Browsing School of Physics by Title
Now showing items 1575-1594 of 2105
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Quantum condensation from a tailored exciton population in a microcavity
(2009)An experiment is proposed on the coherent quantum dynamics of a semiconductor microcavity containing quantum dots. Modeling the experiment using a generalized Dicke model, we show that a tailored excitation pulse can ... -
Quantum conductance of a single magnetic atom: An ab initio study
(2010)Our ab initio study explains recent puzzling experiments on the conductance of a single Co adatom depos- ited either on Cu 111 or on ferromagnetic Co islands and contacted with both magnetic and nonmagnetic electrodes N. ... -
Quantum control of excitons for reversible heat transfer
(2019)Lasers, photovoltaics, and thermoelectrically-pumped light emitting diodes are thermodynamic machines which use excitons (electron-hole pairs) as the working medium. The heat transfers in such devices are highly irreversible, ... -
Quantum Control of Thermodynamic Processes in Semiconductors
(Trinity College Dublin. School of Physics. Discipline of Physics, 2022)In this thesis, we explore theoretically the thermodynamics of heat exchange in laser driven solid state systems. In particular, we focus on the heat exchanged between phonons and a semiconductor quantum dot exciton, driven ... -
Quantum corrections to the Ising interactions in LiYxHo1-xF4
(Springer, 2008)We systematically derive an effective Hamiltonian for the dipolar magnet LiY1?xHoxF4, including quantum corrections which arise from the transverse dipolar and hyperfine interactions. These corrections are derived using ... -
Quantum heat statistics with time-evolving matrix product operators
(2021)We present a numerically exact method to compute the full counting statistics of heat transfer in non-Markovian open quantum systems, which is based on the time-evolving matrix product operator algorithm. This approach is ... -
Quantum ratchets with few bands below the barrier
(American Physical Society, 2002)We investigate directed motion in nonadiabatically rocked ratchet systems sustaining few bands below the barrier. Upon restricting the dynamics to the lowest M bands, the total system-plus-bath Hamiltonian is mapped onto ... -
Quantum theory of multimode exciton-polariton Bose-Einstein Condensation
(Trinity College (Dublin, Ireland). School of Physics, 2013) -
Quantum theory of multimode polariton condensation
(2014)We develop a theory for the dynamics of the density matrix describing a multimode polariton condensate. In such a condensate several single-particle orbitals become highly occupied, due to stimulated scattering from reservoirs ... -
Quantum transport in 2D materials: Theoretical and computational optimisation of large heterostructures with spintronics properties
(Trinity College Dublin. School of Physics. Discipline of Physics, 2023)Graphene is a monolayer of carbon atoms arranged in a hexagonal lattice, making it the thinnest and strongest material known to man. Its exceptional electronic and thermal properties have generated great interest for its ... -
Quantum transport of Au-S-S-Au nanoscale junctions
(2012)Transport in S2 molecules sandwiched between Au electrodes is investigated with a combination of density functional theory and the non-equilibrium Green?s function method. We consider four different configurations and find ... -
Quantum work statistics and resource theories: Bridging the gap through Rényi divergences
(2019)The work performed on or extracted from a nonautonomous quantum system described by means of a two-point projective-measurement approach is a stochastic variable. We show that the cumulant generating function of work can ... -
Quasi-Periodic Pulsations in Solar Flares and the Earth's Ionosphere
(Trinity College Dublin. School of Physics. Discipline of Physics, 2019)Solar flares are the most powerful and energetic physical phenomena in our solar system, releasing radiation across the whole electromagnetic spectrum with total energies reaching on the order of 10^25 in a matter of ... -
Quasi-two-dimensional exciton in ZnSe/ZnMgSSe single quantum well
(American Physical Society, 1995)We have studied the quasi-two-dimensional exciton in ZnSe/ZnxMg1 ? xSySe1 ? y (x=0.85, y=0.21) single quantum wells (SQWs) by photoluminescence and photoluminescence excitation spectroscopy. Self-consistent calculations ... -
Quasiperiodic quantum heat engines with a mobility edge
(2020)Steady-state thermoelectric machines convert heat into work by driving a thermally generated charge current against a voltage gradient. In this work, we propose a new class of steady-state heat engines operating in the ... -
Radial oscillations of local density of states in carbon nanotubes
(2001)By performing an analytical study of the electronic structure of metallic carbon nanotubes, we show that the local density of states exhibits well-defined oscillations as a function of the nanotube radius. The periods ... -
Radiation-pressure-induced mode splitting in a spherical microcavity
(2007)In this work, we present a novel method to reveal azimuthal whispering gallery modes (WGMs) in a spherical microcavity coated with a nano-meter thick polyelectrolyte shell and one monolayer of CdTe semiconductor quantum ... -
Radio interferometric studies of cool evolved stellar winds
(Trinity College (Dublin, Ireland). School of Physics, 2013) -
Radioactivity from building materials in the Republic of Ireland
(Trinity College (Dublin, Ireland). School of Physics, 2006)This thesis presents the findings of a study undertaken to determine the radioactivity present in building materials in the Republic of Ireland. A total of 70 samples of commonly used building materials was collected from ... -
Raman scattering and Anti-Stokes emission from a single spherical microcavity with a CdTe quantum dot monolayer
(American Institute of Physics, 2003)We have studied the Raman and luminescence spectra of a microcavity?quantum dot system consisting of a melamine formaldehyde latex microsphere coated by CdTe colloidal quantum dots. The cavity-induced enhancement of the ...