1,302 research outputs found
Incorporation of three-nucleon force in the effective interaction hyperspherical harmonic approach
It is shown how a bare three-nucleon force is incorporated into the formalism
of the effective interaction approach for hyperspherical harmonics. As a
practical example we calculate the ground state properties of 3H and 3He using
the Argonne V18 nucleon-nucleon potential and the Urbana IX three-nucleon
force. A very good convergence of binding energies and matter radii is
obtained. We also find a very good agreement of our results compared to other
high precision calculations.Comment: 17 pages, 3 figure
Improved (e,e') response functions at intermediate momentum transfers: the 3He case
A possibility of extending the applicability range of non-relativistic
calculations of electronuclear response functions in the quasielasic peak
region is studied. We show that adopting a particular model for determining the
kinematical inputs of the non-relativistic calculations can extend this range
considerably, almost eliminating the reference frame dependence of the results.
We also show that there exists one reference frame, where essentially the same
result can be obtained with no need of adopting the particular kinematical
model. The calculation is carried out with the Argonne V18 potential and the
Urbana IX three-nucleon interaction. A comparison of these improved
calculations with experimental data shows a very good agreement for the
quasielastic peak positions at 600, 700 MeV/c and for the peak heights
at the two lower --values, while for the peak height at MeV/c one
finds differences of about 20%.Comment: 10 pages, 4 figure
Optimisation of two-dimensional ion trap arrays for quantum simulation
The optimisation of two-dimensional (2D) lattice ion trap geometries for
trapped ion quantum simulation is investigated. The geometry is optimised for
the highest ratio of ion-ion interaction rate to decoherence rate. To calculate
the electric field of such array geometries a numerical simulation based on a
"Biot-Savart like law" method is used. In this article we will focus on square,
hexagonal and centre rectangular lattices for optimisation. A method for
maximising the homogeneity of trapping site properties over an array is
presented for arrays of a range of sizes. We show how both the polygon radii
and separations scale to optimise the ratio between the interaction and
decoherence rate. The optimal polygon radius and separation for a 2D lattice is
found to be a function of the ratio between rf voltage and drive frequency
applied to the array. We then provide a case study for 171Yb+ ions to show how
a two-dimensional quantum simulator array could be designed
The Lorentz integral transform (LIT) method
The LIT approach is reviewed both for inclusive and exclusive reactions. It
is shown that the method reduces a continuum state problem to a
bound-state-like problem, which then can be solved with typical bound-state
techniques. The LIT approach opens up the possibility to perform ab initio
calculations of reactions also for those particle systems which presently are
out of reach in conventional approaches with explicit calculations of many-body
continuum wave functions. Various LIT applications are discussed ranging from
particle systems with two nucleons up to particle systems with seven nucleons.Comment: Lectures delivered at the 4th DAE-BRNS Workshop on Hadron Physics,
AMU, Aligarh, India, Feb. 18-23, 2008; 23 pages, 16 figure
Versatile ytterbium ion trap experiment for operation of scalable ion-trap chips with motional heating and transition-frequency measurements
We present the design and operation of an ytterbium ion trap experiment with a setup offering versatile optical access and 90 electrical interconnects that can host advanced surface and multilayer ion trap chips mounted on chip carriers. We operate a macroscopic ion trap compatible with this chip carrier design and characterize its performance, demonstrating secular frequencies >1 MHz, and trap and cool nearly all of the stable isotopes, including 171Yb+ ions, as well as ion crystals. For this particular trap we measure the motional heating rate â©nÌâȘ and observe an â©nÌâȘâ1/Ï2 behavior for different secular frequencies Ï. We also determine a spectral noise density SE(1âMHz)=3.6(9)Ă10-11 V2 m-2 Hz-1 at an ion electrode spacing of 310(10) ÎŒm. We describe the experimental setup for trapping and cooling Yb+ ions and provide frequency measurements of the 2S1/2â2P1/2 and 2D3/2â3D[3/2]1/2 transitions for the stable 170Yb+, 171Yb+, 172Yb+, 174Yb+, and 176Yb+ isotopes which are more precise than previously published work
Test of J-matrix inverse scattering potentials on electromagnetic reactions of few-nucleon systems
The J-matrix inverse scattering nucleon-nucleon potentials (JISP), describing
both two-nucleon data and bound and resonant states of light nuclei to high
accuracy, are tested on the total photoabsorption cross sections of Deuteron,
Triton, 3He and 4He. The calculations in the three- and four-body systems are
carried out via the Lorentz integral transform method and the hyperspherical
harmonics (HH) technique. To this end the HH formalism has been adapted to
accommodate non-local potentials. The cross sections calculated with the JISP
are compared to those obtained with more traditional realistic interactions,
which include two- and three-nucleon forces. While the results of the two kinds
of potential models do not differ significantly at lower energies, beyond the
resonance peak they show fairly large discrepancies, which increase with the
nuclear mass. We argue that these discrepancies may be due to a probably
incorrect long range behavior of the JISP, since the one pion exchange is not
manifestly implemented there.Comment: 18 pages, 4 figures, 1 tabl
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