D. E. Krause

Tests of new physics from precise measurements of the Casimir pressure between two gold-coated plates

A micromechanical torsion oscillator has been used to strengthen the limits on new Yukawa forces by determining the Casimir pressure between two gold-coated plates. By significantly reducing the random errors and obtaining the electronic parameters of the gold coatings, we were able to conclusively exclude the predictions of large thermal effects below 1

Evidence of correlations between nuclear decay rates and Earth-Sun distance

\mu

Measurement of the Casimir force between dissimilar metals

m and strengthen the constraints on Yukawa corrections to Newtonian gravity in the interaction range from 29.5 nm to 86 nm.

Improved tests of extra dimensional physics and thermal quantum field theory from new Casimir force measurements

Abstract Unexplained periodic fluctuations in the decay rates of 32 Si and 226 Ra have been reported by groups at Brookhaven National Laboratory ( 32 Si), and at the Physikalisch–Technische–Bundesanstalt in Germany ( 226 Ra). We show from an analysis of the raw data in these experiments that the observed fluctuations are strongly correlated in time, not only with each other, but also with the time of year. We discuss both the possibility that these correlations arise from seasonal influences on the detection system, as well as the suggestion of an annual modulation of the decay rates themselves which vary with Earth–Sun distance.

Constraining New Forces in the Casimir Regime Using the Isoelectronic Technique

The first precise measurement of the Casimir force between dissimilar metals is reported. The attractive force, between a Cu layer evaporated on a microelectromechanical torsional oscillator and an Au layer deposited on an Al2O3 sphere, was measured dynamically with a noise level of 6 fN/sqrt[Hz]. Measurements were performed for separations in the 0.2-2 micro m range. The results agree to better than 1% in the 0.2-0.5 micro m range with a theoretical model that takes into account the finite conductivity and roughness of the two metals. The observed discrepancies, which are much larger than the experimental precision, can be attributed to a lack of a complete characterization of the optical properties of the specific samples used in the experiment.

New constraints on ultrashort-ranged Yukawa interactions from atomic force microscopy ∗

We report new constraints on extra-dimensional models and other physics beyond the standard model based on measurements of the Casimir force between two dissimilar metals for separations in the range

Present status of controversies regarding the thermal Casimir force

0.2\char21{}1.2\ensuremath{\mu}\mathrm{m}.

Application of the proximity force approximation to gravitational and Yukawa-type forces

The Casimir force between a Au-coated sphere and a Cu-coated plate of a microelectromechanical torsional oscillator was measured statically with an absolute error of 0.3 pN. In addition, the Casimir pressure between two parallel plates was determined dynamically with an absolute error of

MEMS-based force sensor: Design and applications

\ensuremath{\approx}0.6\mathrm{mPa}.

Searches for solar-influenced radioactive decay anomalies using spacecraft RTGs

Within the limits of experimental and theoretical errors, the results are in agreement with a theory that takes into account the finite conductivity and roughness of the two metals. The level of agreement between experiment and theory was then used to set limits on the predictions of extra-dimensional physics and thermal quantum field theory. It is shown that two theoretical approaches to the thermal Casimir force which predict effects linear in temperature are ruled out by these experiments. Finally, constraints on Yukawa corrections to Newtons law of gravity are strengthened by more than an order of magnitude in the range 56\char21{}330 nm.