Search results for "Models"
showing 10 items of 8211 documents
Monoamine Oxidase Inhibition by β-Carbolines: A Quantum Chemical Approach
1979
Monoamine oxidase inhibition by beta-carboline derivatives is related to the energy change, delta E, arising from complex formation between the inhibitor and the enzyme. The energy change was expressed in terms of electronic indexes, which were estimated for a set of aromatic beta-carbolines. The electronic indexes were correlated to the experimental activity indexes by a simplified quantum chemical perturbational treatment with a multiple regression procedure. A characteristic structure for the inhibitor-enzyme complex was derived from the correlation. The molecules are linked by two kinds of bond. One involves the lone pyridine nitrogen pair of beta-carbolines; the other is due to a pi-el…
Vanishing chiral couplings in the large-Nc resonance theory
2007
5 pages, 2 figures.-- PACS nrs.: 12.39.Fe; 11.15.Pg; 12.38.-t.-- ISI Article Identifier: 000247625300022.-- ArXiv pre-print available at: http://arxiv.org/abs/hep-ph/0611375
Pion transverse momentum dependent parton distributions in the Nambu and Jona-Lasinio model
2015
An explicit evaluation of the two pion transverse momentum dependent parton distributions at leading twist is presented, in the framework of the Nambu-Jona Lasinio model with Pauli-Villars regularization. The transverse momentum dependence of the obtained distributions is generated solely by the dynamics of the model. Using these results, the so called generalized Boer-Mulders shift is studied and compared with recent lattice data. The obtained agreement is very encouraging, in particular because no additional parameter has been introduced. A more conclusive comparison would require a precise knowledge of the QCD evolution of the transverse momentum dependent parton distributions under scru…
Objective features in quantum states
2023
One of the key features of quantum mechanics is that any superposition of quantum states is in itself a legitimate quantum state. This has far reaching consequences, and is behind the stark difference in behaviour between quantum and classical systems. In particular, quantum systems are not -unlike classical ones- intrinsically objective, that is, different observers are not always able to agree on the properties of the system. Understanding the conditions for objectivity in quantum states is therefore key to address the wider issue of the quantum-to-classical transition. Here, we discuss several aspects of quantum objectivity, and in particular subtleties that arise to the definitions of o…
Phase transition of light on complex quantum networks
2012
Recent advances in quantum optics and atomic physics allow for an unprecedented level of control over light-matter interactions, which can be exploited to investigate new physical phenomena. In this work we are interested in the role played by the topology of quantum networks describing coupled optical cavities and local atomic degrees of freedom. In particular, using a mean-field approximation, we study the phase diagram of the Jaynes-Cummings-Hubbard model on complex networks topologies, and we characterize the transition between a Mott-like phase of localized polaritons and a superfluid phase. We found that, for complex topologies, the phase diagram is non-trivial and well defined in the…
Collision models in quantum optics
2017
AbstractQuantum collision models (CMs) provide advantageous case studies for investigating major issues in open quantum systems theory, and especially quantum non-Markovianity. After reviewing their general definition and distinctive features, we illustrate the emergence of a CM in a familiar quantum optics scenario. This task is carried out by highlighting the close connection between the well-known input-output formalism and CMs. Within this quantum optics framework, usual assumptions in the CMs’ literature - such as considering a bath of noninteracting yet initially correlated ancillas - have a clear physical origin.
Effective Theories for QCD-like at TeV Scale
2014
We study the Effective Field Theory of three QCD-like theories, which can be classified by having quarks in a complex, real or pseudo-real representations of the gauge group. The Lagrangians are written in a very similar way so that the calculations can be done using techniques from Chiral Perturbation Theory (ChPT). We calculated the vacuum-expectation-value, the mass and the decay constant of pseudo-Goldstone Bosons up to next-to-next-to leading order (NNLO) \cite{Bijnens:2009qm}. The various channels of general $n$ flavour meson-meson scattering of the three theories are systematically studied and calculated up to NNLO \cite{Bijnens:2011fm}. We also calculated the vector, axial-vector, s…
Faddeev study of heavy baryon spectroscopy
2007
16 pages, 3 figures.-- PACS nrs.: 12.39.Jh, 12.39.Pn, 14.20.-c.-- ISI Article Identifier: 000246249100015.-- ArXiv pre-print available at: http://arxiv.org/abs/hep-ph/0703257
Semileptonic bc to cc and bb to bc baryon decays and heavy quark spin symmetry
2009
5th International Conference on Quarks and Nuclear Physics (QNP09). Inst High Energy Phys Chinese Acad Sci, Beijing, PEOPLES R CHINA, SEP 21-25, 2009
Double parton distributions in the pion in the Nambu–Jona-Lasinio model
2019
Two-parton correlations in the pion, a non perturbative information encoded in double parton distribution functions, are investigated in the Nambu and Jona-Lasinio model. It is found that double parton distribution functions expose novel dynamical information on the structure of the pion, not accessible through one-body parton distributions, as it happens in several estimates for the proton target and in a previous evaluation for the pion, in a light-cone framework. Expressions and predictions are given for double parton distributions corresponding to leading-twist Dirac operators in the quark vertices, and to different regularization methods for the Nambu and Jona-Lasinio model. These resu…