Mixing and localisation in time-periodic quantum circuits

This thesis introduces and analyses a new model of time-periodic (Floquet) dynamics in a quantum spin systems. This model is implemented via a time-periodic quantum circuit with local Clifford gates. All the results of this thesis are rigorous mathematical proofs, which use tools and methods from quantum information science to study problems in many-body quantum systems and condensed-matter physics. This includes proofs of a form of dynamical mixing of Pauli operators in the case of local interactions, and conditions under which the evolution operator can resemble a random unitary. The scrambling time is of critical importance to these results, and in the case of non-local interactions, a slightly larger than logarithmic scrambling time is found. Also, the model analysed in this thesis has the peculiarity that it displays a strong form of localisation in one spatial dimension and the absence of localisation in two dimensions. There is no previously known model with these features, hence, this research is important to characterise the landscape of many-body quantum physics

Visualization of Geometric Spanner Algorithms

It is easier to understand an algorithm when it can be seen in interactive mode. The current study implemented four algorithms to construct geometric spanners; the path-greedy, gap-greedy, Theta-graph and Yao-graph algorithms. The data structure visualization framework (http://www.cs.usfca.edu/~galles/visualization/) developed by David Galles was used. Two features were added to allow its use in spanner algorithm visualization: support point-based algorithms and export of the output to Ipe drawing software format. The interactive animations in the framework make steps of visualization beautiful and media controls are available to manage the animations. Visualization does not require extensions to be installed on the web browser. It is available at http://cs.yazd.ac.ir/cgalg/AlgsVis/

The Effects of Implicit and Explicit Focus on Form on Oral Accuracy of EFL Learners

The current study was an attempt to reexamine the effectiveness of two kinds of form-focused instruction on oral accuracy of EFL learners. Participants of the current study were 41 male students in two experimental groups and a control group. During twelve sessions of treatment, to the first experimental group (class A), the target forms were taught implicitly through input enhancement (Implicit teaching). In the second class (class B), the grammatical structures were taught in explicit manner through metalinguistic explanation. However, to the control group (class C) no focus on form instruction was applied. A pre-test and a post-test were designed in interview model to test the oral accuracy of the learners both before and after treatment. In order to analyze the obtained scores from pre-test and post-test, paired sample T-Test was used to study the scores within each group, while one-way ANOVA was employed to study the mean variance between groups. The results showed that although both methods were beneficent, post-test scores of the students to whom the forms were taught explicitly were significantly higher than students to whom the forms were taught implicitly

Multiple Exciton Generation in Si and Ge Nanocrystals: An ab Initio Comparative Study

We have simulated multiexciton generation (MEG) processes in Si and Ge nanocrystals, employing the equation of motion coupled cluster single and double as a high-level ab initio approach. Simulations, consistent with the experimental results reported so far, reveal the key role of the d-polarized valence component in the chosen basis set on the accuracy and reliability of the results. Moreover, the MEG thresholds calculated with def2SVP basis set are ∼8.23(8.07) eV for seven (eight)-atom Si clusters and ∼7.58(6.84) eV for similar Ge clusters. The normalized MEG thresholds of Ge nanocrystals are 8% smaller with respect to Si. Thus, in contrast to Si, they are more appealing to the optical device designers for enhancing the device quantum efficiency. Furthermore, the resemblance of the symmetry of the simulated seven-atom clusters to those of the experimentally domelike grown nanocrystals makes the behavior of their MEG quantum probability similar

A Longitudinal Flap of Vena Cava in Live Donor a Safe Option for Adding Elongation at Least 10mm in Vein of Right Kidney

Introduction: To treat chronic kidney, kidney transplantation is the most efficient way especially when donor is alive, in such a way that survival tie can be increased in the best possible way. In this regard, major problem is short renal vein resulting in thrombosis. To elongate the vein length, there is a technique that we report in this study. Materials and Methods: The technique of interest is that at the time of dissection of vena cava and renal vein, it should be tried to put vein of vena cava 1cm above and 1cm below of renal vein. In addition, the kidney must be placed in right iliac of kidney done. Results: Patients discharged in good condition after two days. In our cases, there was no tension in the site of anastomosis showing safe condition. Conclusion: Longitudinal flap of vena cava accompanied by a suitable cuff can increase about I cm length of renal vein