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

This paper reviews recent experimental and theoretical progress concerning many-body phenomena in dilute, ultracold gases. It focuses on effects beyond standard weak-coupling descriptions, such as the Mott-Hubbard transition in optical lattices, strongly interacting gases in one and two dimensions, or lowest-Landau-level physics in quasi-two-dimensional gases in fast rotation. Strong correlations in fermionic gases are discussed in optical lattices or near-Feshbach resonances in the BCS-BEC crossover.

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Many-Body Physics with Ultracold Gases

We extend earlier ideas about the appearance of noncommutative geometry in string theory with a nonzero B-field. We identify a limit in which the entire string dynamics is described by a minimally coupled (supersymmetric) gauge theory on a noncommutative space, and discuss the corrections away from this limit. Our analysis leads us to an equivalence between ordinary gauge fields and noncommutative gauge fields, which is realized by a change of variables that can be described explicitly. This change of variables is checked by comparing the ordinary Dirac-Born-Infeld theory with its noncommutative counterpart. We obtain a new perspective on noncommutative gauge theory on a torus, its T-duality, and Morita equivalence. We also discuss the D0/D4 system, the relation to M-theory in DLCQ, and a possible noncommutative version of the six-dimensional (2,0) theory.

https://iopscience.iop.org/article/10.1088/1126-6708/1999/09/032/pdf

String theory and noncommutative geometry

Topological quantum computation has emerged as one of the most exciting approaches to constructing a fault-tolerant quantum computer. The proposal relies on the existence of topological states of matter whose quasiparticle excitations are neither bosons nor fermions, but are particles known as non-Abelian anyons, meaning that they obey non-Abelian braiding statistics. Quantum information is stored in states with multiple quasiparticles, which have a topological degeneracy. The unitary gate operations that are necessary for quantum computation are carried out by braiding quasiparticles and then measuring the multiquasiparticle states. The fault tolerance of a topological quantum computer arises from the nonlocal encoding of the quasiparticle states, which makes them immune to errors caused by local perturbations. To date, the only such topological states thought to have been found in nature are fractional quantum Hall states, most prominently the $\ensuremath{\nu}=5∕2$ state, although several other prospective candidates have been proposed in systems as disparate as ultracold atoms in optical lattices and thin-film superconductors. In this review article, current research in this field is described, focusing on the general theoretical concepts of non-Abelian statistics as it relates to topological quantum computation, on understanding non-Abelian quantum Hall states, on proposed experiments to detect non-Abelian anyons, and on proposed architectures for a topological quantum computer. Both the mathematical underpinnings of topological quantum computation and the physics of the subject are addressed, using the $\ensuremath{\nu}=5∕2$ fractional quantum Hall state as the archetype of a non-Abelian topological state enabling fault-tolerant quantum computation.

Non-Abelian Anyons and Topological Quantum Computation

Anyons in an exactly solved model and beyond

The phenomenon of Anderson localization is studied for a class of one-particle Schrodinger operators with random Zeeman interactions. These operators arise as follows: Static spins are placed randomly on the sites of a simple cubic lattice according to a site percolation process with density x and coupled to one another ferromagnetically. Scattering of an electron in a conduction band at these spins is described by a random Zeeman interaction term that originates from indirect exchange. It is shown rigorously that, for positive values of x below the percolation threshold, the spectrum of the one-electron Schrodinger operator near the band edges is dense pure-point, and the corresponding eigenfunctions are exponentially localized. Localization near the band edges persists in a weak external magnetic field, H, but disappears gradually, as H is increased. Our results lead us to predict the phenomenon of colossal (negative) magnetoresistance and the existence of a Mott transition, as H and/or x are increased. Our analysis is motivated directly by experimental results concerning the magnetic alloy Eu
 x
 Ca1−x
 B6.

/pdf/anderson-localization-triggered-by-spin-disorder-with-an-2zpmlzbtkg.pdf

Anderson Localization Triggered by Spin Disorder—With an Application to EuxCa1−xB6

For the reconstruction of physiological changes in specific tissue layers detected by optical techniques, the exact knowledge of the optical parameters μa, μs and g of different tissue types is of paramount importance. One approach to accurately determine these parameters for biological tissue or phantom material is to use a double-integrating-sphere measurement system. It offers a flexible way to measure various kinds of tissues, liquids and artificial phantom materials. Accurate measurements can be achieved by technical adjustments and calibration of the spheres using commercially available reflection and transmission standards. The determination
For the reconstruction of physiological changes in specific tissue layers detected by optical techniques, the exact knowledge of the optical parameters μa, μs and g of different tissue types is of paramount importance. One approach to accurately determine these parameters for biological tissue or phantom material is to use a double-integrating-sphere measurement system. It offers a flexible way to measure various kinds of tissues, liquids and artificial phantom materials. Accurate measurements can be achieved by technical adjustments and calibration of the spheres using commercially available reflection and transmission standards. The determination
of the optical parameters of a material is based on two separate steps. Firstly, the reflectance ρs, the total transmittance TsT and the unscattered transmittance TsC of the sample s are measured with the double-integrating-sphere setup. Secondly, the optical parameters μa, μs and g are reconstructed with an inverse search algorithm combined with an appropriate solver for the forward problem (calculating ρs, TsT and TsC from μa, μs and g) has to be applied. In this study a Genetic Algorithm is applied as search heuristic, since it offers the most flexible and general approach without requiring any foreknowledge of the fitness-landscape. Given the challenging preparation of real tissue samples it comes as no surprise that these are subject to various uncertainties. In order to perform a robust parameter reconstruction samples of different thickness are used. This adds a further, strong restriction to the potential results from the heuristic reconstruction algorithm.

Reconstructing optical parameters from double-integrating-sphere measurements using a genetic algorithm

Integral Quadratic Forms, Kac-Moody Algebras, and Fractional Quantum Hall Effect. An ADE-$\mathcal {O}$ Classification

We present and discuss a list of important, mostly open problems in constructive quantum field theory and equilibrium statistical mechanics the solution of which requires (in rare cases : required) new ideas going beyond high - and low - temperature expansions guided by standard (super-renormalizable and infrared finite) perturbation theory about the critical points of some action or Hamilton function, beyond Peierls-type arguments and their variants and beyond spin wave theory and its rigorous counterparts. This list of problems includes higher order phase transitions, critical phenomena, long range forces, gauge theories, quantum solitons, etc.

Some frontiers in constructive quantum field theory and equilibrium statistical mechanics

A lattice gas on ℤ3 consisting of hard spheres with exclusions extending through third neighbors is proved to undergo a percolation transition. If spins with ferromagnetic couplings are attached to the spheres, spontaneous magnetization is proved to occur. This may provide a model for a “ferrofluid,” a system which exhibits spontaneous magnetization without crystalline order. Similar results are also obtained for an analogous model on ℤ2.

Jürg Fröhlich

Papers

Anderson Localization Triggered by Spin Disorder—With an Application to EuxCa1−xB6

Reconstructing optical parameters from double-integrating-sphere measurements using a genetic algorithm

Integral Quadratic Forms, Kac-Moody Algebras, and Fractional Quantum Hall Effect. An ADE-$\mathcal {O}$ Classification

Some frontiers in constructive quantum field theory and equilibrium statistical mechanics

Percolation in hard-core lattice gases and a model ferrofluid