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8,800 | Retarded long-range potentials for the alkali-metal atoms and a perfectly conducting wall | physics.atom-ph | The retarded long-range potentials for hydrogen and alkali-metal atoms in
their ground states and a perfectly conducting wall are calculated. The
potentials are given over a wide range of atom-wall distances and the validity
of the approximations used is established. | physics |
8,801 | Eight-component differential equation for leptonium | physics.atom-ph | It is shown that the potential for lepton-antilepton bound states (leptonium)
is the Fourier transform of the first Born approximation to the QED scattering
amplitude in an 8-component equation, while 16-component equations are
excluded. The Fourier transform is exact at all cms energies $-\infty < E <
\infty$; the res... | physics |
8,802 | Formation of antihydrogen atoms in an ultra-cold positron-antiproton plasma | physics.atom-ph | We discuss the formation of antihydrogen atoms ($\bar{\rm H}$) in an
ultra-cold positron-antiproton plasma. For positron densities $n_p\agt 10^8$
cm$^{-3}$ the characteristic formation time of stable $\bar{H}$ is determined
by collisional relaxation of highly excited atoms produced in the process of
3-body Thompson rec... | physics |
8,803 | Coherent Population Trapping with Losses on the Sodium D1 Line Hanle Effect | physics.atom-ph | We consider the coherent population trapping phenomenon in a thermal sodium
atomic beam. We compare the different coherent population trapping schemes that
can be established on the D1 line using the Zeeman sublevels of a given ground
hyperfine state. The coherent population trapping preparation is examined by
means of... | physics |
8,804 | Ramsey type Sub-Recoil Cooling | physics.atom-ph | We experimentally study the motion of atoms interacting with a periodically
pulsed near resonant standing wave. For discrete pulse frequencies we observe a
comb-like momentum distribution. The peaks have widths of 0.3 recoil momenta
and a spacing which is an integer multiple of the recoil momentum. The atomic
populatio... | physics |
8,805 | Band Population Measurements in a Purely Optical Dark Lattice | physics.atom-ph | We create a dark optical lattice structure using a blue detuned laser field
coupling an atomic ground state of total angular momentum F simultaneously to
two excited states with angular momenta F and F-1, or F and F+1. The atoms are
trapped at locations of purely circular polarization. The cooling process
efficiently a... | physics |
8,806 | An all-optical gray lattice for atoms | physics.atom-ph | We create a gray optical lattice structure using a blue detuned laser field
coupling an atomic ground state of angular momentum J simultaneously to two
excited states with angular momenta J and J-1. The atoms are cooled and trapped
at locations of purely circular polarization. The cooling process efficiently
accumulate... | physics |
8,807 | On the squared spin-orbit correction to the positronium fine-structure splitting | physics.atom-ph | In the recent paper by Zhang the order $\alpha^4 R_{\infty}$ corrections to
the positronium P levels were reconsidered. Those calculations confirm our
corresponding results, except for the contribution due to the squared
spin-orbit interaction. We present here a new derivation of our previous result
for this last corre... | physics |
8,808 | Ejection Energy of Photoelectrons in Strong Field Ionization | physics.atom-ph | We show that zero ejection energy of the photoelectrons is classically
impossible for hydrogen-like ions, even when field ionization occurs
adiabatically. To prove this we transform the basic equations to those
describing two 2D anharmonic oscillators. The same method yields an alternative
way to derive the anomalous c... | physics |
8,809 | Adiabatically changing the phase-space density of a trapped Bose gas | physics.atom-ph | We show that the degeneracy parameter of a trapped Bose gas can be changed
adiabatically in a reversible way, both in the Boltzmann regime and in the
degenerate Bose regime. We have performed measurements on spin-polarized atomic
hydrogen in the Boltzmann regime demonstrating reversible changes of the
degeneracy parame... | physics |
8,810 | Interference of Resonance Fluorescence from two four-level atoms | physics.atom-ph | In a recent experiment by Eichmann et al., polarization-sensitive
measurements of the fluorescence from two four-level ions driven by a linearly
polarized laser were made. Depending on the polarization chosen, different
degrees of interference were observed. We carry out a theoretical and numerical
study of this system... | physics |
8,811 | Long-range interactions of lithium atoms | physics.atom-ph | The long-range interactions of two atoms, of an atom and a dielectric wall,
of an atom and a perfectly conducting wall, and of an atom between two
perfectly conducting walls are calculated, including the effects of
retardation, for Li using dynamic polarizabilities determined from highly
correlated, variationally deter... | physics |
8,812 | Steady state behaviour in atomic three-level lambda and ladder systems with incoherent population pumping | physics.atom-ph | The steady state in three-level lambda and ladder systems is studied. It is
well-known that in a lambda system this steady state is the coherent population
trapping state, independent of the presence of spontaneous emission. In
contrast, the steady state in a ladder system is in general not stable against
radiative dec... | physics |
8,813 | The hyperfine structure of the hydrogen molecular ion | physics.atom-ph | Theoretical investigations of the hyperfine structure of the hydrogen
molecular ion (one electron and two protons) are discussed. The nuclear
spin-rotation interaction has been found to be of the same sign as in the
hydrogen molecule and the hyperfine transition frequencies can be accurately
predicted. With measurement... | physics |
8,814 | Three-potential formalism for the atomic three-body problem | physics.atom-ph | Based on a three-potential formalism we propose mathematically well-behaved
Faddeev-type integral equations for the atomic three-body problem and descibe
their solutions in Coulomb-Sturmian space representation. Although the system
contains only long-range Coulomb interactions these equations allow us to reach
solution... | physics |
8,815 | Multiphoton detachment of electrons from negative ions | physics.atom-ph | A simple analytical solution for the problem of multiphoton detachment from
negative ions by a linearly polarized laser field is found. It is valid in the
wide range of intensities and frequencies of the field, from the perturbation
theory to the tunneling regime, and is applicable to the excess-photon as well
as near-... | physics |
8,816 | Multiphoton detachment from negative ions: new theory vs experiment | physics.atom-ph | In this paper we compare the results of our adiabatic theory (Gribakin and
Kuchiev, Phys. Rev. A, accepted for publication) with other theoretical and
experimental results, mostly for halogen negative ions. The theory is based on
the Keldysh approach. It shows that the multiphoton detachment rates and the
corresponding... | physics |
8,817 | Collisional Semiclassical Aproximations in Phase-Space Representation | physics.atom-ph | The Gaussian Wave-Packet phase-space representation is used to show that the
expansion in powers of $\hbar$ of the quantum Liouville propagator leads, in
the zeroth order term, to results close to those obtained in the statistical
quasiclassical method of Lee and Scully in the Weyl-Wigner picture. It is also
verified t... | physics |
8,818 | Radiative Corrections to the 2E1 Decay Rate of the 2s-State in Hydrogen-Like Atoms | physics.atom-ph | Radiative corrections to the 2E1 decay width of the 2s-state in the low-Z
hydrogen-like system are examined within logarithmic approximation. The
correction is found to be 2.025(1) alpha (Z alpha)^2 / pi log(Z alpha)^2 in
units of the non-relativistic rate. | physics |
8,819 | Radiative Corrections to the Light Muonic Atoms Decay Rate | physics.atom-ph | Radiative corrections to the decay rate in the low-Z hydrogen-like muonic
atoms are considered. The correction arises from the Uehling potential and it
has the relative order of alpha. The numerical results are reported for the
2p-1s transition for the atom with the nuclear charge value up to Z=10. | physics |
8,820 | Photodetachment study of the 1s3s4s ^4S resonance in He^- | physics.atom-ph | A Feshbach resonance associated with the 1s3s4s ^{4}S state of He^{-} has
been observed in the He(1s2s ^{3}S) + e^- (\epsilon s) partial photodetachment
cross section. The residual He(1s2s ^{3}S) atoms were resonantly ionized and
the resulting He^+ ions were detected in the presence of a small background. A
collinear l... | physics |
8,821 | The electron affinity of tellurium | physics.atom-ph | The electron affinity of tellurium has been determined to 1.970 876(7) eV.
The threshold for photodetachment of Te^-(^{2} P_{3/2}) forming neutral Te in
the ground state was investigated by measuring the total photodetachment cross
section using a collinear laser-ion beam geometry. The electron affinity was
obtained fr... | physics |
8,822 | Electron affinity of Li: A state-selective measurement | physics.atom-ph | We have investigated the threshold of photodetachment of Li^- leading to the
formation of the residual Li atom in the $2p ^2P$ state. The excited residual
atom was selectively photoionized via an intermediate Rydberg state and the
resulting Li^+ ion was detected. A collinear laser-ion beam geometry enabled
both high re... | physics |
8,823 | Resonance structure in the Li^- photodetachment cross section | physics.atom-ph | We report on the first observation of resonance structure in the total cross
section for the photodetachment of Li^-. The structure arises from the
autodetaching decay of doubly excited ^1P states of Li^- that are bound with
respect to the 3p state of the Li atom. Calculations have been performed for
both Li^- and H^- ... | physics |
8,824 | Output coupling for an atom laser by state change | physics.atom-ph | We calculate the spectrum of a beam of atoms output from a single mode atomic
cavity. The output coupling uses an internal state change to an untrapped
state. We present an analytical solution for the output energy spectrum from a
broadband coupler of this type. An example of such an output coupler, which we
discuss in... | physics |
8,825 | Two-body effects in the decay rate of atomic levels | physics.atom-ph | Recoil corrections to the atomic decay rate are considered in the order of
Zm/M . The expressions are treated exactly without any expansion over Z alpha.
The expressions obtained are valid both for muonic atoms (for which they
contribute on the level of a few percent in high Z ions) and for electronic
atoms. Explicit r... | physics |
8,826 | Post-Collision Interaction with Wannier electrons | physics.atom-ph | A theory of the Post-Collision Interaction (PCI) is developed for the case
when an electron atom impact results in creation of two low-energy Wannier
electrons and an ion excited into an autoionizing state. The following
autoionization decay exposes the Wannier pair to the influence of PCI resulting
in variation of the... | physics |
8,827 | Evolution and global collapse of trapped Bose condensates under variations of the scattering length | physics.atom-ph | We develop the idea of selectively manipulating the condensate in a trapped
Bose-condensed gas, without perturbing the thermal cloud. The idea is based on
the possibility to modify the mean field interaction between atoms (scattering
length) by nearly resonant incident light or by spatially uniform change of the
trappi... | physics |
8,828 | Low-energy elementary excitations of a trapped Bose-condensed gas | physics.atom-ph | Bogolyubov-De Gennes equations for the excitations of a Bose condensate in
the Thomas-Fermi regime in harmonic traps of any asymmetry and introduce a
classification of eigenstates. In the case of cylindrical symmetry we emphasize
the presence of an accidental degeneracy in the excitation spectrum at certain
values of t... | physics |
8,829 | Stark quenching for the $1s^22s2p^3P_0$ level in beryllium-like ions and parity-violating effects | physics.atom-ph | In this paper we present some concepts in heavy ion atomic physics for the
extraction of parity violating effects. We investigate the effects of the
so-called Stark-quenching, i.e., the fast decay of a meta stable state induced
by a Stark field, and the superposition of one- and two-photon transitions in
beryllium-like... | physics |
8,830 | The distorted-wave impulse approximation for electron capture into excited states | physics.atom-ph | Total cross sections for electron capture are calculated for collisions of
fast protons and alpha-particles with atomic hydrogen. The distorted- wave
impulse approximation is applied over the energy range 10-1500 keV/u.
State-selective results are given for the 1s, 2s and 2p levels. Both the 'post'
and 'prior' forms of... | physics |
8,831 | Self-energy correction to the hyperfine structure splitting of the 1s and 2s states in hydrogenlike ions | physics.atom-ph | The one-loop self-energy correction to the hyperfine structure splitting of
the 1s and 2s states of hydrogenlike ions is calculated both for the point and
finite nucleus. The results of the calculation are combined with other
corrections to find the ground state hyperfine splitting in lithiumlike
^{209}Bi^{80+} and ^{1... | physics |
8,832 | QED theory of the nuclear recoil effect in atoms | physics.atom-ph | The quantum electrodynamic theory of the nuclear recoil effect in atoms to
all orders in \alpha Z is formulated. The nuclear recoil corrections for atoms
with one and two electrons over closed shells are considered in detail. The
problem of the composite nuclear structure in the theory of the nuclear recoil
effect is d... | physics |
8,833 | Enhancement of the electric dipole moment of the electron in the YbF molecule | physics.atom-ph | We calculate an effective electric field on the unpaired electron in the YbF
molecule. This field determines sensitivity of the molecular experiment to the
electric dipole moment of the electron. We use experimental value of the
spin-doubling constant to estimate the admixture of the configuration with the
hole in the ... | physics |
8,834 | Second-order magnetic contributions to the hyperfine splitting of the 5snd ^1D_2 states in ^87Sr | physics.atom-ph | The hyperfine structure of 5snd ^1D_2 states in ^{87}Sr was studied for
principal quantum numbers 11 <= n <= 25 by Doppler-free two-photon excitation
combined with thermionic detection. Based on the more accurate data, compared
to previous results, the hyperfine structure was analysed by second order
perturbation theor... | physics |
8,835 | Two electron dynamics in photodetachment | physics.atom-ph | We present the results of experimental studies of photon-negative ion
interactions involving the dynamics of two electrons. Resonances associated
with doubly excited states of Li^- and He^- have been observed using laser
photodetachment spectroscopy. Total and partial photodetachment cross sections
have been investigat... | physics |
8,836 | Recoil Correction to Hydrogen Energy Levels: A Revision | physics.atom-ph | Recent calculations of the order (Z\alpha)^4(m/M)Ry pure recoil correction to
hydrogen energy levels are critically revised. The origins of errors made in
the previous works are elucidated. In the framework of a successive approach,
we obtain the new result for the correction to S levels. It amounts to -16.4
kHz in the... | physics |
8,837 | The bound mu+ mu- system | physics.atom-ph | We consider the hyperfine structure, the atomic spectrum and the decay
channels of the bound mu+ mu- system (dimuonium). The annihilation lifetimes of
low-lying atomic states of the system lie in the nanosecond range range. The
decay rates could be measured by detection of the decay products (high energy
photons or ele... | physics |
8,838 | Ground state hyperfine splitting of high Z hydrogenlike ions | physics.atom-ph | The ground state hyperfine splitting values of high Z hydrogenlike ions are
calculated. The relativistic, nuclear and QED corrections are taken into
account. The nuclear magnetization distribution correction (the Bohr-Weisskopf
effect) is evaluated within the single particle model with the g_{S}-factor
chosen to yield ... | physics |
8,839 | Strong nonlinear regime of resonant four-wave mixing in a gas | physics.atom-ph | The explicit solution is obtained for Raman four-wave mixing
$\omega_4=\omega_1-\omega_2+\omega_3$ of two strong fields $E_1, E_3$ and two
weak fields $E_2, E_4$ in a four-level system with the large Doppler
broadening. The resonance of the mixing coefficient vs intensity is found near
equal Rabi frequencies of strong ... | physics |
8,840 | Model for Trapped Ion interacting with Standing Wave | physics.atom-ph | We treat the interaction of a trapped ion with a standing-wave light field
relaxing the previous condition of the trapping ion being on the node of the
standing wave. In addition we work to second order in the Lamb-Dicke parameter
$\eta$, the extension to higher orders in $\eta$ is also indicated. Only a
simple transfo... | physics |
8,841 | Transition energy and lifetime for the ground state hyperfine splitting of high Z lithiumlike ions | physics.atom-ph | The ground state hyperfine splitting values and the transition probabilities
between the hyperfine structure components of high Z lithiumlike ions are
calculated in the range $Z=49-83$. The relativistic, nuclear, QED and
interelectronic interaction corrections are taken into account. It is found
that the Bohr-Weisskopf... | physics |
8,842 | Two-electron self-energy contribution to the ground state energy of heliumlike ions | physics.atom-ph | The two-electron self-energy contribution to the ground state energy of
heliumlike ions is calculated both for a point nucleus and an extended nucleus
in a wide interval of Z. All the two-electron contributions are compiled to
obtain most accurate values for the two-electron part of the ground state
energy of heliumlik... | physics |
8,843 | Quantum and Semiclassical Calculations of Cold Atom Collisions in Light Fields | physics.atom-ph | We derive and apply an optical Bloch equation (OBE) model for describing
collisions of ground and excited laser cooled alkali atoms in the presence of
near-resonant light. Typically these collisions lead to loss of atoms from
traps. We compare the results obtained with a quantum mechanical complex
potential treatment, ... | physics |
8,844 | On doubly excited states in negative ions | physics.atom-ph | Atomic negative ions are fragile quantum systems in which correlation among
the valence electrons plays a very important role. For doubly excited states
correlation becomes dominant. Photodetachment is the process where a negative
ion absorbs a photon and as a consquence ejects the outermost electron. A new
detection s... | physics |
8,845 | X-ray emission during the muonic cascade in hydrogen | physics.atom-ph | We report our investigations of X rays emitted during the muonic cascade in
hydrogen employing charge coupled devices as X-ray detectors. The density
dependence of the relative X-ray yields for the muonic hydrogen lines (K_alpha,
K_beta, K_gamma) has been measured at densities between 0.00115 and 0.97 of
liquid hydroge... | physics |
8,846 | Excited State Muon Transfer in Hydrogen/Deuterium Mixtures | physics.atom-ph | We report the first direct observation of excited state muon transfer in
hydrogen/deuterium mixtures by direct measurement of q_1s, the probability that
a mu-p atom, which is initially formed in an excited state, reaches the 1s
ground state. The dependence of q_1s on deuterium concentration c_d was
measured for two dif... | physics |
8,847 | The Hilbert-Schmidt Theorem Formulation of the R-Matrix Theory | physics.atom-ph | Using the Hilbert-Schmidt theorem, we reformulate the R-matrix theory in
terms of a uniformly and absolutely convergent expansion. Term by term
differentiation is possible with this expansion in the neighborhood of the
surface. Methods for improving the convergence are discussed when the
R-function series is truncated ... | physics |
8,848 | Infinite Order Discrete Variable Representation for Quantum Scattering | physics.atom-ph | A new approach to multi-dimensional quantum scattering by the infinite order
discrete variable representation is presented. Determining the expansion
coefficients of the wave function at the asymptotic regions by the solution of
the differential Schr\"{o}dinger equation, we reduce an infinite set of linear
equations to... | physics |
8,849 | Recoil correction to the ground state energy of hydrogenlike atoms | physics.atom-ph | The recoil correction to the ground state energy of hydrogenlike atoms is
calculated to all orders in \alpha Z in the range Z = 1-110. The nuclear size
corrections to the recoil effect are partially taken into account. In the case
of hydrogen, the relativistic recoil correction beyond the Salpeter
contribution and the ... | physics |
8,850 | Extended Classical Over-Barrier Model for Collisions of Highly Charged Ions with Conducting and Insulating Surfaces | physics.atom-ph | We have extended the classical over-barrier model to simulate the
neutralization dynamics of highly charged ions interacting under grazing
incidence with conducting and insulating surfaces. Our calculations are based
on simple model rates for resonant and Auger transitions. We include effects
caused by the dielectric r... | physics |
8,851 | Interactions of Ar(9+) and metastable Ar(8+) with a Si(100) surface at velocities near the image acceleration limit | physics.atom-ph | Auger LMM spectra and preliminary model simulations of Ar(9+) and metastable
Ar(8+) ions interacting with a clean monocrystalline n-doped Si(100) surface
are presented. By varying the experimental parameters, several yet undiscovered
spectroscopic features have been observed providing valuable hints for the
development... | physics |
8,852 | Signature of metastable electrons in highly charged ion surface interactions | physics.atom-ph | We present autoionization spectra of metastable Ar(8+) and C(4+), N(5+),
O(6+) and Ne(8+) scattering off an Al(111) surface with incident energies down
to 5 eV. The unprecedented quality of the experimental data permits the
observation of a unique, yet undiscovered peak in the structures originating
from the metastable... | physics |
8,853 | Positronium in crossed electric and magnetic fields: the existence of a long-lived ground state | physics.atom-ph | It was earlier reported [PRL 78 199, (1997)] that long-lived excited states
of positronium can be formed in crossed electric and magnetic fields at
laboratory field strengths. Unlike the lower-lying states that are localized in
the magnetically distorted Coulomb well, these long-lived states which can
possess a lifetim... | physics |
8,854 | Electron detachment from negative ions in bichromatic laser field | physics.atom-ph | Negative ion detachment in two-colour laser field is considered within the
recent modification of Keldysh model which makes it quantitatively reliable.
The general approach is illustrated by calculation of angular differential
detachment rates, partial rates for particular ATD (Above Threshold Detachment)
channels and ... | physics |
8,855 | A two-dimensional, two-electron model atom in a laser pulse: exact treatment, single active electron-analysis, time-dependent density functional theory, classical calculations, and non-sequential ionization | physics.atom-ph | Owing to its numerical simplicity, a two-dimensional two-electron model atom,
with each electron moving in one direction, is an ideal system to study
non-perturbatively a fully correlated atom exposed to a laser field. Frequently
made assumptions, such as the ``single active electron''- approach and
calculational appro... | physics |
8,856 | The ground state of the Lithium atom in strong magnetic fields | physics.atom-ph | The ground and some excited states of the Li atom in external uniform
magnetic fields are calculated by means of our 2D mesh Hartree-Fock method for
field strengths ranging from zero up to 2.35 10^8 T. With increasing field
strength the ground state undergoes two transitions involving three different
electronic configu... | physics |
8,857 | Photodetachment study of He^- quartet resonances below the He(n=3) thresholds | physics.atom-ph | The photodetachment cross section of He^- has been measured in the photon
energy range 2.9 eV to 3.3 eV in order to investigate doubly excited states.
Measurements were made channel specific by selectively detecting the residual
He atoms left in a particular excited state following detachment. Three
Feshbach resonances... | physics |
8,858 | Stark-Induced Electric Dipole Amplitudes for Hyperfine Transitions | physics.atom-ph | Stark-induced electric dipole amplitudes between states of the same nominal
parity can be important in experiments to observe parity nonconservation in
atoms. The Stark-induced E1 amplitudes are expressed in terms of an irreducible
spherical-tensor decomposition. This formalism is applied to the specific case
of transi... | physics |
8,859 | The steady state of a pumped and damped atom laser | physics.atom-ph | This paper has been withdrawn, as further work has shown that an atom laser
as described by the model herein does not have a steady state, so it doesn't
matter much what it would look like. | physics |
8,860 | Exact field ionization rates in the barrier suppression-regime from numerical TDSE calculations | physics.atom-ph | Numerically determined ionization rates for the field ionization of atomic
hydrogen in strong and short laser pulses are presented. The laser pulse
intensity reaches the so-called "barrier suppression ionization" regime where
field ionization occurs within a few half laser cycles. Comparison of our
numerical results wi... | physics |
8,861 | Wei Hua's Four Parameter Potential Comments and Computation of Moleculer Constants α_e and ω_e x_e | physics.atom-ph | The value of adjustable parameter $C$ and the four-parameter potential $U(r)
= D_{e}\left [ \frac{1-{exp}[-b(r-r_{e})]}{1-C{exp} [-b(r-r_{e})]} \right
]^{2}$ has been expressed in terms of molecular parameters and its significance
has been brought out. The potential so constructed, with $C$ derived from the
molecular p... | physics |
8,862 | Atoms in static fields: Chaos or Diffraction? | physics.atom-ph | A brief review of the manifestations of classical chaos observed in atomic
systems is presented. Particular attention is paid to the analysis of atomic
spectra by periodic orbit-type theories. For diamagnetic non-hydrogenic Rydberg
atoms, the dynamical explanation for observed spectral features has been
disputed. By bu... | physics |
8,863 | Threshold Laws for the Break-up of Atomic Particles into Several Charged Fragments | physics.atom-ph | The processes with three or more charged particles in the final state exhibit
particular threshold behavior, as inferred by the famous Wannier law for (2e +
ion) system. We formulate a general solution which determines the threshold
behavior of the cross section for multiple fragmentation. Applications to
several syste... | physics |
8,864 | Isotope shift in the electron affinity of chlorine | physics.atom-ph | The specific mass shift in the electron affinity between ^{35}Cl and ^{37}Cl
has been determined by tunable laser photodetachment spectroscopy to be
-0.51(14) GHz. The isotope shift was observed as a difference in the onset of
the photodetachment process for the two isotopes. In addition, the electron
affinity of Cl wa... | physics |
8,865 | Raman cooling of atoms below the gravitational limit | physics.atom-ph | Raman cooling of non-zero-spin atoms in the presence of gravitational and
external magnetic fields is investigated. The magnetic field is adjusted so as
to compensate for the gravitational force acting on ground-state atoms. The
dark state (DS) is created and supported in momentum space with additional
velocity-selecti... | physics |
8,866 | Deduction of the quantum unmbers of low-lying states of the (e+e+e-e-) system from symmetry consideration | physics.atom-ph | The feature of the low-lying spectrum and a complete set of quantum numbers
of the (e+e+e-e-) system have been deduced based on symmetry consideration. The
existence of a low odd-parity L=1 excited state with the spins of the two
electrons coupled to s1=1 and the two positrons coupled to s2=0 (or s1=0 and
s2=1) and a l... | physics |
8,867 | Qualitative feature of the low-lying spectrum of intrashell states of 4-valence-electron atoms derived from symmetry consideration | physics.atom-ph | Inherent nodal surfaces existing in the wavefunctions of intrashell states of
4-valence-electron atoms have been investigated. The decisive effect of these
surfaces has been demonstrated, the ordering of low-lying levels has been
predicted, a primary classification scheme has been proposed, the existence of
three rotat... | physics |
8,868 | Measurement of the Muonium 1S-2S Transition Frequency | physics.atom-ph | A new measurement of the 1S-2S energy splitting of muonium by Doppler-free
two-photon spectroscopy has been performed at the Rutherford Appleton
Laboratory in Chilton, Didcot, UK. Increased accuracy is expected compared to a
previous experiment. Spectroscopy of this transistion promises an improvement
of the muon mass ... | physics |
8,869 | Antiproton-Hydrogen annihilation at sub-kelvin temperatures | physics.atom-ph | The main properties of the interaction of ultra low-energy antiprotons ($%
E\le10^{-6}$ a.u.) with atomic hydrogen are established. They include the
elastic and inelastic cross sections and Protonium (Pn) formation spectrum. The
inverse Auger process ($Pn+e \to H+\bar{p}$) is taken into account in the
framework of an u... | physics |
8,870 | Adiabatic stabilization of a circular state: theory compared to experiment | physics.atom-ph | The probability that an atom of hydrogen, initially in the 5g(m=4) state,
survives a 90-fs pulse of 620 nm wavelength is calculated both by direct
integration of the time-dependent Schroedinger equation and by a Floquet
calculation. The two methods give virtually identical results. The survival
probability calculated f... | physics |
8,871 | Atom cooling and trapping by disorder | physics.atom-ph | We demonstrate the possibility of three-dimensional cooling of neutral atoms
by illuminating them with two counterpropagating laser beams of mutually
orthogonal linear polarization, where one of the lasers is a speckle field,
i.e. a highly disordered but stationary coherent light field. This
configuration gives rise to... | physics |
8,872 | Qualitative analysis on the existence of bound excited states and low-lying resonances of the dipositronium | physics.atom-ph | Symmetry has imposed very strong constraints on the structures of internal
wave functions and on the accessibility of outgoing channels. Based on symmetry
consideration, the existence of a number of bound excited states and low-lying
resonances has been suggested. | physics |
8,873 | Limit on suppression of ionization in metastable neon traps due to long-range anisotropy | physics.atom-ph | This paper investigates the possibility of suppressing the ionization rate in
a magnetostatic trap of metastable neon atoms by spin-polarizing the atoms.
Suppression of the ionization is critical for the possibility of reaching
Bose-Einstein condensation with such atoms. We estimate the relevant long-range
interactions... | physics |
8,874 | A magnetic guide for cold atoms | physics.atom-ph | We propose a novel method for guiding cold, neutral atoms using static
magnetic fields. A theoretical study of the magnetic field produced by a tube
consisting of two identical, interwound solenoids carrying equal but opposite
currents is presented. This field is almost zero throughout the centre of the
tube, but it in... | physics |
8,875 | Nonadiabatic dynamics in evaporative cooling of trapped atoms by a radio frequency field | physics.atom-ph | Magnetically trapped neutral atoms can be cooled with the evaporation
technique. This is typically done by using a radiofrequency (rf) field that
adiabatically couples trapped and untrapped internal atomic states for atoms
with kinetic energies above a value set by the field frequency. The rf-field
can also induce nona... | physics |
8,876 | Comment on "Accurate relativistic effective potentials for the sixth-row main group elements" [J.Chem.Phys. 107, 9975 (1997)] | physics.atom-ph | Critical remarks in respect to the Generalized Relativistic Effective Core
Potential in the recent article of S.A.Wildman at al. are discussed and shown
to be incorrect. | physics |
8,877 | Resonant magnetic field control of elastic scattering of cold 85Rb | physics.atom-ph | A magnetic field dependent Feshbach resonance has been observed in the
elastic scattering collision rate between atoms in the F = 2, M = -2 state of
85 Rb. Changing the magnetic field by several Gauss caused the collision rate
to vary by a factor of 10,000, and the sign of the scattering length could be
reserved. The r... | physics |
8,878 | Mesoscopic motion of atomic ions in magnetic fields | physics.atom-ph | We introduce a semiclassical model for moving highly excited atomic ions in a
magnetic field which allows us to describe the mixing of the Landau orbitals of
the center of mass in terms of the electronic excitation and magnetic field.
The extent of quantum energy flow in the ion is investigated and a crossover
from loc... | physics |
8,879 | Quantum chaos, statistical equilibrium and resonant radiative capture of electrons by multicharged ions: Au 24+ | physics.atom-ph | We show that the spectrum and eigenstates of open-shell multicharged atomic
ions near the ionization threshold are chaotic, as a result of extremely high
level densities of multiply excited electron states (1000 levels per eV in Au
24+) and a strong configuration mixing. This complexity enables one to use
statistical m... | physics |
8,880 | Soliton Model of Hydrogen Atom: Resonance Effects | physics.atom-ph | Some first principles that, we believe, could serve as foundation for quantum
theory of extended particles are formulated. It is also shown that in the
point-like particles limit the non-relativistic quantum mechanics can be
restored. As an illustration the soliton model of hydrogen atom is considered. | physics |
8,881 | Cold Collision Frequency Shift of the 1S-2S Transition in Hydrogen | physics.atom-ph | We have observed the cold collision frequency shift of the 1S-2S transition
in trapped spin-polarized atomic hydrogen. We find $\Delta \nu_{1S-2S} =
-3.8(8)\times 10^{-10} n Hz cm^3$, where $n$ is the sample density. From this
we derive the 1S-2S s-wave triplet scattering length, $a_{1S-2S}=-1.4(3)$ nm,
which is in fai... | physics |
8,882 | Bose-Einstein Condensation of Atomic Hydrogen | physics.atom-ph | We report observation of Bose-Einstein condensation of a trapped, dilute gas
of atomic hydrogen. The condensate and normal gas are studied by two-photon
spectroscopy of the 1S-2S transition. Interactions among the atoms produce a
shift of the resonance frequency proportional to density. The condensate is
clearly distin... | physics |
8,883 | Muonium | physics.atom-ph | The energy levels of the muonium ($\mu^+ e^-$) atom, which consists of two
''point-like'' leptonic particles, can be calculated to very high accuracy in
the framework of bound state Quantum Electrodynamics (QED), since there are no
complications due to internal nuclear structure and size which is the case for
all atoms... | physics |
8,884 | Observation of proximity resonances in a parallel-plate waveguide | physics.atom-ph | We have observed proximity resonances in a two dimensional system consisting
of dielectric scatterers in a parallel plate waveguide. A numerical solution to
the scattering problem supports the analysis of the experimental data. | physics |
8,885 | Calculation of hyperfine structure constants for ytterbium | physics.atom-ph | We calculate energies and hyperfine structure constants A and B for low-lying
levels of $^{173}$Yb. The latter is treated as a two-electron atom. To account
for valence-valence correlations the configuration interaction method is used.
Valence-core correlations are accounted for within the many-body perturbation
theory... | physics |
8,886 | Matter wave interference using two-level atoms and resonant optical fields | physics.atom-ph | A theory of matter wave interference is developed in which resonant optical
fields interact with two-level atoms. When recoil effects are included, spatial
modulation of the atomic density can occur for times that are greater than or
comparable with the inverse recoil frequency. In this regime, the atoms exhibit
matter... | physics |
8,887 | How to observe the Efimov effect | physics.atom-ph | We propose to observe the Efimov effect experimentally by applying an
external electric field on atomic three-body systems. We first derive the
lowest order effective two-body interaction for two spin zero atoms in the
field. Then we solve the three-body problem and search for the extreme
spatially extended Efimov stat... | physics |
8,888 | Quasiperiodic Atom Optics, Focusing, and Wave packet Rephasing | physics.atom-ph | We propose a laser field configuration which acts as a quasiperiodic atom
optical diffraction grating. Analytical and computational results for the
atomic center-of-mass wavefunction after the grating reveal a quasiperiodic
density pattern, a semiclassical focusing effect, and a quasiperiodic
self-imaging of the atomic... | physics |
8,889 | Threshold detachment of negative ions by electron impact | physics.atom-ph | The description of threshold fragmentation under long range repulsive forces
is presented. The dominant energy dependence near threshold is isolated by
decomposing the cross section into a product of a back ground part and a
barrier penetration probability resulting from the repulsive Coulomb
interaction. This tunnelin... | physics |
8,890 | Geometrical Realization of Beutler-Fano formulas appearing in eigenphase shifts and time delays in multichannel scattering | physics.atom-ph | Recently, we showed that eigenphase shifts and eigentime delays near a
resonance for a system of one discrete state and two continua are functionals
of the Beutler-Fano formula using appropriate dimensionless energy units and
line profile indices and identified parameters responsible for the avoided
crossing of eigenph... | physics |
8,891 | Identification of the Beutler-Fano formula in eigenphase shifts and eigentime delays near a resonance | physics.atom-ph | Eigenphase shifts and eigentime delays near a resonance for a system of one
discrete state and two continua are shown to be functionals of the Beutler-
Fano formulas using appropriate dimensionless energy units and line profile
indices. Parameters responsible for the avoided crossing of eigenphase shifts
and eigentime ... | physics |
8,892 | Enhancement factor for the electron electric dipole moment in francium and gold atoms | physics.atom-ph | If electrons had an electric dipole moment (EDM) they would induce EDMs of
atoms. The ratio of the atomic EDM to the electron EDM for a particular atom is
called the enhancement factor, R. We calculate the enhancement factor for the
francium and gold atoms, with the results 910 plus/minus 5% for Fr and 260
plus/minus 1... | physics |
8,893 | Ionization dynamics in intense pulsed laser radiation. Effects of frequency chirping | physics.atom-ph | Via a non-perturbative method we study the population dynamics and
photoelectron spectra of Cs atoms subject to intense chirped laser pulses, with
gaussian beams. We include above threshold ionization spectral peaks. The
frequency of the laser is near resonance with the 6s-7p transition. Dominant
couplings are included... | physics |
8,894 | Adiabatic Theory of Electron Detachment from Negative Ions in Two-Color Laser Field | physics.atom-ph | Negative ion detachment in bichromatic laser field is considered within the
adiabatic theory. The latter represents a recent modification of the famous
Keldysh model for multiphoton ionization which makes it quantitatively
reliable. We calculate angular differential detachment rates, partial rates for
particular ATD (A... | physics |
8,895 | High-precision calculations of dispersion coefficients, static dipole polarizabilities, and atom-wall interaction constants for alkali-metal atoms | physics.atom-ph | The van der Waals coefficients for the alkali-metal atoms from Na to Fr
interacting in their ground states, are calculated using relativistic ab initio
methods. The accuracy of the calculations is estimated by also evaluating
atomic static electric dipole polarizabilities and coefficients for the
interaction of the ato... | physics |
8,896 | Pair correlation function of an inhomogeneous interacting Bose-Einstein condensate | physics.atom-ph | We calculate the pair correlation function of an interacting Bose gas in a
harmonic trap directly via Path Integral Quantum Monte Carlo simulation for
various temperatures and compare the numerical result with simple approximative
treatments. Around the critical temperature of Bose-Einstein condensation, a
description ... | physics |
8,897 | Relativistic dynamical polarizability of hydrogen-like atoms | physics.atom-ph | Using the operator representation of the Dirac Coulomb Green function the
analytical method in perturbation theory is employed in obtaining solutions of
the Dirac equation for a hydrogen-like atom in a time-dependent electric field.
The relativistic dynamical polarizability of hydrogen-like atoms is calculated
and anal... | physics |
8,898 | Bose-Einstein Condensation of Atomic Hydrogen | physics.atom-ph | We have observed Bose-Einstein condensation (BEC) of trapped atomic hydrogen,
and studied it by two-photon spectroscopy of the 1S-2S transition. In these
lecture notes we briefly review the history of spin-polarized atomic hydrogen
and describe the final steps to BEC. Laser spectroscopy, which probes the
difference in ... | physics |
8,899 | Photoionization Suppression by Continuum Coherence: Experiment and Theory | physics.atom-ph | We present experimental and theoretical results of a detailed study of
laser-induced continuum structures (LICS) in the photoionization continuum of
helium out of the metastable state 2s $^1S_0$. The continuum dressing with a
1064 nm laser, couples the same region of the continuum to the {4s $^1S_0$}
state. The experim... | physics |
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