A remote sensor for electromagnetic personal safety monitoring

Abstract: Citizens are often afraid of electromagnetic fields. This creates a need for logging and quantifying the exposure to fields in the civil environment. An electromagnetic field strength sensor (from 1MHz to 1GHz) has been developed which is connected to a logging system and a modem. The systems output level is independent of frequencies i.e. follows the standards limit curve. It can be powered by solar cells. So it can operate without human interaction anywhere. The system can emit a warning when the exposure level is exceeded. In normal mode, it transmits the logged levels once per week to a central data collection system. This paper describes the design and operation of the system

A compact design for the Josephson mixer: the lumped element circuit

We present a compact and efficient design in terms of gain, bandwidth and dynamical range for the Josephson mixer, the superconducting circuit performing three-wave mixing at microwave frequencies. In an all lumped-element based circuit with galvanically coupled ports, we demonstrate non degenerate amplification for microwave signals over a bandwidth up to 50 MHz for a power gain of 20 dB. The quantum efficiency of the mixer is shown to be about 70$\%$ and its saturation power reaches $-112$ dBm.Comment: 5 pages, 4 figure

Two-particle spatial correlations in superfluid nuclei

We discuss the effect of pairing on two-neutron space correlations in deformed nuclei. The spatial correlations are described by the pairing tensor in coordinate space calculated in the HFB approach. The calculations are done using the D1S Gogny force. We show that the pairing tensor has a rather small extension in the relative coordinate, a feature observed earlier in spherical nuclei. It is pointed out that in deformed nuclei the coherence length corresponding to the pairing tensor has a pattern similar to what we have found previously in spherical nuclei, i.e., it is maximal in the interior of the nucleus and then it is decreasing rather fast in the surface region where it reaches a minimal value of about 2 fm. This minimal value of the coherence length in the surface is essentially determined by the finite size properties of single-particle states in the vicinity of the chemical potential and has little to do with enhanced pairing correlations in the nuclear surface. It is shown that in nuclei the coherence length is not a good indicator of the intensity of pairing correlations. This feature is contrasted with the situation in infinite matter.Comment: 14 pages, 17 figures, submitted to PR

Convergence of Particle-Hole Expansions for the Description of Nuclear Correlations

The convergence properties of a multiparticle-multihole (mp-mh) configuration mixing approach whose purpose is to describe ground state correlations in nuclei without particle number and Pauli violations is investigated in the case of an exactly solvable pairing hamiltonian. Two different truncation schemes are tested by looking at quantities as correlation energies and single-particle occupation probabilities. Results show that pairing correlations present in usual superfluid nuclei can be accurately described using up to 6 particle-6 hole excitations, a convergence fast enought for envisaging extensions to fully microscopic calculations.Comment: 8 pages, 4 figure

Description of nuclear systems with a self-consistent configuration-mixing approach. I: Theory, algorithm, and application to the 12^{12}C test nucleus

Although self-consistent multi-configuration methods have been used for decades to address the description of atomic and molecular many-body systems, only a few trials have been made in the context of nuclear structure. This work aims at the development of such an approach to describe in a unified way various types of correlations in nuclei, in a self-consistent manner where the mean-field is improved as correlations are introduced. The goal is to reconcile the usually set apart Shell-Model and Self-Consistent Mean-Field methods. This approach is referred as "variational multiparticle-multihole configuration mixing method". It is based on a double variational principle which yields a set of two coupled equations that determine at the same time the expansion coefficients of the many-body wave function and the single particle states. The formalism is derived and discussed in a general context, starting from a three-body Hamiltonian. Links to existing many-body techniques such as the formalism of Green's functions are established. First applications are done using the two-body D1S Gogny effective force. The numerical procedure is tested on the $^{12}$C nucleus in order to study the convergence features of the algorithm in different contexts. Ground state properties as well as single-particle quantities are analyzed, and the description of the first $2^+$ state is examined. This study allows to validate our numerical algorithm and leads to encouraging results. In order to test the method further, we will realize in the second article of this series, a systematic description of more nuclei and observables obtained by applying the newly-developed numerical procedure with the same Gogny force. As raised in the present work, applications of the variational multiparticle-multihole configuration mixing method will however ultimately require the use of an extended and more constrained Gogny force.Comment: 22 pages, 18 figures, accepted for publication in Phys. Rev. C. v2: minor corrections and references adde

Laser and microwave spectroscopy of even-parity Rydberg states of neutral ytterbium and Multichannel Quantum Defect Theory analysis

New measurements of high-lying even parity $6sns\, {}^1 \! S_0$ and $6snd\,{}^{3,1}\!D_2$ levels of neutral $^{174}$Yb are presented in this paper. Spectroscopy is performed by a two-step laser excitation from the ground state $4f^{14}6s^2 \, {}^1 \! S_0$, and the Rydberg levels are detected by using the field ionization method. Additional two-photon microwave spectroscopy is used to improve the relative energy accuracy where possible. The spectroscopic measurements are complemented by a multichannel quantum defect theory (MQDT) analysis for the J=0 and the two-coupled J=2 even parity series. We compare our results with the previous analysis of Aymar {\it{et al}} \cite{Aymar_1980} and analyze the observed differences. From the new MQDT models, a revised value for the first ionization limit $I_{6s}=50443.07041(25)$ cm$^{-1}$ is proposed.Comment: 15 pages, 3 figure

Structure of even-even nuclei using a mapped collective Hamiltonian and the D1S Gogny interaction

A systematic study of low energy nuclear structure at normal deformation is carried out using the Hartree-Fock-Bogoliubov theory extended by the Generator Coordinate Method and mapped onto a 5-dimensional collective quadrupole Hamiltonian. Results obtained with the Gogny D1S interaction are presented from dripline to dripline for even-even nuclei with proton numbers Z=10 to Z=110 and neutron numbers N less than 200. The properties calculated for the ground states are their charge radii, 2-particle separation energies, correlation energies, and the intrinsic quadrupole shape parameters. For the excited spectroscopy, the observables calculated are the excitation energies and quadrupole as well as monopole transition matrix elements. We examine in this work the yrast levels up to J=6, the lowest excited 0^+ states, and the two next yrare 2^+ states. The theory is applicable to more than 90% of the nuclei which have tabulated measurements. The data set of the calculated properties of 1712 even-even nuclei, including spectroscopic properties for 1693 of them, are provided in CEA website and EPAPS repository with this article \cite{epaps}.Comment: 51 pages with 26 Figures and 4 internal tables; this version is accepted by Physical Review

Observation of a resonant four-body interaction in cold cesium Rydberg atoms

Cold Rydberg atoms subject to long-range dipole-dipole interactions represent a particularly interesting system for exploring few-body interactions and probing the transition from 2-body physics to the many-body regime. In this work we report the direct observation of a resonant 4-body Rydberg interaction. We exploit the occurrence of an accidental quasi-coincidence of a 2-body and a 4-body resonant Stark-tuned Forster process in cesium to observe a resonant energy transfer requiring the simultaneous interaction of at least four neighboring atoms. These results are relevant for the implementation of quantum gates with Rydberg atoms and for further studies of many-body physics.Comment: 5 pages, 5 figure

Coherent excitation of a single atom to a Rydberg state

We present the coherent excitation of a single Rubidium atom to the Rydberg state (58d3/2) using a two-photon transition. The experimental setup is described in detail, as well as experimental techniques and procedures. The coherence of the excitation is revealed by observing Rabi oscillations between ground and Rydberg states of the atom. We analyze the observed oscillations in detail and compare them to numerical simulations which include imperfections of our experimental system. Strategies for future improvements on the coherent manipulation of a single atom in our settings are given