Search results for "Physics - Atomic Physic"
showing 10 items of 342 documents
Four-wave mixing in a ring cavity
2014
We investigate a four-wave mixing process in an N interaction scheme in Rb vapor placed inside a low-finesse ring cavity. We observe strong amplification and generation of a probe signal, circulating in the cavity, in the presence of two strong optical pump fields. We study the variations in probe field gain and dispersion as functions of experimental parameters with an eye on potential application of such a system for enhanced rotation measurements. A density-matrix calculation is performed to model the system, and the theoretical results are compared to those of the experiment.
Extending the applicability of an open-ring trap to perform experiments with a single laser-cooled ion.
2015
An open-ring ion trap, also referred to as transparent trap was initially built up to perform $\beta$-$\nu$ correlation experiments with radioactive ions. This trap geometry is also well suited to perform experiments with laser-cooled ions, serving for the development of a new type of Penning trap, in the framework of the project TRAPSENSOR at the University of Granada. The goal of this project is to use a single $^{40}$Ca$^+$ ion as detector for single-ion mass spectrometry. Within this project and without any modification to the initial electrode configuration, it was possible to perform Doppler cooling on $^{40}$Ca$^+$ ions, starting from large clouds and reaching single ion sensitivity.…
Efficient and robust photo-ionization loading of beryllium ions
2017
We demonstrate the efficient generation of Be$^+$ ions with a 60 ns and 150 nJ laser pulse near 235 nm for two-step photo-ionization, proven by subsequent counting the number of ions loaded into a linear Paul trap. The bandwidth and power of the laser pulse are chosen in such a way that a first, resonant step fully saturates the entire velocity distribution of beryllium atoms effusing from a thermal oven. The second excitation step is driven by the same light field causing efficient non-resonant ionization. Our ion-loading scheme is more than 15 times more efficient as compared to former pathways using two-photon continuous wave laser excitation.
High-Spatial-Resolution Monitoring of Strong Magnetic Field using Rb vapor Nanometric-Thin Cell
2011
We have implemented the so-called $\lambda$-Zeeman technique (LZT) to investigate individual hyperfine transitions between Zeeman sublevels of the Rb atoms in a strong external magnetic field $B$ in the range of $2500 - 5000$ G (recently it was established that LZT is very convenient for the range of $10 - 2500$ G). Atoms are confined in a nanometric thin cell (NTC) with the thickness $L = \lambda$, where $\lambda$ is the resonant wavelength 794 nm for Rb $D_1$ line. Narrow velocity selective optical pumping (VSOP) resonances in the transmission spectrum of the NTC are split into several components in a magnetic field with the frequency positions and transition probabilities depending on th…
Testing isotropy of the universe using the Ramsey resonance technique on ultracold neutron spins
2010
Physics at the Planck scale could be revealed by looking for tiny violations of fundamental symmetries in low energy experiments. In 2008, a sensitive test of the isotropy of the Universe using has been performed with stored ultracold neutrons (UCN), this is the first clock-comparison experiment performed with free neutrons. During several days we monitored the Larmor frequency of neutron spins in a weak magnetic field using the Ramsey resonance technique. An non-zero cosmic axial field, violating rotational symmetry, would induce a daily variation of the precession frequency. Our null result constitutes one of the most stringent tests of Lorentz invariance to date.
Searching for Scalar Dark Matter in Atoms and Astrophysical Phenomena: Variation of Fundamental Constants
2015
Stadnik, Yevgeny V. "Searching for Scalar Dark Matter in Atoms and Astrophysical Phenomena: Variation of Fundamental Constants" in Proceedings, 11th Patras Workshop on Axions, WIMPs and WISPs (Axion-WIMP 2015) / Irastorza, Igor G., Redondo, Javier, Carmona, José Manuel, Cebrian, Susana, Dafni, Theopisti, Iguaz, Francisco J., Luzon, Gloria (eds.), Verlag Deutsches Elektronen-Synchrotron : 2015 ; AXION-WIMP 2015 : 11th Patras Workshop on Axions, WIMPs and WISPs, 2015-06-22 - 2015-06-26, Zaragoza 11th Patras Workshop on Axions, WIMPs and WISPs, AXION-WIMP 2015, Zaragoza, Spain, 22 Jun 2015 - 26 Jun 2015 ; DESY-PROC 169-172(2015). doi:10.3204/DESY-PROC-2015-02/roberts_benjamin
Enhanced nuclear Schiff moment and time reversal violation in 229Th-containing molecules
2018
Octupole deformation results in a strongly enhanced collective Schiff moment in 229Th nucleus. An additional enhancement of time reversal (T) and parity (P) violating effects (such as T,P-violating electric dipole moments) appears in the ground 1Sigma state and in the metastable 3Delta_1 state of diatomic molecule 229ThO. Similar enhancements exist in molecular ions 229ThOH+, 229ThF+ and 225,223RaOH+. Corresponding experiments may be used to test CP-violation theories predicting T,P-violating nuclear forces and to search for axions.
Theoretical study of $^{173}$YbOH to search for the nuclear magnetic quadrupole moment
2019
CP-violating interaction of the nuclear magnetic quadrupole moment (MQM) with electrons in the ytterbium mono-hydroxide molecule, $^{173}$YbOH, is considered. Both the magnetic quadrupole moment (MQM) of the $^{173}$Yb nucleus and the molecular interaction constant WM are estimated. Electron correlation effects are taken into account within the relativistic Fock-space coupled cluster method. Results are interpreted in terms of the strength constants of CP-violating nuclear forces, neutron EDM, QCD vacuum angle $\theta$, quark EDM and chromo-EDM.
Searching for Axion Dark Matter in Atoms: ~Oscillating Electric Dipole Moments and Spin-Precession Effects
2015
Roberts, Benjamin M. "Searching for Axion Dark Matter in Atoms: ~Oscillating Electric Dipole Moments and Spin-Precession Effects" in Proceedings, 11th Patras Workshop on Axions, WIMPs and WISPs (Axion-WIMP 2015) / Irastorza, Igor G., Redondo, Javier, Carmona, José Manuel, Cebrian, Susana, Dafni, Theopisti, Iguaz, Francisco J., Luzon, Gloria (eds.), Verlag Deutsches Elektronen-Synchrotron : 2015 ; AXION-WIMP 2015 : 11th Patras Workshop on Axions, WIMPs and WISPs, 2015-06-22 - 2015-06-26, Zaragoza 11th Patras Workshop on Axions, WIMPs and WISPs, AXION-WIMP 2015, Zaragoza, Spain, 22 Jun 2015 - 26 Jun 2015 ; DESY-PROC 120-123(2015). doi:10.3204/DESY-PROC-2015-02/roberts_benjamin_axions
Internal conversion from excited electronic states of $^{229}{\mathrm Th}$ ions
2016
The process of internal conversion from excited electronic states is investigated theoretically for the case of the vacuum-ultraviolet nuclear transition of $^{229}{\mathrm Th}$. Due to the very low transition energy, the $^{229}{\mathrm Th}$ nucleus offers the unique possibility to open the otherwise forbidden internal conversion nuclear decay channel for thorium ions via optical laser excitation of the electronic shell. We show that this feature can be exploited to investigate the isomeric state properties via observation of internal conversion from excited electronic configurations of ${\mathrm Th}^+$ and ${\mathrm Th}^{2+}$ ions. A possible experimental realization of the proposed scena…