Search for: dipole-dipole-interactions
0.005 seconds

    Spin and charge fluctuations in a one-dimensional lattice with long-range interactions

    , Article Physica B: Condensed Matter ; Volume 571 , 2019 , Pages 204-209 ; 09214526 (ISSN) Talebi, A. H ; Davoudi, B ; Sharif University of Technology
    Elsevier B.V  2019
    We study the competition between spin and charge fluctuations of the extended Hubbard model with on-site and dipole-dipole interactions in a one-dimensional lattice. Using the extended two-particle self consistent (ETPSC) method, we find the corresponding expressions for spin and charge response functions. In this approach, the irreducible spin and charge vertices are a function of inter-particle distance (r) and wave-number (q). This theory allows us to determine the crossover temperatures and the dominant instability as a function of U and V. The phase diagrams are obtained for several effective particle densities: n = 0.5, n = 1 and n = 4/3. Each phase diagram (U − V − T space)... 

    Simulation of multipartite cavity quantum electrodynamics

    , Article IEEE Journal of Quantum Electronics ; Volume 49, Issue 12 , October , 2013 , Pages 1066-1079 ; 00189197 (ISSN) Alidoosty, M ; Khorasani, S. A ; Aram, M. H ; Sharif University of Technology
    Cavity quantum electrodynamics of multipartite systems are studied in depth, which consists of an arbitrary number of emitters in interaction with an arbitrary number of cavity modes. The governing model is obtained by taking the full field-dipole and dipole-dipole interactions into account, and is solved in the Schrödinger picture with assumption of vanishing field and dipole interactions at high energies. An extensive code is developed that is able to solve the system and track its evolution in time, while maintaining sufficient degrees of arbitrariness in setting up the initial conditions and interacting partitions. Using this code, we have been able to numerically evaluate various... 

    Theory and simulation of cavity quantum electro-dynamics in multi-partite quantum complex systems

    , Article Applied Physics A: Materials Science and Processing ; Vol. 115, issue. 2 , 2014 , p. 595-603 Alidoosty Shahraki, M ; Khorasani, S ; Aram, M. H ; Sharif University of Technology
    The cavity quantum electrodynamics of various complex systems is here analyzed using a general versatile code developed in this research. Such quantum multi-partite systems normally consist of an arbitrary number of quantum dots in interaction with an arbitrary number of cavity modes. As an example, a nine-partition system is simulated under different coupling regimes, consisting of eight emitters interacting with one cavity mode. Two-level emitters (e.g. quantum dots) are assumed to have an arrangement in the form of a linear chain, defining the mutual dipole-dipole interactions. It was observed that plotting the system trajectory in the phase space reveals a chaotic behavior in the... 

    Thermodynamic modeling of hydrogen sulfide solubility in ionic liquids using modified SAFT-VR and PC-SAFT equations of state

    , Article Fluid Phase Equilibria ; Volume 309, Issue 2 , 2011 , Pages 179-189 ; 03783812 (ISSN) Rahmati Rostami, M ; Behzadi, B ; Ghotbi, C ; Sharif University of Technology
    Equations of state based on the statistical associating fluid theory for potentials of variable range (SAFT-VR) and the perturbed chain statistical associating fluid theory (PC-SAFT) have been used to model the PVT behavior of ionic liquids and the solubility of H2S in six imidazolium-based ionic liquids. The studied systems included [bmim][PF6], [hmim][PF6], [bmim][BF4], [hmim][BF4], [bmim][NTF2] and [hmim][NTF2] at various temperatures and pressures.For pure components, parameters of the models have been obtained by fitting the models to experimental data on liquid densities; the average relative deviation between the calculated and experimental densities for ionic liquids is less than... 

    Mechanistic understanding of the interactions between nano-objects with different surface properties and α-synuclein

    , Article ACS Nano ; Volume 13, Issue 3 , 2019 , Pages 3243-3256 ; 19360851 (ISSN) Mohammad Beigi, H ; Hosseini, A ; Adeli, M ; Ejtehadi, M. R ; Christiansen, G ; Sahin, C ; Tu, Z ; Tavakol, M ; Dilmaghani Marand, A ; Nabipour, I ; Farzadfar, F ; Otzen, D. E ; Mahmoudi, M ; Hajipour, M. J ; Sharif University of Technology
    American Chemical Society  2019
    Aggregation of the natively unfolded protein α-synuclein (α-syn) is key to the development of Parkinson's disease (PD). Some nanoparticles (NPs) can inhibit this process and in turn be used for treatment of PD. Using simulation strategies, we show here that α-syn self-assembly is electrostatically driven. Dimerization by head-to-head monomer contact is triggered by dipole-dipole interactions and subsequently stabilized by van der Waals interactions and hydrogen bonds. Therefore, we hypothesized that charged nano-objects could interfere with this process and thus prevent α-syn fibrillation. In our simulations, positively and negatively charged graphene sheets or superparamagnetic iron oxide... 

    Interaction of quantum dot molecules with multi-mode radiation fields

    , Article Scientia Iranica ; Volume 17, Issue 1 D , 2010 , Pages 59-70 ; 10263098 (ISSN) Sadeghi, A. H ; Naqavi, A ; Khorasani, S ; Sharif University of Technology
    In this article, the interaction of an arbitrary number of quantum dots behaving as artificial molecules with different energy levels and a multi-mode electromagnetic field is studied. We make the assumption that each quantum dot can be represented as an atom with zero kinetic energy, and that all excitonic effects except dipole-dipole interactions may be. disregarded. We use the. Jaynes-Cummings-Paul model with applications to quantum systems based on a time-dependent Hamiltonian and entangled states. We obtain a system of equations describing the interaction, and present a method to solve the equations analytically for a single mode fi,eld within the Rotating-Wave Approximation. As an... 

    Role of precursors and coating polymers in sol-gel chemistry toward enhanced selectivity and efficiency in solid phase microextraction

    , Article Analytica Chimica Acta ; Volume 742 , 2012 , Pages 45-53 ; 00032670 (ISSN) Bagheri, H ; Piri Moghadam, H ; Ahdi, T ; Sharif University of Technology
    Elsevier  2012
    To evaluate the selectivity and efficiency of solid phase microextraction (SPME) fiber coatings, synthesized by sol-gel technology, roles of precursors and coating polymers were extensively investigated. An on-line combination of capillary microextraction (CME) technique and high performance liquid chromatography (HPLC) was set up to perform the investigation. Ten different fiber coatings were synthesized in which five of them contained only the precursor and the rests were prepared using both the precursor and coating polymer. All the coatings were chemically bonded to the inner surface of copper tubes, intended to be used as the CME device and already functionalized by self-assembly...