Towards Heisenberg Limit in Magnetometry with Parametric Down Converted Photons

Recent theoretical and experimental papers have shown how one can achieve Heisenberg limited measurements by using entangled photons. Here we show how the photons in non-collinear down conversion process can be used for improving the sensitivity of magneto-optical rotation by a factor of four which takes us towards the Heisenberg limit. Our results apply to sources with arbitrary pumping. We also present several generalizations of earlier results for the collinear geometry. The sensitivity depends on whether the two-photon or four-photon coincidence detection is used.Comment: 4.2 pages, 6 figure

Photon-Photon Correlations as a Probe of Vacuum Induced Coherence Effects

We present new experimental implications of the effects of vacuum induced coherence on the photon -photon correlation in the pi-polarized fluorescence in j = 1/2 to j = 1/2 transition. These effects should be thus observable in measurements of photon statistics in for example Hg and Ba ion traps.Comment: 7 pages, 6 figures, submitted to Physical Review

Incremental and Decremental Maintenance of Planar Width

We present an algorithm for maintaining the width of a planar point set dynamically, as points are inserted or deleted. Our algorithm takes time O(kn^epsilon) per update, where k is the amount of change the update causes in the convex hull, n is the number of points in the set, and epsilon is any arbitrarily small constant. For incremental or decremental update sequences, the amortized time per update is O(n^epsilon).Comment: 7 pages; 2 figures. A preliminary version of this paper was presented at the 10th ACM/SIAM Symp. Discrete Algorithms (SODA '99); this is the journal version, and will appear in J. Algorithm

Reanalysis of Agelietti Procedure (A Method of Corrective Supracondylar Femoral Osteotomy)

Objective: Supracondylar femoral osteotomy is the time tested method, used for correcting the angular (varus & valgus) deformities at the knee. Traditionally, Coventry type of osteotomy where a medial or lateral based wedge of bone is removed or an open wedge osteotomy is made & the space filled with bone graft, is done to achieve the desired correction. This osteotomy is subsequently stabilized with Kirschner wires or plates & screws. Later the limb is externally supported in brace or plaster cast. Here we present a case series of 10 cases, where we have analyzed the efficacy of Aglietti procedure, as a method of femoral supracondylar osteotomy for correcting the valgus deformity at the knee. Methods: Ten valgus adolescent knees were operated in 7 patients by following the Aglietti procedure for correcting the angular deformity at the knee. The results were analyzed taking into consideration the operating time, blood loss during surgery estimated by the number of surgical mops used, stability of the osteotomy in the post-operative period & ultimate range of motion (ROM) obtained at the end of 6 months after the surgery. Results: The average age of patients dealt with was 12.6 years (n=7) with females predominating (n=5) against 2 males. The average time was 47.5 minutes. The average size of the surgical mops used was 15x20 cms. Surgical mops used per patient were 1.6. The average range of flexion achieved at the end of 6 months after surgery was 131.45 degrees ( Rounded average to a measurable value being 131 degrees). Conclusion: In our case series we found Aglietti procedure as an effective method to correct the valgus deformity in adolescent knees. Supracondylar femoral osteotomies are not only for varus an valgus corrections; this osteotomy is used as well for rotation correction and flexion and extension correction, mainly in CP patients. But we used the Agelietti procedure for the correction of angular deformities(varus/valgus) in patients of nutritional rickets. However more number of cases need to be done to make a final conclusion of establishing the superiority of this method over other methods

On dimensional reduction of 4d N=1 Lagrangians for Argyres-Douglas theories

Recently, it was found that certain 4d $\mathcal{N}=1$ Lagrangians experience supersymmetry enhancement at their IR fixed point, thereby giving a Lagrangian description for a plethora of Argyres-Douglas theories. A generic feature of these Lagrangians is that a number of gauge invariant operators decouple (as free fields) along the RG-flow. These decoupled operators can be naturally taken into account from the beginning itself by introducing additional gauge singlets (sometimes called `flipping fields') that couple to the decoupled operators via appropriate superpotential terms. It has also been checked that upon dimensionally reducing to 3d, the $(A_1,A_{2n-1})$ type Lagrangians only produce the expected behavior when flipping fields are included in the Lagrangian. In this paper we further investigate the role of flipping fields and find an example where the expected necessity of including the flipping fields in the dimensionally reduced Lagrangians seems to get violated. In the process we find two new dual Lagrangians for the so called 3d $T[SU(2)]$ theory.Comment: v1: 26 pages, 7 figures ; v2: Minor typos corrected; v3: Corrected typos and other minor errors, added a discussion section to highlight the subtle but very important role played by accidental symmetries in this set-u