Interesting experimental seminar at the Atomic Physics department. --------------------------------------------------------------------------------- Daniel Manzano Quantum Thermodynamics and Quantum Computation Group University of Granada Facultad de Ciencias, Av. Fuentenueva s/n Granada 18071, Spain Phone: +34 958241000 Ext: 20569 https://ic1.ugr.es/members/dmanzano/

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From: María Gómez Rocha <mgomezrocha@ugr.es> Subject: [noticias] Seminario FAMN - viernes 22 nov - 10:00 h - Francisco Domíngez González Date: 20. November 2024 at 09:14:38 CET To: noticias@listas.ugr.es

Estimados compañeros,

El próximo 22 de noviembre a las 10:00h se impartirá el siguiente seminaro en el Departamento de Física Atómica, Molecular y Nuclear.

Un saludo,

María Gómez Rocha

Title: Identifying ions in a linear Paul trap using laser-cooled Coulomb crystals

Abstract: Recently, a new method for the determination of the eigenfrequencies of laser-cooled ions in a Penning trap has been demonstrated in the Ion Traps and Lasers Laboratory at the UGR [1]. The frequencies are determined from the fluorescence photons scattered by the sensor ion when its internal transition is excited by lasers [2]. The technique is universal, non-destructive and allows the measurement of motional frequencies in the quantum regime [3], which will significantly reduce the associated systematic uncertainties.

The realization of such a technique requires the development of novel methods for non-destructive identification measurements with two-ion Coulomb crystals. To this end, a linear Paul trap setup has been commissioned to implement and evaluate a novel optical identification method. In these experiments, two-ion crystals are laser-cooled to temperatures in the millikelvin range and their axial common-mode frequency is probed by a time-oscillating electric field consisting of five radio-frequencies. The resonant excitation of the crystal is read by a photomultiplier tube and the motional frequency is determined by means of the Fast Fourier Transform (FFT) of the detected signal.

In this seminar, I will present the experimental setup and the measurements of the common-axial frequencies of unbalanced (ACa+ - 40Ca+) crystals containing several calcium isotopes (A = 40, 42, 44, 48) using the FFT-based identification method [4]. In addition, the first common-axial frequency measurements of a balanced (40Ca+ - 40Ca+) crystal in the quantum regime will be presented.

[1] J. Berrocal et al, Phys. Rev. Research 6, L012001 (2024)

[2] D. Rodríguez, Appl. Phys. B 107, 1031–1042 (2012)

[3] J. Cerrillo and D. Rodríguez, EPL- Perspective 134, 38001 (2021)

[4] F. Domínguez et al., accepted in Phys. Rev. Research