Design of Strongly Modulating Pulses to Implement Precise Effective Hamiltonians for Quantum Information Processing

We describe a method for improving coherent control through the use of detailed knowledge of the system's Hamiltonian. Precise unitary transformations were obtained by strongly modulating the system's dynamics to average out unwanted evolution. With the aid of numerical search methods, pulsed irradiation schemes are obtained that perform accurate, arbitrary, selective gates on multi-qubit systems. Compared to low power selective pulses, which cannot average out all unwanted evolution, these pulses are substantially shorter in time, thereby reducing the effects of relaxation. Liquid-state NMR techniques on homonuclear spin systems are used to demonstrate the accuracy of these gates both in simulation and experiment. Simulations of the coherent evolution of a 3-qubit system show that the control sequences faithfully implement the unitary operations, typically yielding gate fidelities on the order of 0.999 and, for some sequences, up to 0.9997. The experimentally determined density matrices resulting from the application of different control sequences on a 3-spin system have overlaps of up to 0.99 with the expected states, confirming the quality of the experimental implementation.Comment: RevTeX3, 11 pages including 2 tables and 5 figures; Journal of Chemical Physics, in pres

Electron-Impact Excitation from the (4p⁵5s) Metastable States of Krypton

Theoretical results from multistate semirelativistic Breit-Pauli R-matrix calculations and two first-order distorted-wave calculations are presented for electron-impact excitation of krypton from the (4p55s) J = 0,2 metastable states to the (4p55s) and (4p55p) manifolds. Except for a few cases, in which the method to account for relativistic effects becomes surprisingly critical, fair overall agreement between the predictions from the various theoretical models is achieved for intermediate and high energies. However, significant discrepancies remain with the few available experimental data

Personality Traits in Miners with Past Occupational Elemental Mercury Exposure

In this study, we evaluated the impact of long-term occupational exposure to elemental mercury vapor (Hg(0)) on the personality traits of ex-mercury miners. Study groups included 53 ex-miners previously exposed to Hg(0) and 53 age-matched controls. Miners and controls completed the self-reporting Eysenck Personality Questionnaire and the Emotional States Questionnaire. The relationship between the indices of past occupational exposure and the observed personality traits was evaluated using Pearson’s correlation coefficient and on a subgroup level by machine learning methods (regression trees). The ex-mercury miners were intermittently exposed to Hg(0) for a period of 7–31 years. The means of exposure-cycle urine mercury (U-Hg) concentrations ranged from 20 to 120 μg/L. The results obtained indicate that ex-miners tend to be more introverted and sincere, more depressive, more rigid in expressing their emotions and are likely to have more negative self-concepts than controls, but no correlations were found with the indices of past occupational exposure. Despite certain limitations, results obtained by the regression tree suggest that higher alcohol consumption per se and long-term intermittent, moderate exposure to Hg(0) (exposure cycle mean U-Hg concentrations > 38.7 < 53.5 μg/L) in interaction with alcohol remain a plausible explanation for the depression associated with negative self-concept found in subgroups of ex-mercury miners. This could be one of the reason for the higher risk of suicide among miners of the Idrija Mercury Mine in the last 45 years

Electron-Impact Excitation to the 4p⁵5s and 4p⁵5p Levels of Kr | Using Different Distorted-Wave and Close-Coupling Methods

Electron-impact excitation of the 4p55s and 4p55p levels of Kr I has been investigated in detail by calculating cross sections using distorted-wave and close-coupling approaches. The results are presented from the excitation thresholds up to 50 eV incident energy. They are contrasted among the different calculations and compared with other theoretical predictions and experimental data. Significant disagreement is found with many of the recent experimental data of Chilton et al. [Phys. Rev. A 62, 032714 (2000)]

Diffuse versus square-well confining potentials in modelling AA@C60_{60} atoms

Attention: this version-$2$ of the manuscript differs from its previously uploaded version-$1$ (arXiv:1112.6158v1) and subsequently published in 2012 J. Phys. B \textbf{45} 105102 only by a removed typo in Eq.(2) of version-$1$; there was the erroneous factor "2" in both terms in the right-hand-side of the Eq.(2) of version-$1$. Now that the typo is removed, Eq.(2) is correct. A perceived advantage for the replacement of a discontinuous square-well pseudo-potential, which is often used by various researchers as an approximation to the actual C$_{60}$ cage potential in calculations of endohedral atoms $A$@C$_{60}$, by a more realistic diffuse potential is explored. The photoionization of endohedral H@C$_{60}$ and Xe@C$_{60}$ is chosen as the case study. The diffuse potential is modelled by a combination of two Woods-Saxon potentials. It is demonstrated that photoionization spectra of $A$@C$_{60}$ atoms are largely insensitive to the degree $\eta$ of diffuseness of the potential borders, in a reasonably broad range of $\eta$'s. Alternatively, these spectra are found to be insensitive to discontinuity of the square-well potential either. Both potentials result in practically identical calculated spectra. New numerical values for the set of square-well parameters, which lead to a better agreement between experimental and theoretical data for $A$@C$_{60}$ spectra, are recommended for future studies.Comment: 11 pages, 4 figure

Student Evaluation of Faculty Physicians: Gender Differences in Teaching Evaluations

Purpose: To investigate whether there is a difference in medical student teaching evaluations for male and female clinical physician faculty. Methods: The authors examined all teaching evaluations completed by clinical students at one North American medical school in the surgery, obstetrics and gynecology, pediatrics, and internal medicine clinical rotations from 2008 to 2012. The authors focused on how students rated physician faculty on their ?overall quality of teaching? using a 5-point response scale (1?=?Poor to 5?=?Excellent). Linear mixed-effects models provided estimated mean differences in evaluation outcomes by faculty gender. Results: There were 14,107 teaching evaluations of 965 physician faculty. Of these evaluations, 7688 (54%) were for male physician faculty and 6419 (46%) were for female physician faculty. Female physicians received significantly lower mean evaluation scores in all four rotations. The discrepancy was largest in the surgery rotation (males?=?4.23, females?=?4.01, p?=?0.003). Pediatrics showed the next greatest difference (males?=?4.44, females?=?4.29, p?=?0.009), followed by obstetrics and gynecology (males?=?4.38, females?=?4.26, p?=?0.026), and internal medicine (males?=?4.35, females?=?4.27, p?=?0.043). Conclusions: Female physicians received lower teaching evaluations in all four core clinical rotations. This comprehensive examination adds to the medical literature by illuminating subtle differences in evaluations based on physician gender, and provides further evidence of disparities for women in academic medicine.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140140/1/jwh.2015.5475.pd