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Steve K. Lamoreaux

Publications and source records attributed to Steve K. Lamoreaux.

17 recordsLinked to original sources
arXiv2024

Hidden Variables: Rehabilitation of von Neumann's Analysis, and Pauli's Uncashable Check

In his book \textit{The Mathematical Foundations of Quantum Mechanics}, published in 1932, J. von Neumann performed an analysis of the consequences of introducing hidden parameters (hidden variables) into quantum mechanics. He showed that hidden variables cannot be incorporated into the existing theory of quantum mechanics without major modifications, and concluded that if they did exist, the theory would have already failed in situations where it has been successfully applied. von Neumann left open the possibility that the theory is not complete, and his analysis for internal consistency is the best that can be done for a self-referenced logical system (Gödel's theorem). This analysis had been taken as an ``incorrect proof" against the existence of hidden variables. von Neumann's so-called proof isn't even wrong as such a proof does not exist. One of the earliest attempts at a hidden variable theory was by D. Bohm, and because there were no experimental consequences, W. Pauli referred to it as an ``uncashable check." To our knowledge, a successful hidden variable extension to quantum mechanics with testable consequences has not yet been produced, suggesting that von Neumann's analysis is worthy of rehabilitation, which we attempt to provide in a straightforward manner.

quant-ph↗
arXiv2024

Deuterated Polystyrene -- Synthesis and uses for ultracold neutron bottles and the neutron EDM experiment

The synthesis and application of deuterated polystyrene (dps) films is discussed. Ultracold neutron storage properties and the Fermi potential of dps films is measured with the result that Tstore=700 +/- 200 sec for dps in the bottle used and the Fermi potential is about 165neV. The behavior under application of high electric fields in vacuum is measured; the films are sufficiently stable to use in a neutron EDM bottle. Also, the relaxation rate of nuclear spin polarized 199Hg on dps films is measured giving a wall lifetime of 20 sec/cm mean free path, which should make the development of an Hg volume magnetometer possible.

hep-ex↗
arXiv2023

Quantum Sensors for High Energy Physics

Strong motivation for investing in quantum sensing arises from the need to investigate phenomena that are very weakly coupled to the matter and fields well described by the Standard Model. These can be related to the problems of dark matter, dark sectors not necessarily related to dark matter (for example sterile neutrinos), dark energy and gravity, fundamental constants, and problems with the Standard Model itself including the Strong CP problem in QCD. Resulting experimental needs typically involve the measurement of very low energy impulses or low power periodic signals that are normally buried under large backgrounds. This report documents the findings of the 2023 Quantum Sensors for High Energy Physics workshop which identified enabling quantum information science technologies that could be utilized in future particle physics experiments, targeting high energy physics science goals.

hep-ex↗
arXiv2023

On the use of dielectric elements in axion searches with microwave resonant cavities

This study explores the primary effects of dielectric materials in a resonant cavity-based search for axion dark matter. While dielectrics prove beneficial in numerous cases, their incorporation may lead to less-than-optimal performance, especially for the lowest TM mode. Additionally, the stronger confinement of the electric field inside the dielectrics can exacerbate mode mixings, in particular for higher-order modes. Case studies have been carried out using a combination of analytical solutions and numerical simulations. The findings indicate dielectric cavities employing the $\text{TM}_{010}$ mode experience a significant reduction in sensitivity when compared to a similar search conducted in a cavity at equivalent frequency using no dielectrics.

physics.ins-det↗
arXiv2018

Stored Ultracold Neutron Lifetime Experiments: Non-Inertial Frame Effects on the Neutron Velocity Spectrum

Ultracold neutrons (UCN), stored in a cell with hard walls that is attached to, and therefore rotating with, the Earth, will experience non-inertial frame effects, resulting in a broadening of the UCN spectrum. A heating or cooling of the spectrum is also possible. This is because the stored UCN are in a freely falling (inertial) frame between sudden wall collisions, and the acceleration of the cell relative to this frame means that the cell walls will have a new quasi-random velocities between subsequent UCN wall collisions. This results in a random walk of UCN trajectories in momentum space. Estimates of the effects on UCN with specified initial velocities are presented. Although the effects appear as small, they are worth considering for experiments of current interest, and will be important for possible future experiments with anticipated improved accuracy.

physics.ins-det↗
arXiv2014

Stabilizing a Fabry-Perot etalon to 3 cm/s for spectrograph calibration

We present a method of frequency stabilizing a broadband etalon that can serve as a high-precision wavelength calibrator for an Echelle spectrograph. Using a laser to probe the Doppler-free saturated absorption of the rubidium D2 line, we stabilize one etalon transmission peak directly to the rubidium frequency. The rubidium transition is an established frequency standard and has been used to lock lasers to fractional stabilities of $<10^{-12}$, a level of accuracy far exceeding the demands of radial velocity (RV) searches for exoplanets. We describe a simple setup designed specifically for use at an observatory and demonstrate that we can stabilize the etalon peak to a relative precision of $<10^{-10}$; this is equivalent to 3 cm/s RV precision.

astro-ph.IM↗
arXiv2010

Progress in Experimental Measurements of the Surface-Surface Casimir Force: Electrostatic Calibrations and Limitations to Accuracy

Several new experiments have extended studies of the Casimir force into new and interesting regimes. This recent work will be briefly reviewed. With this recent progress, new issues with background electrostatic effects have been uncovered. The myriad of problems associated with both patch potentials and electrostatic calibrations are discussed and the remaining open questions are brought forward.

quant-ph↗
arXiv2008

Computation of Casimir forces for dielectrics or intrinsic semiconductors based on the Boltzmann transport equation

The interaction between drifting carriers and traveling electromagnetic waves is considered within the context of the classical Boltzmann transport equation to compute the Casimir-Lifshitz force between media with small density of charge carriers, including dielectrics and intrinsic semiconductors. We expand upon our previous work [Phys. Rev. Lett. {\bf 101}, 163203 (2008)] and derive in some detail the frequency-dependent reflection amplitudes in this theory and compute the corresponding Casimir free energy for a parallel plate configuration. We critically discuss the the issue of verification of the Nernst theorem of thermodynamics in Casimir physics, and explicity show that our theory satisfies that theorem. Finally, we show how the theory of drifting carriers connects to previous computations of Casimir forces using spatial dispersion for the material boundaries.

quant-ph↗
arXiv2008

Electrostatic Background Forces due to Varying Contact Potentials in Casimir Experiments

The existence of a monotonic distance dependent contact potential between two plates in a Casimir experiment leads to an additional electrostatic force that is significantly different from the case of a constant potential. Such a varying potential can arise if there is a uniform gradient in the work function or contact potential across a plate, as opposed to random microscopic fluctuations associated with patch potentials. A procedure to compensate for this force is described for the case of an experiment where the electrostatic force is minimized at each measurement distance by applying a voltage between the plates. It is noted that the minimizing voltage is not the contact potential.

quant-ph↗
arXiv2008

Contribution of drifting carriers to the Casimir-Lifshitz and Casimir-Polder interactions with semiconductor materials

We develop a new theory for Casimir-Lifshitz and Casimir-Polder interactions with semiconductor surfaces that takes into account charge drift in the bulk material. The corresponding frequency-dependent dispersion relations describe a crossover between Lifshitz results for dielectrics and for good conductors. In the quasi-static limit, our calculated reflection amplitudes coincide with those recently computed to account for Debye screening in the thermal Lifshitz force with conducting surfaces with small density of carriers.

quant-ph↗
arXiv2008

Possible Systematic Effects in Fomblin Coated Storage Cell Neutron Lifetime Measurements

A new neutron lifetime experiment employing frozen Fomblin has produced a result in significant disagreement with previous experiments that used liquid Fomblin near room temperature. This new experiment is subject to very few corrections, so the source of the discrepancy is a mystery. Here we theoretically investigate several possible systematic effects for near-room-temperature storage experiments. By considering the combined effect of gravity with the usual ultracold neutron losses together with surface wave scattering loss and ultracold spectral evoltuion, a correction to a previous neutron lifetime experiment is found to be insignificantly small.

nucl-ex↗
arXiv2008

Possible resolution of the Casimir force finite temperature correction "controversies"

By considering the effect of diffusion on the external electric field response of charge carriers in metals and semiconductors, it is shown that the finite temperature correction proposed Bostrom and Sernelius requires substantial modification, and there is no large correction as suggested for good conductors. The apparent violation of the Third Law of Thermodynamics of the various proposed temperature corrections to the Casimir force is also resolved. Finally, the effect of Debye screening on electrostatic calibrations between pure germanium surfaces is calculated

quant-ph↗
arXiv2007

Gadolinium Iron Garnet as a Solid State Material for an Electron Electric Dipole Moment Search

The possibility of a solid state electron electric dipole moment (EDM) experiment based on Gadolinium Iron Garnet (GdIG) is investigated. GdIG appears to exhibit superparamagnetism and this effect can be used to enhance the electric-field-induced EDM signal at relatively a high temperatures, as compared to a simple paramagnetic system such as Gadolinium Gallium Garnet. The sensitivity of a GdIG based experiment might be large enough that an improvement by over three orders of magnitude, compared to the existing electron EDM limit, could be obtained at a modest temperature of 4 K, assuming that the superparamagnetic effect is not suppressed at this temperature, and that the spin relaxation time remains sufficiently rapid.

physics.atom-ph↗
arXiv2001

Comment on "Thermal Effects on the Casimir Force in the 0.1-5 micrometer Range"

In a recent paper (M. Bostrom and Bo E. Sernelius, Phys. Rev. Lett. 84, 4757 (2000)) the combined effect of finite conductivity and finite temperature on the Casimir force is analyzed, and significant deviations from other theoretical results and a recent experiment are obtained. In this Comment, I show that the extrapolation to zero frequency is incorrect because the authors have neglected that the wavenumber and frequency of the electromagentic mode must simultaneously appraoch zero

quant-ph↗
arXiv1999

Practical quantum cryptography for secure free-space communications

Quantum cryptography is an emerging technology in which two parties may simultaneously generate shared, secret cryptographic key material using the transmission of quantum states of light. The security of these transmissions is based on the inviolability of the laws of quantum mechanics and information-theoretically secure post-processing methods. An adversary can neither successfully tap the quantum transmissions, nor evade detection, owing to Heisenberg's uncertainty principle. In this paper we describe the theory of quantum cryptography, and the most recent results from our experimental free-space system with which we have demonstrated for the first time the feasibility of quantum key generation over a point-to-point outdoor atmospheric path in daylight. We achieved a transmission distance of 0.5 km, which was limited only by the length of the test range. Our results provide strong evidence that cryptographic key material could be generated on demand between a ground station and a satellite (or between two satellites), allowing a satellite to be securely re-keyed on orbit. We present a feasibility analysis of surface-to-satellite quantum key generation.

quant-ph↗