The on-surface reactions of 10-bromo-10'-(2,6-dimethylphenyl)-9,9'-bianthracene on Au(111) surface have been investigated by a combination of bond-resolved scanning tunneling microscopy, scanning tunneling spectroscopy, and tightbinding and mean-field Hubbard calculations. The reactions afford the synthesis of two open-shell nanographenes (1a and 1b) exhibiting different scenarios of all-carbon magnetism. 1a, an allbenzenoid nanographene with previously unreported triangulenelike termini, contains a high proportion of zigzag edges, which endows it with an exceedingly low frontier gap of 110 meV and edge-localized states. The dominant reaction product (1b) is a non-benzenoid nanographene consisting of a single pentagonal ring in a benzenoid framework. The presence of this nonbenzenoid topological defect, which alters the bond connectivity in the hexagonal lattice, results in a non-Kekulé nanographene with a spin S = ½, which is detected as a Kondo resonance. Our work provides evidence of all-carbon magnetism, and motivates the use of topological defects as structural elements toward engineering agnetism in carbon-based nanomaterials for spintronics.

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In this work, we describe the synthesis and characterization of three novel sulfur-doped nanographenes (NGs) (1–3) containing multiple subhelicenes, including carbo[4]helicenes, thieno[4]helicenes, carbo[5]helicenes, and thieno[5]helicenes. Density functional theory calculations reveal that the helicene substructures in 1–3 possess dihedral angles from 15° to 34°. The optical energy gaps of 1–3 are estimated to be 2.67, 2.45, and 2.30 eV, respectively. These three sulfur-doped NGs show enlarged energy gaps compared to those of their pristine carbon analogues.

Deux expériences d'Optique Atomique Quantique sont étudiées dans ce manuscrit : l'expérience Hong-Ou-Mandel atomique ainsi qu'une expérience préliminaire au test des inégalités de Bell sur la variable d'impulsion de deux atomes. Ces deux expériences permettent de révéler des comportements très particuliers de la matière. La première produit une interférence à deux particules et la seconde suggère l'intrication de deux atomes en impulsion. Ces deux aspects de la mécanique quantique sont non-intuitifs et surprenants. Pouvoir les réaliser avec quelques atomes dans des environnements contrôlés est nécessaire à la consolidation de nos connaissances des lois de la nature et tout particulièrement quand mécanique quantique et gravitation sont à l'oeuvre simultanément. / We report two Quantum Atom Optics experiments : the atomic Hong-Ou-Mandel experiment and preliminary results toward Bell's inequality test on momentum of two atoms. Both experiments reveal interesting behaviors of matter. The first one shows a 2-particle interference and the second one suggests entanglement momenta between two atoms. These aspects of quantum mechanics are really surprising and unintuitive. Realizing these experiments with a few atoms in a controlled environment are necessary to strengthen our understanding of the world, particularly when quantum mechanics and gravitation act simultaneously.

This thesis deals with the following question: are there more eigenfunctions, other than the already known eigenfunctions, of the spin chain with elliptic interactions known as the Inozemtsev spin chain? The Inozemtsev spin chain interpolates between two quantum integrable spin chains, theHeisenberg spin chain and the Haldane-Shastry spin chain. Therefore it is interesting to explore eigenfunctions of the Inozemtsev spin chain in greater detail. Moreover, there exists connections between spin chains and their corresponding spinless continuum model, namely theCalogero-Sutherland models; a derivation of the connection between the Haldane-Shastry spin chain and the trigonometric interacting Calogero-Sutherland model is presented in this thesis. These connections state that the eigenfunctions of the Calogero-Sutherland model are also eigenfunctionsof the corresponding spin chain. An established connection between the Inozemtsev spin chain and the elliptic interacting Calogero-Sutherland model yields exact eigenfunctions with simple poles at coinciding arguments of the Inozemtsev spin chain. However, there are eigenfunctions of theelliptic Calogero-Sutherland model with second order zeros instead of simple poles at coinciding arguments. It is therefore interesting to see if a connection exists that relates the eigenfunctions of the elliptic Calogero-Sutherland model with second order zeros to eigenfunctionsof the Inozemtsev spin chain also with second order zeros. The main goal of this thesis is to explore eigenfunctions of the Inozemtsev spin chain with second order zeros for two magnons. This thesis uses analytical methods for finding these eigenfunctions and numerical methods have beenresorted to in the end. The numerical results indicate that the functions explored in this thesis fail to parametrise the eigenfunctions of the Inozemtsev spin chain, except for a few special cases. / Den här avhandlingen behandlar följande frågeställning: finns det fler egenfunktioner än de redan kända till spinnkedjan med elliptisk växelverkan känd som Inozemtsevs spinnkedja? Inozemtsevs spinnkedja interpolerar mellan Heisenbergs spinnkedja och Haldane-Shastrys spinnkedja som båda ärkvant-integrerbara. Därför är det intressant att vidare utforska egenfunktionerna hos Inozemtsevs spinnkedja. Det finns kopplingar mellan spinnkedjor och spinnfria en-dimensionella kontinuumsystem, nämligen Calogero-Sutherlands system; en sådan koppling mellan Haldane-Shastrysspinnkedja och Calogero-Sutherlands modell med trigonometrisk växelverkan härleds i denna avhandling. Dessa kopplingar konstaterar att egenfunktionerna för Calogero-Sutherland systemet är egenfunktioner för spinnkedjan också. En koppling existerar mellan Calogero-Sutherland modellen med elliptisk växelverkan och Inozemtsevs spinnkedja vilket ger exakta egenfunktioner hos Inozemtsevs modell med enkla poler vid sammanfallande argument. Däremot existerar det egenfunktioner till Calogero-Sutherland modellen med elliptisk växelverkan med andra ordningens nollor vid sammanfallande argument istället för enkla poler. Det är därför intressant att undersöka om det existerar en koppling mellan dessa två system med egenfunktioner med andra ordningens nollor; det här skulle då ge exakta egenfunktioner till Inozemtsevs spinnkedja med andra ordningens nollor. Detta är huvudsyftet med avhandlingen. Egenfunktioner med andra ordningens nollor för två magnoner undersöks. Avhandlingen använder sig av analytisk metod och har prövats med numeriska metoder. De numeriska resultaten indikerar att de undersökta funktionerna i denna avhandling misslyckas med att parametrisera egenfunktionerna till Inozemtsevs spinnkedja förutom vissa specifika fall.

<p>Optimization and Machine learning (ML) have emerged as two positively disruptive methodologies and have thus resulted in unprecedented applications in several domains of technology. In recent years, ML has forayed into physical sciences and provided promising outcomes thanks to its ability in representing and generalizing complex functions to reveal underlying relations among variables describing a system. By casting ML as an optimization task, we first focus on its application in solving quantum many-body problems. Leveraging the power of quantum computation, we develop hybrid quantum machine learning protocols and implement benchmark tests to calculate the band structures of two-dimensional materials. We also show how this method can be used to estimate the critical point for a quantum phase transition. One  hurdle in such techniques is related to parameter optimization, wherein to obtain the desired result, the parameters have to be optimized, which can be computationally intensive. For a particular class of problem and a choice of algorithm, we deduce a simple parameter setting rule. This rule is projected as a heuristic and is validated numerically for several problem instances. Finally, by venturing into thermal photonics, a framework that takes advantage of the spectral and spatial information of hyperspectral thermal images to establish a completely passive machine perception, titled HADAR is presented. A conventional deep neural network is developed that utilizes the governing equation of HADAR and its performance in semantic segmentation is demonstrated. Altogether, this report establishes the need for creative algorithms that exploit modern hardware to solve complex problems that were previously deemed unsolvable.</p>

<div>Field-orthogonal temporal mode analysis of optical fields was recently developed to form a new framework of quantum information science. But so far, the exact profiles of the temporal modes are not known, which makes it difficult to achieve mode selection and de-multiplexing. A novel feedback-iteration method which, combined with the stimulated emission method, can give rise to the exact forms of the temporal mode structure of pulse-pumped spontaneous parametric processes both for high gain parametric process, which gives rise to quantum entanglement in continuous variables, and for the low gain case, which produces a two-photon entangled state for discrete variables.</div><div><br></div><div>For the temporal mode analysis in high gain situations, the common treatment of parametric interaction Hamiltonian does not consider the issue of time ordering problem of interaction Hamiltonian and thus leads to the inaccurate conclusion that the mode structure and the temporal mode functions do not change as the gain increases. We use an approach that is usually employed for treating nonlinear interferometers and avoids the time ordering issue. This allows us to derive an evolution equation in differential-integral form. Numerical solutions for high gain situations indicate a gain-dependent mode structure that has its mode distributions changed and mode functions broadened as the gain increases. This will enable us to have a complete picture of the mode structure of parametric processes and produce high quality quantum sources for a variety of applications of quantum technology.</div><div><br></div><div>To verify the feedback-iteration method which measures temporal mode structure directly, we measure the joint spectral density of photon pairs produced with the spontaneous parametric down-conversion process of a pulse-pumped PPKTP crystal. The measurement method is based on a stimulated emission process which significantly improves the measurement time and accuracy compared with old spectrally resolved photon coincidence measurement. With the measured joint spectral density, the amplitude of the temporal modes can be obtained with the mathematical tool of singular value decomposition and compared with those measured directly with the feedback-iteration method.</div><div><br></div><div>Because the parametric amplifier is in essence a linear four-port device, it couples and linearly mixes two inputs before amplifying and sending them to two output ports. We show that for quadrature phase amplitudes, a parametric amplifier can replace beam splitters to play the role of mixer. We apply this idea to a continuous-variable quantum state teleportation scheme in which a parametric amplifier replaces a beam splitter in the Bell measurement. We show that this scheme is loss-tolerant in the Bell measurement process and thus demonstrate the advantage of parametric amplifiers over beam splitter in the applications in quantum measurement.</div>

In this work the structure of the electrochemical metal-liquid interface is determined through use of quantum mechanics, molecular simulation, and experiment. Herein are profiled the molecular dynamics details and results of solid-liquid interfaces at flat non-specific solid surfaces and copper metal electrodes. Ab initio quantum-mechanical calculations are reported and define the interatomic potentials in the simulations. Some of the quantum-mechanical calculations involve small copper clusters interacting with 3-mercaptopropanesulfonic acid (MPSA), sodium, chloride, bisulfate and cuprous ions. In connection with these I develop the electrode charge dynamics (ECD) routine to treat the charge mobility in a metal. ECD bridges the gap between small-scale metal-cluster ab initio calculations and large-scale simulations of metal surfaces of arbitrary geometry. As water is the most abundant surface species in aqueous systems, water determines much of the interfacial dynamics. In contrast to prior simulation work, simulations in this work show the presence of a dense 2D ice-like rhombus structure of water on the surface that is relatively impervious to perturbation by typical electrode charges. I also find that chloride ions are adsorbed at both positive and negative electrode potentials, in agreement with experimental findings. Including internal modes of vibration in the water model enhances the ion contact adsorption at the solid surface. In superconformal filling of copper chip interconnects, organic additives are used to bottom-up fill high-aspect ratio trenches or vias. I use molecular dynamics and rotating-disk-electrode experiments to provide insight into the function of MPSA, one such additive. It is concluded that the thiol head group of MPSA inhibits copper deposition by preferentially occupying the active surface sites. The sulfonate head group participates in binding the copper ions and facilitating their transfer to the surface. Chloride ions reduce the work function of the copper electrode, reduce the binding energy of MPSA to the copper surface, and attenuate the binding of copper ions to the sulfonate head group of MPSA.

In a strongly correlated material the localized electrons, typically the electrons in the 3d-orbitals, become entangled with each other through the Coulomb interaction. However, these electrons also interact with more mobile (itinerant) electrons in the s- and p-orbitals. The latter process called screening as it effectively reduces the strength of the interaction between the 3d-electrons. A less studied and often neglected effect of the screening is that it also entangles the 3d-electrons with the itinerant electrons, which is equivalent to a leakage of quantum information from the 3delectrons to the environment. This process leads to decoherence since it causes the 3d-electrons to effectively lose some of their quantum mechanical properties. But what does this mean for our understanding of strongly correlated materials and can this decoherence effect be of such magnitude that neglecting it may qualitatively affect the calculated material properties? This is the question this report tries to answer, but for a minimal impurity model consisting of an atom and a few surrounding bath orbitals. / I korrelerade atomer kan lokaliserade elektroner, som elektroner i 3d orbitaler, bli kvantmekaniskt sammanflätade med varandra genom coulomb-växelverkan. Dessa elektroner kan även växelverka med mer mobila elektroner, som elektroner i s- och p-orbitaler. Denna process kallas för skärmning eftersom den effektivt sätt reducerar styrkan på repulsionen mellan elektronerna i 3d-orbitalerna. En mindre känd och ofta ignorerad effekt från skärmningen är att elektronerna i 3d-orbitalerna blir kvantmekaniskt sammanflätade med de mobila elektronerna på ett irreversibelt sätt. Detta är ekvivalent med att information om d-elektronernas position läcker ut till omgivningen. Denna informationsläcka kallas för dekoherens eftersom den ledertill att d-elektronerna förlorar en del av sina kvantmekaniska egenskaper. Frågan blir således vad dekoherens kan ha för betydelse för starkt korrelerade materials egenskaper. Kan denna effekt vara av sådan magnitud att det ger oss en helt felaktig bild om den negligeras? Detta är vad denna rapport syftar till att svara på.

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