arXiv subjects

Bassam Nima

Publications and source records attributed to Bassam Nima.

5 recordsLinked to original sources

arXiv2026

Enhanced coherence of rare-earth nuclear spins in a crystal

Rare-earth ions in crystals are useful in precision measurements and quantum information science because of their exceptional optical and spin coherence properties. We show that the nuclear spin coherence time of $^{153}\mathrm{Eu}^{3+}$ ions doped into yttrium orthosilicate can be significantly enhanced by driving the $^{89}\mathrm{Y}$ nuclear spins in the host crystal. This improvement in spin coherence time opens up ways to improve the precision of measurements using rare-earth-doped crystals.

physics.atom-ph↗

arXiv2026

Limit on the nuclear Schiff moment of europium-153

The Schiff moment of a nucleus is a symmetry-violating nuclear moment that indicates new physics beyond the Standard Model. We place the limit, $|\mathscr{S}({}^{153}$Eu)$| < 1.7 \times 10^{-8}$ $e\,$fm$^3$ (95\% confidence), on the Schiff moment of the $^{153}$Eu nucleus, using nuclear spin resonances in two ensembles of oppositely-polarized $^{153}$Eu$^{3+}$ ions in a Y${}_2$SiO${}_5$ crystal. This measurement using octupolar nuclei in a mm-scale crystal constrains new physics at the TeV energy-scale.

physics.atom-ph↗

arXiv2026

Sensing T-violating nuclear moments of paramagnetic ions in crystals

Precision measurements of time-reversal (T) symmetry violating moments probe physics beyond the Standard Model. We show that precision spectroscopy of paramagnetic lanthanide and actinide ions doped into noncentrosymmetric crystals offers a promising platform for extending the sensitivity of searches for T-violation in nuclear physics. The unpaired valence electron in these ions allows the engineering of highly-coherent hyperfine transitions that are insensitive to magnetic fields, yet highly sensitive to new physics. These systems also provide other advantages for new physics searches, including large numbers of ions that can be measured in doped crystals, strong electric polarization of the ions by the crystal fields, enhancement of T-violating nuclear moments in nonspherical nuclei, and accurate comagnetometers generated by crystal symmetry. We estimate the new physics sensitivity of these proposed systems to be two orders of magnitude better than existing constraints.

physics.atom-ph↗

arXiv2024

Comagnetometry using mirror-symmetric ions in a crystal

Searches for physics beyond the Standard Model using spin sensors are susceptible to spurious frequency shifts and noise due to magnetic fields. Therefore a comagnetometer -- an auxiliary sensor that allows mundane magnetic field effects to be differentiated from new physics -- is an essential feature of many precision searches. Here we demonstrate the operation of a novel type of comagnetometer using nuclear spins of dopant ions in a crystal, comparing four different sub-ensembles of ions. We demonstrate rejection of magnetic-field-induced shifts to better than 1 part in 10$^5$ using this system, laying the groundwork for improved searches of time-reversal symmetry violation using solid-state systems.

physics.atom-ph↗

arXiv2024

Wideband Search for Axionlike Dark Matter Using Octupolar Nuclei in a Crystal

Most of the matter in the Universe is in the form of dark matter, which has evaded detection so far. Ultralight axionlike particles (ALPs) are a class of dark matter candidates that produce measurable signatures in the form of oscillating violations of discrete symmetries in nuclei. We report results from a search for an oscillating parity-odd time-reversal-odd nuclear Schiff moment of $^{153}$Eu ions in a crystal, which leads to constraints on ALP-gluon coupling strength across a wide band spanning eight decades in ALP mass.

physics.atom-ph↗