29,512 research outputs found
New magic number for neutron rich Sn isotopes
The variation of E(2+_1) of (134-140)Sn calculated with empirical SMPN
interaction has striking similarity with that of experimental E(2+_1) of
even-even (18-22)O and (42-48)Ca, showing clearly that N=84-88 spectra exhibit
the effect of gradual filling up of \nu(2f_{7/2}) orbital which finally
culminates in a new shell closure at N=90. Realistic two-body interaction CWG
does not show this feature. Spin-tensor decomposition of SMPN and CWG
interactions and variation of their components with valence neutron number
reveals that the origin of the shell closure at 140Sn lies in the three body
effects. Calculations with CWG3, which is obtained by including a simple
three-body monopole term in the CWG interaction, predict decreasing E(2+_1) for
(134-138)Sn and a shell closure at 140Sn.Comment: 4 pages, 5 figure
Holographic bulk reconstruction beyond (super)gravity
We outline a holographic recipe to reconstruct corrections to AdS
(quantum) gravity from an underlying CFT in the strictly planar limit
(). Assuming that the boundary CFT can be solved in
principle to all orders of the 't Hooft coupling , for scalar primary
operators, the expansion of the conformal dimensions can be
mapped to higher curvature corrections of the dual bulk scalar field action.
Furthermore, for the metric pertubations in the bulk, the AdS/CFT
operator-field isomorphism forces these corrections to be of the Lovelock type.
We demonstrate this by reconstructing the coefficient of the leading Lovelock
correction, aka the Gauss-Bonnet term in a bulk AdS gravity action using the
expression of stress-tensor two-point function up to sub-leading order in
.Comment: 19 pages, typos corrected, published version (journal version title
is different
Optimal coupling of entangled photons into single-mode optical fibers
We present a consistent multimode theory that describes the coupling of
single photons generated by collinear Type-I parametric down-conversion into
single-mode optical fibers. We have calculated an analytic expression for the
fiber diameter which maximizes the pair photon count rate. For a given focal
length and wavelength, a lower limit of the fiber diameter for satisfactory
coupling is obtained
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