Evolution of Quantum Discord and its Stability in Two-Qubit NMR Systems

We investigate evolution of quantum correlations in ensembles of two-qubit nuclear spin systems via nuclear magnetic resonance techniques. We use discord as a measure of quantum correlations and the Werner state as an explicit example. We first introduce different ways of measuring discord and geometric discord in two-qubit systems and then describe the following experimental studies: (a) We quantitatively measure discord for Werner-like states prepared using an entangling pulse sequence. An initial thermal state with zero discord is gradually and periodically transformed into a mixed state with maximum discord. The experimental and simulated behavior of rise and fall of discord agree fairly well. (b) We examine the efficiency of dynamical decoupling sequences in preserving quantum correlations. In our experimental setup, the dynamical decoupling sequences preserved the traceless parts of the density matrices at high fidelity. But they could not maintain the purity of the quantum states and so were unable to keep the discord from decaying. (c) We observe the evolution of discord for a singlet-triplet mixed state during a radio-frequency spin-lock. A simple relaxation model describes the evolution of discord, and the accompanying evolution of fidelity of the long-lived singlet state, reasonably well.Comment: 9 pages, 7 figures, Phys. Rev. A (in press

A COMPARATIVE CLINICAL STUDY TO ASSESS THE EFFICACY OF KARIMBIRUMBADI KASHAYAM AND VASAGULUCHYADI KASHAYAM IN PANDUROGA WITH SPECIAL REFERENCE TO IRON DEFICIENCY ANEMIA IN THE REPRODUCTIVE AGE GROUP OF WOMEN

This study is an attempt to clinically analyze the independent effect of Karimbirumbadi kashayam and Vasaguluchiadi kashayam in Panduroga and also compare their efficacy. Aims and Objectives: To evaluate the comparative efficacy of Karimbirumbadi kashayam and Vasaguluchyadi kashayam in Panduroga with special reference to iron deficiency anemia in the reproductive age group of women. Methodology: Among 46 registered subjects, 22 were registered in group A and 24were registered in group B. Out of which 20 subjects of A group and 20 subjects of B group completed the study. Group A was administered with 25ml of Karimbirumbadi kashayam with 40ml of luke warm water twice daily before food for 2 months and Group B was administered with 25ml of Vasaguluchyadi kashayam with 40ml of luke warm water and 10ml of Madhu as Anupana twice daily before food for 2 months. Objective and subjective parameters were analyzed using paired T test and Wilcoxon signed rank test respectively. Independent T test and Mann-Whitney U test were used to compare the parameters between the groups. Result: There was statistically significant improvement in the objective and subjective parameters (p<0.05 was observed). Conclusion: The study shows that both Karimbirumbadi kashayam and Vasaguluchyadi kashayam are effective in relieving the symptoms of Panduroga. Symptomatic relief was seen in both the group A & B, but there was no statistically significant difference between the groups in relieving these symptoms

Storing entanglement of nuclear spins via Uhrig Dynamical Decoupling

Stroboscopic spin flips have already been shown to prolong the coherence times of quantum systems under noisy environments. Uhrig's dynamical decoupling scheme provides an optimal sequence for a quantum system interacting with a dephasing bath. Several experimental demonstrations have already verified the efficiency of such dynamical decoupling schemes in preserving single qubit coherences. In this work we describe the experimental study of Uhrig's dynamical decoupling in preserving two-qubit entangled states using an ensemble of spin-1/2 nuclear pairs in solution state. We find that the performance of odd-order Uhrig sequences in preserving entanglement is superior to both even-order Uhrig sequences and periodic spin-flip sequences. We also find that there exists an optimal length of the Uhrig sequence at which the decoherence time gets boosted from a few seconds to about 30 seconds.Comment: 6 pages, 7 figure

A stem-cell-derived platform enables complete Cryptosporidium development in vitro and genetic tractability

Despite being a frequent cause of severe diarrheal disease in infants and an opportunistic infection in immunocompromised patients, Cryptosporidium research has lagged due to a lack of facile experimental methods. Here, we describe a platform for complete life cycle development and long-term growth of C. parvum in vitro using air-liquid interface (ALI) cultures derived from intestinal epithelial stem cells. Transcriptomic profiling revealed that differentiating epithelial cells grown under ALI conditions undergo profound changes in metabolism and development that enable completion of the parasite life cycle in vitro. ALI cultures support parasite expansion \u3e 100-fold and generate viable oocysts that are transmissible in vitro and to mice, causing infection and animal death. Transgenic parasite lines created using CRISPR/Cas9 were used to complete a genetic cross in vitro, demonstrating Mendelian segregation of chromosomes during meiosis. ALI culture provides an accessible model that will enable innovative studies into Cryptosporidium biology and host interactions

Nonexponetial relaxation of photoinduced conductance in organic field effect transistor

We report detailed studies of the slow relaxation of the photoinduced excess charge carriers in organic metal-insulator-semiconductor field effect transistors consisting of poly(3-hexylthiophene) as the active layer. The relaxation process cannot be physically explained by processes, which lead to a simple or a stretched-exponential decay behavior. Models based on serial relaxation dynamics due to a hierarchy of systems with increasing spatial separation of the photo-generated negative and positive charges are used to explain the results. In order to explain the observed trend, the model is further modified by introducing a gate voltage dependent coulombic distribution manifested by the trapped negative charge carriers.Comment: 17 pages, 3 Figure

The influence of stigma on HIV risk behavior among men who have sex with men in Chennai, India

Stigma has been shown to increase vulnerability to HIV acquisition in many settings around the world. However, limited research has been conducted examining its role among men who have sex with men (MSM) in India, whose HIV prevalence is far greater than the general population. In 2009, 210 MSM in Chennai completed an interviewer-administered assessment, including questions about stigma, sexual-risk, demographics, and psychosocial variables. More than one fifth of the MSM reported unprotected anal sex (UAS) in the past three months. Logistic regression procedures were used to examine correlates of having experienced stigma. The 11-item stigma scale had high internal consistency reliability (Cronbach's alpha=0.99). Almost 2/5ths (39%) reported a high-level of experienced stigma (≥12 mean scale-score) in their lifetime, and the mean stigma scale score was 12 (SD=2.0). Significant correlates of having experienced prior stigma, after adjusting for age and educational attainment, included: identifying as a kothi (feminine acting/appearing and predominantly receptive in anal sex) compared to a panthi (masculine appearing, predominantly insertive) (AOR= 63.23; 95% CI: 15.92, 251.14; p<0.0001); being “out” about one's MSM behavior (AOR=5.63; 95% CI: 1.46, 21.73; p=0.01); having clinically significant depressive symptoms (AOR=2.68; 95% CI: 1.40, 5.12; p=0.003); and engaging in sex work in the prior 3 months (AOR=4.89; 95% CI: 2.51, 9.51; p<0.0001). These findings underscore the need to address psychosocial issues of Indian MSM. Unless issues such as stigma are addressed, effective HIV prevention interventions for this hidden population remain a challenge

Search for gravitational waves from low mass compact binary coalescence in LIGO’s sixth science run and Virgo’s science runs 2 and 3

We report on a search for gravitational waves from coalescing compact binaries using LIGO and Virgo observations between July 7, 2009, and October 20, 2010. We searched for signals from binaries with total mass between 2 and 25M⊙; this includes binary neutron stars, binary black holes, and binaries consisting of a black hole and neutron star. The detectors were sensitive to systems up to 40 Mpc distant for binary neutron stars, and further for higher mass systems. No gravitational-wave signals were detected. We report upper limits on the rate of compact binary coalescence as a function of total mass, including the results from previous LIGO and Virgo observations. The cumulative 90% confidence rate upper limits of the binary coalescence of binary neutron star, neutron star-black hole, and binary black hole systems are 1.3×10−4, 3.1×10−5, and 6.4×10−6  Mpc−3 yr−1, respectively. These upper limits are up to a factor 1.4 lower than previously derived limits. We also report on results from a blind injection challenge

Medium modification of jet fragmentation in Au+Au collisions at sqrt(s_NN)=200 GeV measured in direct photon-hadron correlations

The jet fragmentation function is measured with direct photon-hadron correlations in p+p and Au+Au collisions at sqrt(s_NN)=200 GeV. The p_T of the photon is an excellent approximation to the initial p_T of the jet and the ratio z_T=p_T^h/p_T^\gamma is used as a proxy for the jet fragmentation function. A statistical subtraction is used to extract the direct photon-hadron yields in Au+Au collisions while a photon isolation cut is applied in p+p. I_ AA, the ratio of jet fragment yield in Au+Au to that in p+p, indicates modification of the jet fragmentation function. Suppression, most likely due to energy loss in the medium, is seen at high z_T. The fragment yield at low z_T is enhanced at large angles. Such a trend is expected from redistribution of the lost energy into increased production of low-momentum particles.Comment: 562 authors, 70 insitutions, 8 pages, and 3 figures. Submitted to Phys. Rev. Lett. v2 has minor changes to improve clarity. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

Nuclear matter effects on J/ψJ/\psi production in asymmetric Cu+Au collisions at sNN\sqrt{s_{_{NN}}} = 200 GeV

We report on $J/\psi$ production from asymmetric Cu+Au heavy-ion collisions at $\sqrt{s_{_{NN}}}$=200 GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of $J/\psi$ yields in Cu$+$Au collisions in the Au-going direction is found to be comparable to that in Au$+$Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, $J/\psi$ production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-$x$ gluon suppression in the larger Au nucleus. The relative suppression is opposite to that expected from hot nuclear matter dissociation, since a higher energy density is expected in the Au-going direction.Comment: 349 authors, 10 pages, 4 figures, and 4 tables. Submitted to Phys. Rev. C. For v2, fixed LaTeX error in 3rd-to-last sentence. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

J/psi suppression at forward rapidity in Au+Au collisions at sqrt(s_NN)=39 and 62.4 GeV

We present measurements of the J/psi invariant yields in sqrt(s_NN)=39 and 62.4 GeV Au+Au collisions at forward rapidity (1.2<|y|<2.2). Invariant yields are presented as a function of both collision centrality and transverse momentum. Nuclear modifications are obtained for central relative to peripheral Au+Au collisions (R_CP) and for various centrality selections in Au+Au relative to scaled p+p cross sections obtained from other measurements (R_AA). The observed suppression patterns at 39 and 62.4 GeV are quite similar to those previously measured at 200 GeV. This similar suppression presents a challenge to theoretical models that contain various competing mechanisms with different energy dependencies, some of which cause suppression and others enhancement.Comment: 365 authors, 10 pages, 11 figures, 4 tables. Submitted to Phys. Rev. C. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm