2,878 research outputs found
Fast and dense magneto-optical traps for Strontium
We improve the efficiency of sawtooth-wave-adiabatic-passage (SWAP) cooling
for strontium atoms in three dimensions and combine it with standard
narrow-line laser cooling. With this technique, we create strontium
magneto-optical traps with bosonic Sr (
fermionic Sr) atoms at phase-space densities of
(). Our method is simple to implement and is faster and more
robust than traditional cooling methods.Comment: 9 pages, 6 figure
Experimental proposal for accurate determination of the phase relaxation time and testing a formation of thermalized non-equilibrated matter in highly excited quantum many-body systems
We estimate how accurate the phase relaxation time of quantum many-body
systems can be determined from data on forward peaking of evaporating protons
from a compound nucleus. The angular range and accuracy of the data needed for
a reliable determination of the phase relaxation time are evaluated. The
general method is applied to analyze the inelastic scattering of 18 MeV protons
from Pt for which previously measured double differential cross sections for
two angles in the evaporating domain of the spectra show a strong forward
peaking. A new experiment for an improved determination of the phase relaxation
time is proposed. The experiment is also highly desirable for an accurate test
of a formation of thermalized non-equilibrated matter in quantum many-body
systems.Comment: 5 pages, 3 figure
Effective-range approach and scaling laws for electromagnetic strength in neutron-halo nuclei
We study low-lying multipole strength in neutron-halo nuclei. The strength
depends only on a few low-energy constants: the neutron separation energy, the
asymptotic normalization coefficient of the bound state wave function, and the
scattering length that contains the information on the interaction in the
continuum. The shape of the transition probability shows a characteristic
dependence on few scaling parameters and the angular momenta. The total E1
strength is related to the root-mean-square radius of the neutron wave function
in the ground state and shows corresponding scaling properties. We apply our
approach to the E1 strength distribution of 11Be.Comment: 4 pages, 1 figure (modified), additional table, extended discussion
of example, accepted for publication in Phys. Rev. Let
Systematic study of Optical Feshbach Resonances in an ideal gas
Using a narrow intercombination line in alkaline earth atoms to mitigate
large inelastic losses, we explore the Optical Feshbach Resonance (OFR) effect
in an ultracold gas of bosonic Sr. A systematic measurement of three
resonances allows precise determinations of the OFR strength and scaling law,
in agreement with coupled-channels theory. Resonant enhancement of the complex
scattering length leads to thermalization mediated by elastic and inelastic
collisions in an otherwise ideal gas. OFR could be used to control atomic
interactions with high spatial and temporal resolution.Comment: Significant changes to text and figure presentation to improve
clarity. Extended supplementary material. 4 pages, 4 figures; includes
supplementary material 8 pages, 4 figures. Submitted to Physical Review
Letter
State-Dependent Optical Lattices for the Strontium Optical Qubit
We demonstrate state-dependent optical lattices for the Sr optical qubit at
the tune-out wavelength for its ground state. We tightly trap excited state
atoms while suppressing the effect of the lattice on ground state atoms by more
than four orders of magnitude. This highly independent control over the qubit
states removes inelastic excited state collisions as the main obstacle for
quantum simulation and computation schemes based on the Sr optical qubit. Our
results also reveal large discrepancies in the atomic data used to calibrate
the largest systematic effect of Sr optical lattice clocks.Comment: 6 pages, 4 figures + 6 pages supplemental materia
Conductance peaks in open quantum dots
We present a simple measure of the conductance fluctuations in open ballistic
chaotic quantum dots, extending the number of maxima method originally proposed
for the statistical analysis of compound nuclear reactions. The average number
of extreme points (maxima and minima) in the dimensionless conductance, , as
a function of an arbitrary external parameter , is directly related to the
autocorrelation function of . The parameter can be associated to an
applied gate voltage causing shape deformation in quantum dot, an external
magnetic field, the Fermi energy, etc.. The average density of maxima is found
to be , where is a universal constant
and is the conductance autocorrelation length, which is system specific.
The analysis of does not require large statistic samples,
providing a quite amenable way to access information about parametric
correlations, such as .Comment: 5 pages, 5 figures, accepted to be published - Physical Review
Letter
Nonequilibrium Response from the dissipative Liouville Equation
The problem of response of nonequilibrium systems is currently under intense
investigation. We propose a general method of solution of the Liouville
Equation for thermostatted particle systems subjected to external forces which
retains only the slow degrees of freedom, by projecting out the majority of
fast variables. Response formulae, extending the Green-Kubo relations to
dissipative dynamics are provided, and comparison with numerical data is
presented
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