed)

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Displaying 51 - 75 of 88

Measurement of the Planck constant at the National Institute of Standards and Technology from 2015 to 2017

July 28, 2017
Author(s)
Darine El Haddad, Frank Seifert, Leon Chao, Antonio Possolo, David B. Newell, Jon R. Pratt, Carl J. Williams, Stephan Schlamminger
Researchers at the National Institute of Standards and Technology(NIST) estimate the value of the Planck constant as h = 6.62606994(10) x 10^-34 Js, hence with relative standard uncertainty 15.3 x 10^-9. This measurement result is based on over 17,000

Sizing up the Quantum

June 2, 2017
Author(s)
Stephan Schlamminger
No abstract. This is a column in Nature science.

Bridging classical and quantum mechanics

September 28, 2016
Author(s)
Darine El Haddad, Frank C. Seifert, Leon S. Chao, Shisong Lee, David B. Newell, Jon R. Pratt, Carl J. Williams, Stephan Schlamminger
Using a watt balance and a frequency comb, a mass-energy equivalence is derived. The 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

Design of a Table-Top Watt Balance

July 26, 2016
Author(s)
Stephan Schlamminger, Jon R. Pratt, David B. Newell, Frank C. Seifert, Michael Liu, Leon S. Chao, Luis Manuel Pea Prez, Shisong Li, Darine El Haddad
Measurements of the Planck constant with watt balances using 1 kg masses have achieved relative standard uncertainties below 2 x 10-8. Having established a metrological link between the kilogram and this fundamental constant of nature, a redefinition of

First mass measurements with the NIST-4 watt balance

July 10, 2016
Author(s)
Darine El Haddad, Leon S. Chao, Frank C. Seifert, David B. Newell, Jon R. Pratt, Stephan Schlamminger
In the past four years, we have constructed a new watt balance at the National Institute of Standards and Technology (NIST), with the goal to realize the unit of mass after the redefinition of the International System of Units, expected to occur in 2018

Improvement of Leakage Resistance of PJVS for NIST-4 Watt Balance Experiment

July 10, 2016
Author(s)
Yi-hua D. Tang, Frank C. Seifert, Stephan Schlamminger
A Programmable Josephson Voltage Standard (PJVS) system is used for the voltage measurements in NIST-4 Watt balance experiment. It is critical to enhance the leakage resistance of the PJVS in order to achieve the uncertainty of voltage measurements better

Quantum Hall Resistance Traceability for the NIST-4 Watt Balance

July 10, 2016
Author(s)
Dean G. Jarrett, Randolph Elmquist, Marlin E. Kraft, George R. Jones Jr., Shamith Payagala, Frank Seifert, Stephan Schlamminger, Darine El Haddad
Scaling from the quantum Hall resistance to 100 Ω standard resistors used by the NIST-4 Watt Balance involves multiple resistance standards and bridges to provide the lowest possible uncertainty. Described here is the infrastructure and procedures

A precise instrument to determine the Planck constant, and the future kilogram

June 21, 2016
Author(s)
Darine El Haddad, Frank C. Seifert, Leon S. Chao, David B. Newell, Jon R. Pratt, Carl J. Williams, Stephan Schlamminger, Shisong Li
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

Coil motion effects in watt balances: a theoretical check

February 10, 2016
Author(s)
Stephan Schlamminger, Shisong Li, Darine El Haddad, Frank C. Seifert, Leon S. Chao, Jon R. Pratt
A watt balance is a precision apparatus for the measurement of the Planck constant that has been proposed as a primary method for realizing the unit of mass in a revised International System of Units. In contrast to an ampere balance, which was

Schwere Experimente

November 1, 2015
Author(s)
Stephan Schlamminger, Christian Rothleitner
Obwohl die Standardunsicherheit der Gravitationskonstante in der neuesten Veröffentlichung des CODATA um über die Hälfte reduziert wurde, ist sie noch immer die am ungenauesten bestimmte Naturkonstante.

A LEGO Watt Balance, An apparatus to demonstrate the definition of mass based on the new SI

October 20, 2015
Author(s)
Leon S. Chao, Stephan Schlamminger, David B. Newell, Jon R. Pratt, Georgio A. Sineriz, Frank C. Seifert, Darine El Haddad, Yusi A. Cao, Xiang Zhang
A redefinition of our system of units, the SI, is currently being discussed and its implementation is expected in 2018. With the redefinition, the current base units will no longer be required and all units henceforth will be based upon fixed values of

Recent measurements of the gravitational constant as a function of time

June 11, 2015
Author(s)
Stephan Schlamminger, Jens H. Gundlach, Riley D. Newman
A recent publication (J.D. Anderson et. Al., EPL 110, 1002) found a strong correlation between the measured values of the gravitational constant G and the 5.9-year oscillation of the length of day. Here, we provide a compilation of all published

First measurements of the flux integral with the new NIST-4 watt balance

March 31, 2015
Author(s)
Darine El Haddad, Frank Seifert, Leon Chao, Yusi A. Cao, Georgio A. Sineriz, Jon R. Pratt, David B. Newell, Stephan Schlamminger
In early 2014, construction of a new watt balance, named NIST-4, has started at the National Institute of Standards and Technology (NIST). In a watt balance, similar to a mass comparator, the gravitational force of an unknown mass is compensated by an

A summary of the Planck constant measurements using a watt balance with a superconducting solenoid at NIST

February 5, 2015
Author(s)
Stephan Schlamminger, Richard L. Steiner, Darine El Haddad, David B. Newell, Frank C. Seifert, Leon S. Chao, Ruimin Liu, Edwin R. Williams
Researchers at the National Institute of Standards and Technology have been using a watt balance, NIST-3, to measure the Planck constant h for over ten years. Two recently published values disagree by more than one standard deviation. The motivation for

A determination of the local acceleration of gravity for the NIST-4 watt balance

January 21, 2015
Author(s)
David B. Newell, Eric J. Leaman, Darine El Haddad, Frank C. Seifert, Leon S. Chao, Yusi A. Cao, Jon R. Pratt, Stephan Schlamminger
A new watt balance is being constructed at the National Institute of Standards and Technology in preparation for the redefinition of the International System of Units and the realization of mass through an exact value of the Planck constant. The total

A constant from a mass, a mass from a constant

November 9, 2014
Author(s)
Jon R. Pratt, Stephan Schlamminger, David B. Newell, Leon S. Chao, Zeina J. Kubarych, Patrick J. Abbott, Yusi A. Cao, Frank C. Seifert, Darine El Haddad
NIST recently used a watt balance instrument known as NIST-3 to measure the Planck constant in terms of IPK with a relative uncertainty of approximately 45 parts in 10e9. Along the way to this new NIST value of h, the instrument was also employed to

THE CONSTRUCTION AND CHARACTERIZATION OF THE NIST-4 PERMANENT MAGNET SYSTEM

November 9, 2014
Author(s)
Leon S. Chao, Frank C. Seifert, Shisong Li, Darine El Haddad, Stephan Schlamminger, Jon R. Pratt
A watt balance is an electromagnetic force balancing instrument to realize the unit of mass at the kilogram level. The magnet system is one of the key components. Our group at the National Institute of Standards and Technology is currently building a next

Construction and Performance of the NIST-4 Magnet System

August 24, 2014
Author(s)
Frank C. Seifert, Alireza R. Panna, Leon S. Chao, Yusi A. Cao, Darine El Haddad, Shisong Li, Stephan Schlamminger, Jon R. Pratt, Heeju Choi, Lori Haley
A watt balance is a promising instrument to realize the unit of mass at the kilogram level. The magnet system is one of the key elements of such an instrument. For the new watt balance currently under construction at the National Institute of Standards and

Heterodyne interferometer with subnanometer accuracy

August 24, 2014
Author(s)
Darine El Haddad, Frank C. Seifert, Stephan Schlamminger, Leon S. Chao, David B. Newell, Jon R. Pratt
This paper gives a brief description of the laser interferometer system designed for the next generation watt balance experiment aimed to realize the unit of mass by direct link to Planck constant at the National Institute of Standards and Technology. The

The Design of the NEW NIST-4 Watt Balance

August 24, 2014
Author(s)
Leon S. Chao, Stephan Schlamminger, Frank C. Seifert, Yusi A. Cao, Darine El Haddad, David B. Newell, Jon R. Pratt
The design of the new permanent-magnet driven watt balance and novel mechanical features will demonstrate the high-precision capabilities of a large complex mass measurement system with expected overall uncertainties on the order of 3 parts in 10^8.
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