arXiv subjects

Tahiyat Rahman

Publications and source records attributed to Tahiyat Rahman.

4 recordsLinked to original sources

arXiv2026

Lattice-Trapped Atom Interferometry with a Bose-Einstein condensate: Observation and Control of Interactions

Precision interferometry with atomic wavepackets confined in a one-dimensional optical lattice is an emergent paradigm in quantum sensing of forces and fields, with applications in gravimetry, accelerometry, geophysics, and fundamental physics tests. We report on the realization of a lattice-trapped interferometer where the two arms are sourced from a weakly-interacting ytterbium Bose-Einstein condensate, coherently split and trapped by pulsed optical standing waves before recombination. We directly observe atomic interactions through contrast changes and phase shifts of the interferometer. By changing either the atom number or the sample volume to vary the density, we demonstrate control over interactions and optimize interferometer performance. Our observations are effectively captured by a mean-field theoretical model of the system. This work experimentally probes the boundary where improved performance from source brightening through higher phase space density transitions into a regime beyond single-atom physics in lattice-trapped atom interferometry, and opens a door to incorporating many-body effects for metrological advances in such platforms.

cond-mat.quant-gas↗

arXiv2023

Bloch Oscillation Phases investigated by Multi-path Stuckelberg Atom Interferometry

Atoms undergoing Bloch oscillations (BOs) in an accelerating optical lattice acquire momentum of two photon recoils per BO. This technique provides a large momentum transfer tool for atom optics, but its full exploitation for atom interferometric sensors requires experimental characterization of associated phases. Each BO involves a Landau-Zener crossing with multiple crossings inducing interference known as Stuckelberg interference. We develop a multi-path Stuckelberg interferometer and investigate atomic phase evolution during BOs, up to 100 photon recoil momentum transfer. We compare to numerically calculated single-particle Schrodinger evolution, demonstrate highly coherent BO sequences, and assess phase stability requirements for BO-enhanced precision interferometry in fundamental physics and sensing applications.

physics.atom-ph↗

arXiv2021

Interferometry in an Atomic Fountain with Ytterbium Bose-Einstein Condensates

We present enabling experimental tools and atom interferometer implementations in a vertical "fountain" geometry with ytterbium Bose-Einstein condensates. To meet the unique challenge of the heavy, non-magnetic atom, we apply a shaped optical potential to balance against gravity following evaporative cooling and demonstrate a double Mach-Zehnder interferometer suitable for applications such as gravity gradient measurements. Furthermore, we also investigate the use of a pulsed optical potential to act as a matter wave lens in the vertical direction during expansion of the Bose-Einstein condensate. This method is shown to be even more effective and results in a reduction of velocity spread (or equivalently an increase in source brightness) of more than a factor of five, which we demonstrate using a two-pulse momentum-space Ramsey interferometer. The vertical geometry implementation of our diffraction beams ensures that the atomic center of mass maintains overlap with the pulsed atom optical elements, thus allowing extension of atom interferometer times beyond what is possible in a horizontal geometry. Our results thus provide useful tools for enhancing the precision of atom interferometry with ultracold ytterbium atoms.

physics.atom-ph↗

arXiv2020

Crossed-Beam slowing to enhance narrow-line Ytterbium Magneto-Optic Traps

We demonstrate a method to enhance the atom loading rate of a ytterbium (Yb) magneto-optic trap (MOT) operating on the 556 nm ${^1S}_0 \rightarrow {^3P}_1$ intercombination transition (narrow linewidth $Γ_g = 2π\times 182$ kHz). Following traditional Zeeman slowing of an atomic beam near the 399 nm ${^1S}_0 \rightarrow {^1P}_1$ transition (broad linewidth $Γ_p = 2π\times 29 $ MHz), two laser beams in a crossed-beam geometry, frequency tuned near the same transition, provide additional slowing immediately prior to the MOT. Using this technique, we observe an improvement by a factor of 6 in the atom loading rate of a narrow-line Yb MOT. The relative simplicity and generality of this approach make it readily adoptable to other experiments involving narrow-line MOTs. We also present a numerical simulation of this two-stage slowing process which shows good agreement with the observed dependence on experimental parameters, and use it to assess potential improvements to the method.

physics.atom-ph↗