Atomic Physics

Precision measurement of atomic isotope shifts using a two-isotope entangled state (1906.05770v1)

Tom Manovitz, Ravid Shaniv, Yotam Shapira, Roee Ozeri, Nitzan Akerman

2019-06-13

Atomic isotope shifts (ISs) are the isotope-dependent energy differences in the atomic electron energy levels. These shifts serve an important role in atomic and nuclear physics, and particularly in the latter as signatures of nuclear structure. Recently ISs have been suggested as unique probes of beyond Standard Model (SM) physics, under the condition that they be determined significantly more precisely than current state of the art. In this work we present a simple and robust method for measuring ISs with ions in a Paul trap, by taking advantage of Hilbert subspaces that are insensitive to common-mode noise yet sensitive to the IS. Using this method we evaluate the IS of the transition in and with a relative uncertainty to be 570,264,063.435(9) Hz. Furthermore, we detect a relative difference of between the orbital g-factors of the electrons in the level of the two isotopes. Our method is relatively easy to implement and is indifferent to element or isotope, paving the way for future tabletop searches for new physics and posing interesting prospects for testing quantum many-body calculations and for the study of nuclear structure.

In-situ Raman gain between hyperfine ground states in a potassium magneto-optical trap (1906.05756v1)

Graeme Harvie, Adam Butcher, Jon Goldwin

2019-06-13

We study optical gain in a gas of cold 39K atoms. The gain is observed during operation of a conventional magneto-optical trap without the need for additional fields. Measurements of transmission spectra from a weak probe show that the gain is due to stimulated Raman scattering between hyperfine ground states. The experimental results are reproduced by a simplified six-level model, which also helps explain why such gain is not observed in similar experiments with rubidium or cesium.

Cooperative spontaneous emission via renormalization approach: Classical versus semi-classical effects (1906.05719v1)

Carlos Eduardo Máximo, Romain Bachelard, Francisco Ednilson Alves dos Santos, Celso Jorge Villas-Boas

2019-06-13

We address the many-atom emission of a dilute cloud of two-level atoms through a renormalized perturbation theory. An analytical solution for the truncated coupled-dipole equations is derived, which contains an effective spectrum associated to the initial conditions. Our solution is able to distinguish precisely classical from semi-classical predictions for large atomic ensembles. This manifests as a reduction of the cooperativity in the radiated power for higher atomic excitation, in disagreement with the fully classical prediction from linear optics. Moreover, the second-order cooperative emission appears accurate over several single atom lifetimes and for interacting regimes stronger than those permitted in conventional perturbation theory. We can compute the semiclassical dynamics of hundred thousand of interacting atoms with ordinary computational resources, which makes our formalism particularly promising to probe the nonlinear dynamics of quantum many-body systems that emerge from cumulant expansions.

Effect of laser frequency fluctuation on the decay rate of Rydberg coherence (1902.09845v4)

Bongjune Kim, Ko-Tang Chen, Chia-Yu Hsu, Shih-Si Hsiao, Yu-Chih Tseng, Chin-Yuan Lee, Shih-Lun Liang, Yi-Hua Lai, Julius Ruseckas, Gediminas Juzeliunas, Ite A. Yu

2019-02-26

The effect of electromagnetically induced transparency (EIT) combined with Rydberg-state atoms provides high optical nonlinearity to efficiently mediate the photon-photon interaction. However, the decay rate of Rydberg coherence, i.e., the decoherence rate, plays an important role in optical nonlinear efficiency, and can be largely influenced by laser frequency fluctuation. In this work, we carried out a systematic study of the effect of laser frequency fluctuation on the decoherence rate. We derived an analytical formula that quantitatively describes the relationship between the decoherence rate and laser frequency fluctuation. The formula was experimentally verified by using the -type EIT system of laser-cooled Rb atoms, in which one can either completely eliminate or controllably introduce the effect of laser frequency fluctuation. We also included the effect of Doppler shift caused by the atomic thermal motion in the formula, which can be negligible in the -type EIT experiment but significant in the Rydberg-EIT experiment. Utilizing the atoms of 350 K, we studied the decoherence rate in the Rydberg-EIT system involving with the state of . The experimental data are consistent with the predictions from the formula. We were able to achieve a rather low decoherence rate of 48 kHz at a moderate coupling Rabi frequency of 4.3 MHz.

Microwave trap for atoms and molecules (1906.05380v1)

S. C. Wright, T. E. Wall, M. R. Tarbutt

2019-06-12

We demonstrate a trap that confines polarizable particles around the antinode of a standing-wave microwave field. The trap relies only on the polarizability of the particles far from any resonances, so can trap a wide variety of atoms and molecules in a wide range of internal states, including the ground state. The trap has a volume of about 10 cm, and a depth approaching 1 K for many polar molecules. We measure the trap properties using Li atoms, showing that when the input microwave power is 610 W, the atoms remain trapped with a lifetime of 1.76(12) s, oscillating with an axial frequency of 28.55(5) Hz and a radial frequency of 8.81(8) Hz. The trap is particularly well suited to sympathetic cooling and evaporative cooling of molecules.

Revisiting the Fe XVII line emission problem: laboratory measurements of the 3s-2p and 3d-2p line-formation channels (1903.04506v2)

Chintan Shah, José R. Crespo López-Urrutia, Ming Feng Gu, Thomas Pfeifer, José Marques, Filipe Grilo, José Paulo Santos, Pedro Amaro

2019-03-11

We determined relative X-ray photon emission cross sections in Fe XVII ions that were mono-energetically excited in an electron beam ion trap. Line formation for the 3s (3s-2p) and 3d (3d-2p) transitions of interest proceeds through dielectronic recombination (DR), direct electron-impact excitation (DE), resonant excitation (RE), and radiative cascades. By reducing the electron-energy spread to a sixth of that of previous works and increasing counting statistics by three orders of magnitude, we account for hitherto unresolved contributions from DR and the little-studied RE process to the 3d transitions, and also for cascade population of the 3s line manifold through forbidden states. We found good agreement with state-of-the-art many-body perturbation theory (MBPT) and distorted-wave (DW) method for the 3s transition, while in the 3d transitions known discrepancies were confirmed. Our results show that DW calculations overestimate the 3d line emission due to DE by ~20%. Inclusion of electron-electron correlation effects through the MBPT method in the DE cross section calculations reduces this disagreement by ~11%. The remaining ~9% in 3d and ~11% in 3s/3d discrepancies are consistent with those found in previous laboratory measurements, solar, and astrophysical observations. Meanwhile, spectral models of opacity, temperature, and turbulence velocity should be adjusted to these experimental cross sections to optimize the accuracy of plasma diagnostics based on these bright soft X-ray lines of Fe XVII.

Perfect control of photoelectron anisotropy for randomly oriented ensembles of molecules by XUV REMPI and polarization shaping (1906.05207v1)

R. Esteban Goetz, Christiane P. Koch, Loren Greenman

2019-06-12

We report two schemes to generate perfect anisotropy in the photoelectron angular distribution of a randomly oriented ensemble of polyatomic molecules. In order to exert full control over the anisotropy of photoelectron emission, we exploit interferences between single-photon pathways and a manifold of resonantly-enhanced two-photon pathways. These are shown to outperform non-sequential bichromatic phase control for the example of CHFClBr molecules. We are able to optimize pulses that yield anisotropic photoelectron emission thanks to a very efficient calculation of photoelectron momentum distributions. This is accomplished by combining elements of quantum chemistry, variational scattering theory, and time-dependent perturbation theory.

Observation of a large, resonant, cross-Kerr nonlinearity in a free-space Rydberg medium (1906.05151v1)

Josiah Sinclair, Daniela Angulo, Noah Lupu-Gladstein, Kent Bonsma-Fisher, Aephraim M. Steinberg

2019-06-12

We report the experimental observation of a cross-Kerr nonlinearity in a free-space medium based on resonantly-excited, interacting Rydberg atoms and electromagnetically induced transparency. The nonlinearity is used to implement cross-phase modulation between two optical pulses. The nonlinear phase written onto the probe pulse is measured to be as large as mrad per nW of signal power, corresponding to a of . Potential applications range from optical quantum information processing to quantum non-demolition measurement of photon number.

Final result of CUPID-0 phase-I in the search for the Se Neutrinoless Double Beta Decay (1906.05001v1)

O. Azzolini, J. W. Beeman, F. Bellini, M. Beretta, M. Biassoni, C. Brofferio, C. Bucci, S. Capelli, L. Cardani, P. Carniti, N. Casali, D. Chiesa, M. Clemenza, O. Cremonesi, A. Cruciani, I. Dafinei, S. Di Domizio, F. Ferroni, L. Gironi, A. Giuliani, P. Gorla, C. Gotti, G. Keppel, M. Martinez, S. Nagorny, M. Nastasi, S. Nisi, C. Nones, D. Orlandi, L. Pagnanini, M. Pallavicini, L. Pattavina, M. Pavan, G. Pessina, V. Pettinacci, S. Pirro, S. Pozzi, E. Previtali, A. Puiu, C. Rusconi, K. Schäffner, C. Tomei, M. Vignati, A. S. Zolotarova

2019-06-12

CUPID-0 is the first pilot experiment of CUPID, a next-generation project for the measurement of neutrinoless double beta decay (0DBD) with scintillating bolometers. The detector, consisting of 24 enriched and 2 natural ZnSe crystals, has been taking data at Laboratori Nazionali del Gran Sasso from June 2017 to December 2018, collecting a Se exposure of 5.29 kgyr. In this paper we present the phase-I results in the search for 0DBD. We demonstrate that the technology implemented by CUPID-0 allows us to reach the lowest background for calorimetric experiments: counts/(keV kg yr). Monitoring 3.8810 Se nucleiyr we reach a 90% credible interval median sensitivity of and set the most stringent limit on the half-life of Se 0DBD : (90% credible interval), corresponding to m (311-638) meV depending on the nuclear matrix element calculations.

Phase-Noise and Amplitude-Noise Measurement of DACs and DDSs (1906.04954v1)

Claudio E. Calosso, A. Carolina Cárdenas Olaya, Enrico Rubiola

2019-06-12

This article proposes a method for the measurement of Phase Noise (PN, or PM noise) and Amplitude Noise (AN, or AM noise) of Digital-to-Analog Converters (DAC) and Direct Digital Synthesizers (DDS) based on modulation-index amplification. The carrier is first reduced by a controlled amount (30-40 dB) by adding a reference signal of nearly equal amplitude and opposite in phase. Then, residual carrier and noise sidebands are amplified and sent to a conventional PN analyzer. The main virtues of our method are: (i) the noise specs of the PN analyzer are relaxed by a factor equal to the carrier suppression ratio; and, (ii) the capability to measure the AN using a PN analyzer, with no need for the analyzer to feature AN measurement. An obvious variant enables AN and PN measurements using an AN analyzer with no PN measurement capability. Such instrument is extremely simple and easy to implement with a power-detector diode followed by a FFT analyzer. Unlike the classical bridge (interferometric) method, there is no need for external line stretcher and variable attenuators because phase and amplitude control is implemented in the device under test. In one case (AD9144), we could measure the noise over 10 decades of frequency. The flicker noise matches the exact law with a maximum discrepancy of dB over 7.5 decades. Thanks to simplicity, reliability, and low background noise, this method has the potential to become the standard method for the AN and PN measurement of DACs and DDSs.

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Atomic Physics Latest Preprints | 2019-06-15

Atomic Physics

Precision measurement of atomic isotope shifts using a two-isotope entangled state (1906.05770v1)

In-situ Raman gain between hyperfine ground states in a potassium magneto-optical trap (1906.05756v1)

Cooperative spontaneous emission via renormalization approach: Classical versus semi-classical effects (1906.05719v1)

Effect of laser frequency fluctuation on the decay rate of Rydberg coherence (1902.09845v4)

Microwave trap for atoms and molecules (1906.05380v1)

Revisiting the Fe XVII line emission problem: laboratory measurements of the 3s-2p and 3d-2p line-formation channels (1903.04506v2)

Perfect control of photoelectron anisotropy for randomly oriented ensembles of molecules by XUV REMPI and polarization shaping (1906.05207v1)

Observation of a large, resonant, cross-Kerr nonlinearity in a free-space Rydberg medium (1906.05151v1)

Final result of CUPID-0 phase-I in the search for the Se Neutrinoless Double Beta Decay (1906.05001v1)

Phase-Noise and Amplitude-Noise Measurement of DACs and DDSs (1906.04954v1)