Search results for "Quantum"
showing 10 items of 9714 documents
Does Creativity Help Us Survive? A Possible Approach with Quantum-Driven Robots
2022
How can we relate quantum computing, robotics, and music? This is a position paper where we try to connect these fields. We discuss one main question regarding computational creativity and we imagine an experimental setup to test our hypothesis. Artificial intelligence and autonomous machines can accomplish simple creative tasks such as reorganizing given material. Because creativity is a human (and not only) resource to survive, we wonder if also artificial agents, such as robots, might develop creativity at a higher level to ensure self-survival. Then, we design an experimental setup with three robots, playing and dancing. If music and movement flow is regular (with the beat difference be…
Síntesis y caracterización de compuestos de Cu(II) con derivados triazólicos. Estudio de su actividad como potenciales nucleasas químicas
2014
The main goal of this PhD thesis concerns the development of artificial metallonucleases based on copper(II)-1,2,4-triazole compounds. In order to do so, we have obtained metal compounds of different nuclearities by reaction of a new family of 1,2,4-triazole ligands with copper(II) salts. The ligands own the characteristic triazole properties upon coordinating to metals and also integrate DNA binding units (aromatic moieties) with the aim of increasing the affinity of the corresponding metal complexes to double strand DNA. We have also chosen the copper(II) ion due to its intrinsic redox and coordination properties. Here we present our conclusions in relation with their structure/activity a…
Strong field phenomena: Atoms, Molecules, Nanostructures.
Intrinsic spin-orbit interaction in diffusive normal wire Josephson weak links: Supercurrent and density of states
2016
We study the effect of the intrinsic (Rashba or Dresselhaus) spin-orbit interaction in superconductor–nanowire–superconductor (SNS) weak links in the presence of a spin-splitting field that can result either from an intrinsic exchange field or the Zeeman effect of an applied field. We solve the full nonlinear Usadel equations numerically [The code used for calculating the results in this paper is available in https://github.com/wompo/Usadel-for-nanowires] and analyze the resulting supercurrent through the weak link and the behavior of the density of states in the center of the wire. We point out how the presence of the spin-orbit interaction gives rise to a long-range spin triplet supercurr…
Optical Properties of III-V Nanowires and Their Application for Charge Transport and Single-Photon Emission
2012
This work covers the optical characterization of III-V semiconductor nanowires and their application for charge transport and for single-photon emission. InAs nanowires have been investigated by Raman scattering and PL spectroscopy. The possibility to grow nanowires with a crystal structure different from its bulk counterpart has aroused a lot of interest in their optical and electronic properties. Here, the optical phonon modes of wurtzite InAs nanowires have been studied by polarized Raman scattering. For the first time, Raman measurements on a single InAs nanowire have revealed the A1(TO) and E2h optical phonon modes of the wurtzite structure. Additional resonant Raman scattering experim…
Comparison of different theory models and basis sets in the calculation of 13C NMR chemical shifts of natural products.
2004
The influence of the calculation method in mimicking experimental 13C NMR chemical shifts of 15 low-polarity natural products singularly containing 10–20 carbon atoms was investigated by employing different quantum chemistry approaches and basis sets, both in the preliminary geometry optimizations and in the following single-point 13C GIAO calculations of the NMR chemical shifts. The geometries of the involved species were optimized at the PM3, HF, B3LYP and mPW1PW91 levels whereas the 13C NMR parameters were determined at the HF, B3LYP and mPW1PW91 levels. Different combinations of basis sets were also tested. The consistency and efficiency of the considered combinations of geometry optimi…
Four-Component Relativistic DFT Calculations of C-13 Chemical Shifts of Halogenated Natural Substances
2015
We have calculated the (13) C NMR chemical shifts of a large ensemble of halogenated organic molecules (81 molecules for a total of 250 experimental (13) C NMR data at four different levels of theory), ranging from small rigid organic compounds, used to benchmark the performance of various levels of theory, to natural substances of marine origin with conformational degrees of freedom. Carbon atoms bonded to heavy halogen atoms, particularly bromine and iodine, are known to be rather challenging when it comes to the prediction of their chemical shifts by quantum methods, due to relativistic effects. In this paper, we have applied the state-of-the-art four-component relativistic density funct…
Noise effect in a FitzHugh-Nagumo circuit driven by a bichromatic signal
2013
We analyze the response of a nonlinear circuit exactly ruled by the FitzHugh-Nagumo equations. This circuit is submitted to a bichromatic signal including a high frequency and a low frequency. In absence of noise, we show that for an appropriate amplitude of the high frequency driving, the response of the circuit estimated at the low frequency can be optimized via the phenomenon of vibrational resonance. Next, we show that under certain conditions, noise can contribute to the effect of vibrational resonance. Colored noise is also considered. Our experimental results are confirmed by a numerical analysis.
Coherence in neutrino oscillations
2011
The theory of neutrino oscillations has turned out to be the most reasonable explanation to the observed violations in lepton number conservation of solar and atmospheric neutrino fluxes. A derivation of the most important results of this theory is first given using a plane wave treatment and subsequently using a three-dimensional shape-independent wave packet approach. Both methods give the same oscillation patterns, but only the latter one serves as a decent starting point for analyzing coherence in neutrino oscillations. A numerical analysis of the oscillation patterns on various distance scales is also given to graphically illustrate the phenomenon of neutrino oscillation and loss of co…
Population Properties of Compact Objects from the Second LIGO-Virgo Gravitational-Wave Transient Catalog
2021
Abbott, R., et al. (LIGO and Virgo Collaboration)