arXiv subjects

M. T. Ziemba

Publications and source records attributed to M. T. Ziemba.

3 recordsLinked to original sources

arXiv2026

Spin interferometry in a beam of ultracold molecules

We describe a spin interferometer using ultracold YbF molecules and develop the complete set of techniques needed to measure the electron's electric dipole moment, $d_e$, with this apparatus. The molecules are cooled in an optical molasses and prepared in a single internal quantum state. A Raman transition prepares a spin superposition which evolves in parallel magnetic and electric fields before a second Raman transition maps the phase onto the populations of two hyperfine states. These populations are read out using detectors that have spatial and temporal resolution and approach unit efficiency. We characterize the efficiencies and fidelities of all these steps and evaluate the sensitivity of this approach to measuring $d_e$.

physics.atom-ph↗

arXiv2025

Low-noise environment for probing fundamental symmetries

We present the design and characterization of a low-noise environment for measuring the electron's electric dipole moment (EDM) with a beam of molecules. To minimize magnetic Johnson noise from metals, the design features ceramic electric field plates housed in a glass vacuum chamber. To suppress external magnetic noise the apparatus is enclosed within a cylindrical four-layer mu-metal shield with a shielding factor exceeding $10^6$ in one radial direction and $10^5$ in the other. Finite element modelling shows that the difference between these shielding factors is due to imperfect joints between sections of mu-metal. Using atomic magnetometers to monitor the magnetic field inside the shield, we measure noise below 40 fT/$\sqrt{\rm Hz}$ at 1 Hz and above, rising to 500 fT/$\sqrt{\rm Hz}$ at 0.1 Hz. Analytical and numerical studies show that residual magnetic Johnson noise contributes approximately 13 fT/$\sqrt{\rm Hz}$. The background magnetic field averaged along the beamline is maintained below 3 pT, with typical gradients of a few nT/m. An electric field of 20 kV/cm is applied without discharges and with leakage currents below 1 nA. Each magnetometer measures the magnetic field correlated with the direction of the applied electric field with a precision of 0.11 fT in 104 hours of data. These results demonstrate that the apparatus is suitable for measuring the electron EDM with precision at the $10^{-31}$ e cm level. The design principles and characterization techniques presented here are broadly applicable to precision measurements probing fundamental symmetries in molecules, atoms, and neutrons.

physics.atom-ph↗

arXiv2025

Removal of high-voltage-induced surface charges by ultraviolet light

A plethora of studies ranging from precision physics to quantum information employ ions, highly excited neutral atoms or polar molecules as tools. Motivated by the need for miniaturization, scalability and controllability, the particles are often trapped close to electrodes imprinted on dielectric surfaces. However, such geometry makes the particles susceptible to undesired surface charges. To understand how high voltage applied to the electrodes mediates the buildup of charges, we use a scanning Kelvin probe in an ultrahigh vacuum to investigate the electric potential landscape of an electrostatic molecule trap with a microstructured electrode array. We find that the surface becomes positively charged after applying voltages to the electrodes, leading to offset and patch electric potentials across the surface. Removal of these charges is demonstrated using ultraviolet light. The dynamics of this process, including the dependence on light intensity, wavelength and sample type, are investigated in detail. We find the charge removal to be faster for shorter ultraviolet wavelengths, with an additional polymer coating providing further enhancement. Our findings may be useful in a wide spectrum of experiments with electric-field-sensitive particles.

physics.ins-det↗