arXiv subjects

Guglielmo Panelli

Publications and source records attributed to Guglielmo Panelli.

4 recordsLinked to original sources

arXiv2026

Microsecond-Scale Coherent Control of a Forbidden Clock Transition with Doppler-Free Multiphoton Excitations

We demonstrate two Doppler-free (DF) excitation schemes for coherent manipulation of the ${}^1\!S_0 - {}^3\!P_0$ clock transition in $^{88}$Sr that achieve microsecond-scale excitation times. The first approach uses three-photon excitation with distinct phase-coherent spectral components to couple the ground and clock states while canceling the first-order Doppler shift. The second approach is a sequential protocol that combines a single-photon excitation with a two-photon Raman excitation, reducing coherent clock transition manipulation times to below a microsecond. With both methods, we perform high-contrast Ramsey spectroscopy on thermal ensembles of $3 \times 10^{6}$ atoms in free space. We observe three orders of magnitude suppression of Doppler dephasing compared to single-photon excitation, relaxing the need for tight confinement or ultra-low temperatures. These broadly applicable techniques enable fast, coherent manipulation of narrow-line transitions, with implications for optical atomic clocks, matter-wave interferometers, quantum-enhanced metrology, and quantum information processing.

physics.atom-ph↗

arXiv2024

Doppler-free three-photon spectroscopy on narrow-line optical transitions

We demonstrate coherent Doppler-free three-photon excitation of the $^{1}S_{0}$$\leftrightarrow$$^{3}P_{0}$ optical clock transition and the $^{1}S_{0}$$\leftrightarrow$$^{3}P_{1}$ intercombination transition in free-space thermal clouds of $^{88}$Sr atoms. By appropriate orientation of the wavevectors of three lasers incident on the atoms, the first-order Doppler shift can be eliminated for all velocity classes. Three-photon excitation of the $^{1}S_{0}$$\leftrightarrow$$^{3}P_{1}$ transition enables high-contrast Ramsey spectroscopy with interrogation times comparable to the 21$μ$s natural lifetime using a single near-resonant laser source. Three-photon spectroscopy on the $^{1}S_{0}$$\leftrightarrow$$^{3}P_{0}$ clock transition, using only laser frequencies nearly resonant with the $^{1}S_{0}$$\leftrightarrow$$^{3}P_{0}$ and $^{1}S_{0}$$\leftrightarrow$$^{3}P_{1}$ transitions, enables a reduction in Doppler broadening by two orders of magnitude and a corresponding $\sim470$Hz linewidth without a confining potential.

physics.atom-ph↗

arXiv2020

Investigating resonant low-energy electron attachment to formamide: dynamics of model peptide bond dissociation and other fragmentation channels

We report experimental results on three-dimensional momentum imaging measurements of anions generated via dissociative electron attachment to gaseous formamide. From the momentum images, we analyze the angular and kinetic energy distributions for NH$_2^{-}$, O$^{-}$, and H$^{-}$ fragments and discuss the possible electron attachment and dissociation mechanisms for multiple resonances for two ranges of incident electron energies, from 5.3~eV to 6.8~eV, and from 10.0~eV to 11.5~eV. {\it Ab initio} theoretical results for the angular distributions of the NH$_2^{-}$ anion for $\sim$6~eV incident electrons, when compared with the experimental results, strongly suggest that one of the two resonances producing this fragment is a $^2$A$''$ Feshbach resonance.

physics.chem-ph↗

arXiv2019

Applying the matched-filter technique to the search for dark matter transients with networks of quantum sensors

There are several networks of precision quantum sensors in existence, including networks of atomic clocks, magnetometers, and gravitational wave detectors. These networks can be re-purposed for searches of exotic physics, such as direct dark matter searches. Here we explore a detection strategy for macroscopic dark matter objects with such networks using the matched-filter technique. Such "clumpy" dark matter objects would register as transients sweeping through the network at galactic velocities. As a specific example, we consider a network of atomic clocks aboard the Global Positioning System (GPS) satellites. We apply the matched-filter technique to simulated GPS atomic clock data and study its utility and performance. The analysis and the developed methodology have a wide applicability to other networks of quantum sensors.

astro-ph.IM↗