A micromechanical torsion oscillator has been used to strengthen the limits on new Yukawa forces by determining Casimir pressure between two gold-coated plates. By significantly reducing random errors and obtaining electronic parameters of gold coatings, we were able conclusively exclude predictions large thermal effects below $1\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ constraints corrections Newtonian gravity in interaction range from 29.5 nm 86 nm.

The first precise measurement of the Casimir force between dissimilar metals is reported. attractive force, a Cu layer evaporated on microelectromechanical torsional oscillator, and an Au deposited Al$_2$O$_3$ sphere, was measured dynamically with noise level 6 fN/$\sqrt{\rm{Hz}}$. Measurements were performed for separations in 0.2-2 $\mu$m range. results agree to better than 1% 0.2-0.5 range theoretical model that takes into account finite conductivity roughness two metals. observed...

We report new constraints on extra-dimensional models and other physics beyond the standard model based measurements of Casimir force between two dissimilar metals for separations in range $0.2--1.2\ensuremath{\mu}\mathrm{m}.$ The a Au-coated sphere Cu-coated plate microelectromechanical torsional oscillator was measured statically with an absolute error 0.3 pN. In addition, pressure parallel plates determined dynamically $\ensuremath{\approx}0.6\mathrm{mPa}.$ Within limits experimental...

We report the first isoelectronic differential force measurements between an Au-coated probe and two films, made out of Au Ge. These measurements, performed at submicron separations using soft microelectromechanical torsional oscillators, eliminate need for a detailed understanding probe-film Casimir interaction. The observed signal is directly converted into limits on parameters $\ensuremath{\alpha}$ $\ensuremath{\lambda}$ which characterize Yukawa-like deviations from Newtonian gravity....

The electric-dipole moment (edm) of the ground state cesium has been measured using a two-laser method that does not require presence an external B field. value ${\mathit{d}}_{\mathrm{Cs}}$=(-1.8\ifmmode\pm\else\textpm\fi{}6.7\ifmmode\pm\else\textpm\fi{}1.8)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}24}$ e cm implies electron EDM is...

We report the results of new differential force measurements between a test mass and rotating source masses gold silicon to search for forces beyond Newtonian gravity at short separations. The technique employed subtracts otherwise dominant Casimir outset and, when combined with lock-in amplification technique, leads significant improvement (up factor $10^{3}$) over existing limits on strength (relative gravity) putative in 40--8000 nm interaction range.

The relative frequency of Hg and Cs mgnetometers is monitored as a function the orientation applied magnetic field with respect to fixed stars. observed stability limits electron nucleon local Lorentz invariance violating effects less than 200 \ensuremath{\mu}Hz 110 nHz, respectively. These results represent an improvement over best published by order magnitude for factor 240 nuclear effects. result also sets upper limit eV on Fermi level degenerate remnant neutrino background.

The analysis of all Casimir force experiments using a sphere-plate geometry requires the use proximity-force approximation (PFA) to relate between sphere and flat plate energy two parallel plates. Because it has been difficult assess PFA's range applicability theoretically, we have conducted an experimental search for corrections PFA by measuring gradient gold-coated five spheres with different radii microelectromechanical torsion oscillator. For separations z<300 nm, find that magnitude...

Many extensions to the standard model lead possibility of new forces which would produce Yukawa corrections Newtonian gravity. Models in gravitational and gauge interactions are unified at $\ensuremath{\sim}1\mathrm{TeV}$ using large extra dimensions could Yukawa-type law submillimeter distances. In some models with $n=3$ dimensions, deviations from gravity occur separations $\ensuremath{\sim}5\mathrm{nm},$ a distance scale accessible an atomic force microscope (AFM). Here we present...

We point out the potential of diatomic molecule PbO as a system in which to search for an electron electric dipole moment (EDM). Large oscillator strengths between various electronic states would be beneficial such experiment. As step toward determining these strengths, we have measured number radiative lifetimes and branching ratios PbO. discuss impact our measurements on proposed EDM experiment need further experimental theoretical work

We compare the relative precession frequencies of Hg and Cs magnetometers as a function position two 475 kg lead masses with respect to an applied magnetic field. Our observations limit size possible monopole-dipole interaction expected be produced by pseudoscalar particle such axion. For range 20 cm, products scalar couplings $({g}_{s}{g}_{p}/\ensuremath{\Elzxh}c)$ are found less than $2.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}29}$...

Recently Kim et al. [Phys. Rev. A 78, 020101(R) (2008)] performed electrostatic calibrations for a plane plate above centimeter-size spherical lens at separations down to 20--30 nm and observed ``anomalous behavior.'' It was found that the gradient of force does not depend on separation as predicted basis pure Coulomb contribution. Some hypotheses which could potentially explain deviation from expected behavior were considered, qualitative arguments in favor influence patch surface...

The precise measurement of weak effects plays a pivotal role in metrology and the determination fundamental constants. Hence, possibility new forces, related question non-Newtonian behaviour gravitational force, have been special interest to both scientists those involved tests physical laws. To date there is no compelling evidence for any deviations from predictions Newtonian gravity nonrelativistic weak-field regime. A significant literature on this has developed over past few years, host...

We have performed a precise experimental determination of the Casimir pressure between two gold-coated parallel plates by means micromachined oscillator. In contrast to all previous experiments on effect, where small relative error (varying from 1% 15%) was achieved only at shortest separation, our smallest (~ 0.5%) is over wide separation range 170 nm 300 95% confidence. formulated rigorous metrological procedure for comparison experiment and theory without resorting previously used...

We apply the proximity force approximation, which is widely used for calculation of Casimir between bodies with nonplanar boundary surfaces, to gravitational and Yukawa-type interactions. It shown that in a sphere-plate configuration general formulation approximation well applicable. For interaction we demonstrate validity both simple mapping plate-plate configurations. The claims contrary some recent literature are thus incorrect. Our results justify constraints on parameters non-Newtonian...

A new method for the detection of electron edm using a solid is described. The involves measurement voltage induced across by alignment samples magnetic dipoles in an applied field, H. first application to GdIG has resulted limit on 5E-24 e-cm, which factor 40 below obtained from only previous solid-state experiment. result limited imperfect discrimination unexpectedly large that even upon reversal sample magnetization.

It is well known that, beginning in 2000, the behavior of thermal correction to Casimir force between real metals has been hotly debated.As was shown by several research groups, Lifshitz theory, which provides theoretical foundation for calculation both van der Waals and forces, leads different results depending on model metal conductivity used.To resolve these controversies, considerations based principles thermodynamics new experimental tests were invoked.We analyze present status problem...

We discuss theoretical predictions for the thermal Casimir force and compare them with available experimental data. Special attention is paid to recent claim of observation that effect, as predicted by Drude model approach. show this in contradiction a number experiments reported so far. suggest errors, support force, are significantly underestimated. Furthermore, data at separations above 3μm shown be agreement not approach, claimed, but plasma model. The seeming below 3 μm explained use an...