Floquet-engineered quantum state manipulation in a noisy qubit

Adiabatic evolution is a common strategy for manipulating quantum states and has been employed in diverse fields such as quantum simulation, computation and annealing. However, adiabatic evolution is inherently slow and therefore susceptible to decoherence. Existing methods for speeding up adiabatic evolution require complex many-body operators or are difficult to construct for multi-level systems. Using the tools of Floquet engineering, we design a scheme for high-fidelity quantum state manipulation, utilizing only the interactions available in the original Hamiltonian. We apply this approach to a qubit and experimentally demonstrate its performance with the electronic spin of a Nitrogen-vacancy center in diamond. Our Floquet-engineered protocol achieves state preparation fidelity of $0.994 \pm 0.004$, on the same level as the conventional fast-forward protocol, but is more robust to external noise acting on the qubit. Floquet engineering provides a powerful platform for high-fidelity quantum state manipulation in complex and noisy quantum systems

Effect of non-magnetic impurities on the magnetic states of anatase TiO2_2

The electronic and magnetic properties of TiO$_2$, TiO$_{1.75}$, TiO$_{1.75}$N$_{0.25}$, and TiO$_{1.75}$F$_{0.25}$ compounds have been studied by using \emph{ab initio} electronic structure calculations. TiO$_2$ is found to evolve from a wide-band-gap semiconductor to a narrow-band-gap semiconductor to a half-metallic state and finally to a metallic state with oxygen vacancy, N-doping and F-doping, respectively. Present work clearly shows the robust magnetic ground state for N- and F-doped TiO$_2$. The N-doping gives rise to magnetic moment of $\sim$0.4 $\mu_B$ at N-site and $\sim$0.1 $\mu_B$ each at two neighboring O-sites, whereas F-doping creates a magnetic moment of $\sim$0.3 $\mu_B$ at the nearest Ti atom. Here we also discuss the possible cause of the observed magnetic states in terms of the spatial electronic charge distribution of Ti, N and F atoms responsible for bond formation.Comment: 11 pages, 4 figures To appear J. Phys.: Condens. Matte

Enhanced photocatalytic degradation of diethyl phthalate using Zn doped rutile TiO2

A simple, room temperature sol gel synthesis approach has been made to obtain undoped and Zn doped TiO2 samples using titanium tetraisopropoxide and zinc acetate as precursors. The synthesized samples are predominantly in rutile phase which are rarely reported at the calcination temperature of 450 °C. The samples are characterized using X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Vis diffuse reflectance (DRS), thermo gravimetric analysis (TGA) and Raman spectroscopy. The as prepared samples have been used for the photocatalytic degradation of diethyl phthalate. Phthalate esters are one of the persistent organic pollutants found in the environment. Diethyl phthalate has been taken as a model pollutant. Zn doped TiO2 sample shows better photocatalytic activity as compared to undoped TiO2. The kinetic studies reveal that the photocatalytic degradation reaction follows a pseudo first order equation. The diethyl phthalate is almost completely degraded in about 200 min using 0.2 mol % Zn doped rutile TiO2

Towards the Formal Reliability Analysis of Oil and Gas Pipelines

It is customary to assess the reliability of underground oil and gas pipelines in the presence of excessive loading and corrosion effects to ensure a leak-free transport of hazardous materials. The main idea behind this reliability analysis is to model the given pipeline system as a Reliability Block Diagram (RBD) of segments such that the reliability of an individual pipeline segment can be represented by a random variable. Traditionally, computer simulation is used to perform this reliability analysis but it provides approximate results and requires an enormous amount of CPU time for attaining reasonable estimates. Due to its approximate nature, simulation is not very suitable for analyzing safety-critical systems like oil and gas pipelines, where even minor analysis flaws may result in catastrophic consequences. As an accurate alternative, we propose to use a higher-order-logic theorem prover (HOL) for the reliability analysis of pipelines. As a first step towards this idea, this paper provides a higher-order-logic formalization of reliability and the series RBD using the HOL theorem prover. For illustration, we present the formal analysis of a simple pipeline that can be modeled as a series RBD of segments with exponentially distributed failure times.Comment: 15 page

Determining the binding site of ORG27569 within the CB1 receptor

Computational studies to determine the binding site of ORG27569, a negative allosteric modulator, within the cannabinoid receptor 1 (CB1) reveal an intracellular binding domain as the most favorable binding site for ORG27569.https://egrove.olemiss.edu/pharm_facpost/1000/thumbnail.jp

Analysis of volume dependence of thermal expansivity for NaCl

In the present paper, a suitable model to evaluate the volume dependence of thermal expansivity α by using the reciprocal form of volume dependence of Anderson-Grüneisen parameter (δT) has been proposed. The newly developed relationship has satisfied the constraints of infinite pressure behavior, i.e., P → ∞ or V → 0. The results obtained through the present model show the consistency with the experimental data for NaCl