Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Coherent preparation by laser light of quantum states of atoms and molecules can lead to quantum interference in the amplitudes of optical transitions. In this way the optical properties of a medium can be dramatically modified, leading to electromagnetically induced transparency and related effects, which have placed gas-phase systems at the center of recent advances in the development of media with radically new optical properties. This article reviews these advances and the new possibilities they offer for nonlinear optics and quantum information science. As a basis for the theory of electromagnetically induced transparency the authors consider the atomic dynamics and the optical response of the medium to a continuous-wave laser. They then discuss pulse propagation and the adiabatic evolution of field-coupled states and show how coherently prepared media can be used to improve frequency conversion in nonlinear optical mixing experiments. The extension of these concepts to very weak optical fields in the few-photon limit is then examined. The review concludes with a discussion of future prospects and potential new applications.

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Electromagnetically induced transparency : Optics in coherent media

as quantum engineering. In the past two decades it has become increasingly clear that many (perhaps all) of the symptoms of classicality can be induced in quantum systems by their environments. Thus decoherence is caused by the interaction in which the environment in effect monitors certain observables of the system, destroying coherence between the pointer states corresponding to their eigenvalues. This leads to environment-induced superselection or einselection, a quantum process associated with selective loss of information. Einselected pointer states are stable. They can retain correlations with the rest of the universe in spite of the environment. Einselection enforces classicality by imposing an effective ban on the vast majority of the Hilbert space, eliminating especially the flagrantly nonlocal ''Schrodinger-cat states.'' The classical structure of phase space emerges from the quantum Hilbert space in the appropriate macroscopic limit. Combination of einselection with dynamics leads to the idealizations of a point and of a classical trajectory. In measurements, einselection replaces quantum entanglement between the apparatus and the measured system with the classical correlation. Only the preferred pointer observable of the apparatus can store information that has predictive power. When the measured quantum system is microscopic and isolated, this restriction on the predictive utility of its correlations with the macroscopic apparatus results in the effective ''collapse of the wave packet.'' The existential interpretation implied by einselection regards observers as open quantum systems, distinguished only by their ability to acquire, store, and process information. Spreading of the correlations with the effectively classical pointer states throughout the environment allows one to understand ''classical reality'' as a property based on the relatively objective existence of the einselected states. Effectively classical pointer states can be ''found out'' without being re-prepared, e.g, by intercepting the information already present in the environment. The redundancy of the records of pointer states in the environment (which can be thought of as their ''fitness'' in the Darwinian sense) is a measure of their classicality. A new symmetry appears in this setting. Environment-assisted invariance or envariance sheds new light on the nature of ignorance of the state of the system due to quantum correlations with the environment and leads to Born's rules and to reduced density matrices, ultimately justifying basic principles of the program of decoherence and einselection.

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Decoherence, einselection, and the quantum origins of the classical

Microcavity physics and design will be reviewed. Following an overview of applications in quantum optics, communications and biosensing, recent advances in ultra-high-Q research will be presented.

Optical microcavities

The science of quantum information has arisen over the last two decades centered on the manipulation of individual quanta of information, known as quantum bits or qubits. Quantum computers, quantum cryptography, and quantum teleportation are among the most celebrated ideas that have emerged from this new field. It was realized later on that using continuous-variable quantum information carriers, instead of qubits, constitutes an extremely powerful alternative approach to quantum information processing. This review focuses on continuous-variable quantum information processes that rely on any combination of Gaussian states, Gaussian operations, and Gaussian measurements. Interestingly, such a restriction to the Gaussian realm comes with various benefits, since on the theoretical side, simple analytical tools are available and, on the experimental side, optical components effecting Gaussian processes are readily available in the laboratory. Yet, Gaussian quantum information processing opens the way to a wide variety of tasks and applications, including quantum communication, quantum cryptography, quantum computation, quantum teleportation, and quantum state and channel discrimination. This review reports on the state of the art in this field, ranging from the basic theoretical tools and landmark experimental realizations to the most recent successful developments.

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Gaussian quantum information

Weitere Fachgebiete > Physik, Astronomie > Elektrodynakmik, Optik > Optik Zu Leseprobe schnell und portofrei erhältlich bei

Summary form only given. The observation of atomic Bose-Einstein condensates (BECs) in magnetic and optical traps has stimulated theoretical investigation of the optical properties of these systems. Many of the current theories are based on the Heisenberg equations of motion for the radiation field and matter. These equations are nonlinear in the field operators and lead to an infinite hierarchy of equations for the atomic correlation functions. The hierarchy can be decoupled using an approximation. In an alternative development, the Heisenberg equations of motion have been simplified using an adiabatic approximation to eliminate the excited-state field operator. While some previous studies of BECs have employed the polariton approach, in these treatments neither the local field effects nor the polariton-phonon coupling are taken into account. Local field effects play an important role in a dense Bose gas (/spl rho//sup I/3//spl lambda//spl Lt/1) where, due to the resonance dipole-dipole interaction,the atoms respond to the electromagnetic field in a collective manner.In this contribution we examine the effects of both the local field and phonons using the polariton approach. The analysis is based on the quasiparticle concept.

Effects due to the local fields and the phonons in atomic Bose-Einstein condensates: polariton approach

We study collective spontaneous emission from arbitrary distributions of N two-state atoms using quantum trajectory theory and without an a priori single-mode assumption. Assuming a fully excited initial state, we calculate the angular distribution of the average integrated intensity. We investigate the dependence of the angular distribution of emission on the geometry of the atomic distribution. The formalism is developed around an unravelling of the master equation in terms of source mode quantum jumps. A modified boson approximation is made to treat the many-atom case, where it is found that strong directional superradiance occurs for a few hundred to a few thousand atoms. In order to illustrate important differences between our model and single-mode models we consider shot-to-shot intensity fluctuations and angular correlations in the emitted intensity.

Collective spontaneous emission from small assemblies of atoms

The resonant heating of a harmonically trapped ion by a standing-wave light field is described as a quantum stochastic process combining a coherent Schroedinger evolution with Bohr-Einstein quantum jumps. The dependence of the center-of-mass motion on Lamb-Dicke parameter is studied. For Lamb-Dicke parameters greater than unity we demonstrate significant departures from the diffusion process that holds in the limit of small momentum

Quantum Stochastic Heating of a Trapped Ion through Resonance Fluorescence

It has been an important development in optical bistability to learn that bistable systems may become unstable, and for a cw input produce an oscillating output, either periodic or chaotic. Instabilities leading to periodic self-oscillation were first discussed by McCall1 and Bonifacio and Lugiato.2 The rapid growth of interest in optical chaos has followed Ikeda’s prediction of chaotic oscillations in a ring cavity with a dispersive nonlinearity.3 Experimental investigations of Ikeda’s proposal have been made4,5 and further predictions of chaos in bistable and multistable systems have been reported.6–10

Howard J. Carmichael

Papers

Weitere Fachgebiete > Physik, Astronomie > Elektrodynakmik, Optik > Optik Zu Leseprobe schnell und portofrei erhältlich bei

Effects due to the local fields and the phonons in atomic Bose-Einstein condensates: polariton approach

Collective spontaneous emission from small assemblies of atoms

Quantum Stochastic Heating of a Trapped Ion through Resonance Fluorescence

Multistability, self-oscillation and chaos in nonlinear optics