Atom Lithography with Near-Resonant Light Masks: Quantum Optimization Analysis

We study the optimal focusing of two-level atoms with a near resonant standing wave light, using both classical and quantum treatments of the problem. Operation of the focusing setup is considered as a nonlinear spatial squeezing of atoms in the thin- and thick-lens regimes. It is found that the near-resonant standing wave focuses the atoms with a reduced background in comparison with far-detuned light fields. For some parameters, the quantum atomic distribution shows even better localization than the classical one. Spontaneous emission effects are included via the technique of quantum Monte Carlo wave function simulations. We investigate the extent to which non-adiabatic and spontaneous emission effects limit the achievable minimal size of the deposited structures.Comment: 10 pages including 11 figures in Revte

Singular value decomposition in parametrised tests of post-Newtonian theory

Various coefficients of the 3.5 post-Newtonian (PN) phasing formula of non-spinning compact binaries moving in circular orbits is fully characterized by the two component masses. If two of these coefficients are independently measured, the masses can be estimated. Future gravitational wave observations could measure many of the 8 independent PN coefficients calculated to date. These additional measurements can be used to test the PN predictions of the underlying theory of gravity. Since all of these parameters are functions of the two component masses, there is strong correlation between the parameters when treated independently. Using Singular Value Decomposition of the Fisher information matrix, we remove this correlations and obtain a new set of parameters which are linear combinations of the original phasing coefficients. We show that the new set of parameters can be estimated with significantly improved accuracies which has implications for the ongoing efforts to implement parametrised tests of PN theory in the data analysis pipelines.Comment: 17 pages, 6 figures, Accepted for publication in Classical and Quantum Gravity (Matches with the published version

Glycated haemoglobin versus oral glucose tolerance test in screening for gestational diabetes mellitus

Background: Glycated haemoglobin (HbA1c) has been documented as an easier, useful tool in diagnosis of diabetes and can be considered as a screening tool in GDM as compared to oral glucose tolerance test (OGTT) which has practical constraints like long waiting period in fasting, too many pricks and non-compliance to glucose load solution. The objective of the study was to find out the utility of HbA1c as a diagnostic tool when compared with OGTT in screening of GDM.Methods: A retrospective study was conducted at Sri Venketeswaraa Medical College, Hospital and Research Center, Puducherry including 500 antenatal women attending to the Department of Obstetrics and Gynaecology for their ante-natal checkup during the period from August 2016 to April 2018. HbA1c levels were estimated and ROC curve analysis was done to estimate sensitivity and specificity against gold standard OGTT.Results: The HbA1c levels among the study subjects varied from 4.3% to 8.2%. The mean HbA1c levels among those diagnosed as GDM by gold standard OGTT was 5.82±1.1% and among those without GDM was 5.13±0.7%. The area under the ROC curve was 0.773 (95% CI 0.732–0.814). An HbA1c cut-off value of ≥5.91% had sensitivity of 34.6% and Specificity of 98.2% in diagnosing GDM. An HbA1c cut-off value of ≥5.32% had sensitivity of 84.8% and specificity of 60.1% in diagnosing GDM.Conclusions: HbA1c levels cannot substitute OGTT in diagnosis of GDM. A higher specific cut-off HbA1c value of ≥5.95% is diagnostic of GDM

Purification of Mixed State with Closed Timelike Curve is not Possible

In ordinary quantum theory any mixed state can be purified in an enlarged Hilbert space by bringing an ancillary system. The purified state does not depend on the state of any extraneous system with which the mixed state is going to interact and on the physical interaction. Here, we prove that it is not possible to purify a mixed state that traverses a closed time like curve (CTC) and allowed to interact in a consistent way with a causality-respecting (CR) quantum system in the same manner. Thus, in general for arbitrary interactions between CR and CTC systems there is no universal 'Church of the larger Hilbert space' for mixed states with CTC. This shows that in quantum theory with CTCs there can exist 'proper' and 'improper' mixtures.Comment: Latex2e, No Figs, 4 + pages, An error corrected, Results unchange

Transition to zero resistance in a two dimensional electron gas driven with microwaves

High-mobility 2D electron systems in a perpendicular magnetic field exhibit zero resistance states (ZRS) when driven with microwave radiation. We study the nonequilibrium phase transition into this ZRS using phenomenological equations of motion to describe the current and density fluctuations. We focus on two models for the transition into a time-independent steady state. Model-I assumes rotational invariance, density conservation, and symmetry under shifting the density globally by a constant. This model is argued to describe physics on small length scales where the density does not vary appreciably from its mean. The ordered state that arises in this case breaks rotational invariance and consists of a uniform current and transverse Hall field. We discuss some properties of this state, such as stability to fluctuations and the appearance of a Goldstone mode associated with the continuous symmetry breaking. Using dynamical renormalization group techniques, we find that with short-range interactions this model can admit a continuous transition described by mean-field theory, whereas with long-range interactions the transition is driven first-order. Model-II, which assumes only rotational invariance and density conservation and is argued to be appropriate on longer length scales, is shown to predict a first-order transition with either short- or long-range interactions. We discuss implications for experiments, including scaling relations and a possible way to detect the Goldstone mode in the case of a continuous transition into the ZRS, as well as possible signatures of a first-order transition in larger samples. We also point out the connection of our work to the well-studied phenomenon of `flocking'.Comment: 13 pages, 2 fig

Contribución al estudio del "Pilling".

Los hilos una vez confeccionados en tejidos -de calada y de punto- presentan distintas aptitudes a la formación de «pilling». Una serie de ensayos nos permite establecer un sistema sencillo y práctico de determinar dicha aptitud. Fotográficamente se demuestra la formación del fenómeno de «pilling» y a través de un análisis microscópico de la bolita de «pilling» se estudia su composición y la forma de rotura de las fibras. Se desarrolla un método de valoración del «pilling» en función del peso de las bolitas producidas, estableciendo una correlación entre las normas existentes para la valoración del «pilling» y el peso de las bolitas desarrolladas.Yarns once converted in a fabric -woven or knitted- presenlt different aptitude to the formation of pilling. Through a series of tests we can establish a simple and practical system for determining the said aptitude. The phenomenon of the formation of pilling is demonstrated through photographs and its composition and the way the fibres break is studied by microscopical analysis. A new method of evaluating pilling as a function of the weight of the pilling produced, is developed and a possible correlation between the existing standards for pilling and this method is established.Les fils qui ont été confectionnés en tissus et tricots présentent différentes aptitudes au boulochage. Une série d'essais nous permet d'établir un systeme simple et pratique pour la détermination de cette aptitude. On démontre plhotographiquement la formation du phenomhne du «pilling» et moyennant une analyse microscopique de la bouloche du «pilling» on étudie sa composition ainsi que la forme de la rupture des fibres. On développe une méthode d'évaluation du «pilling» en fonction du poids des bouloches produites et on établit une correlation entre les normes existantes poul l'évaluation du «pilling» et le poids des bouloches développées.Peer Reviewe