We review the recent developments and the current status in the field of quantum-gas cavity QED. Since the first experimental demonstration of atomic self-ordering in a system composed of a ...Bose-Einstein condensate coupled to a quantized electromagnetic mode of a high-Q optical cavity, the field has rapidly evolved over the past decade. The composite quantum-gas-cavity systems offer the opportunity to implement, simulate, and experimentally test fundamental solid-state Hamiltonians, as well as to realize non-equilibrium many-body phenomena beyond conventional condensed-matter scenarios. This hinges on the unique possibility to design and control in open quantum environments photon-induced tunable-range interaction potentials for the atoms using tailored pump lasers and dynamic cavity fields. Notable examples range from Hubbard-like models with long-range interactions exhibiting a lattice-supersolid phase, over emergent magnetic orderings and quasicrystalline symmetries, to the appearance of dynamic gauge potentials and non-equilibrium topological phases. Experiments have managed to load spin-polarized as well as spinful quantum gases into various cavity geometries and engineer versatile tunable-range atomic interactions. This led to the experimental observation of spontaneous discrete and continuous symmetry breaking with the appearance of soft-modes as well as supersolidity, density and spin self-ordering, dynamic spin-orbit coupling, and non-equilibrium dynamical self-ordered phases among others. In addition, quantum-gas-cavity setups offer new platforms for quantum-enhanced measurements. In this review, starting from an introduction to basic models, we pedagogically summarize a broad range of theoretical developments and put them in perspective with the current and near future state-of-art experiments.
Full text
Available for:
BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Autogenic spatial self‐organization can produce coherent patterns of ordered cyclical strata through interaction of system components, independent of initial conditions and without external forcing. ...Previous numerical modelling work that partially explored self‐organized cyclicity in carbonate strata is expanded, refined and tested using a different numerical model formulation of an existing carbonate forward model ‘CarboCAT’. Results show that cross‐platform sediment transport creates a series of self‐organized prograding islands and shorelines that generate upward‐shallowing autocycles, defined by strong statistical evidence for ordered facies successions. A subtidal factory in front of each shoreline supplies sediment that drives shoreline progradation and these subtidal supply‐zone widths are also self‐organized to an optimal characteristic width due to island progradation, such that an accommodation creation/sediment supply ratio of around one maintains self‐organized shoreline progradation. The resulting island progradation rate determines autocycle thickness, which is very different from the accommodation control assumed in most sequence stratigraphic and cyclostratigraphic interpretations. This self‐organization process is comparable to the reaction–diffusion model first suggested by Alan Turing. The simplest possible combination of processes that leads to self‐organization are water‐depth‐dependent production, straight long‐distance cross‐platform transport and uniform subsidence. Additional more complex processes can produce self‐organization, but also more diverse island morphologies, less ordered autocyclic strata and more variable lateral facies continuity. Exploration of the model parameter space shows that self‐organization occurs for only a limited range of accommodation creation/sediment supply ratios. The modelling is calibrated and checked for realism against shoreline progradation rates measured on the Peros Banhos carbonate platform, British Indian Ocean Territory, and a Holocene Abu Dhabi shoreline, suggesting that this is a realistic and perhaps ubiquitous process in geological history. Given the fundamental nature of processes modelled here, and the match with observed processes in modern depositional systems, it seems possible that similar autogenic, self‐organizing processes have operated on many carbonate platforms and are an important component in the stratigraphic record.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Epithelia are the first organized tissues that appear during development. In many animal embryos, early divisions give rise to a polarized monolayer, the primary epithelium, rather than a random ...aggregate of cells. Here, we review the mechanisms by which cells organize into primary epithelia in various developmental contexts. We discuss how cells acquire polarity while undergoing early divisions. We describe cases where oriented divisions constrain cell arrangement to monolayers including organization on top of yolk surfaces. We finally discuss how epithelia emerge in embryos from animals that branched early during evolution and provide examples of epithelia‐like arrangements encountered in single‐celled eukaryotes. Although divergent and context‐dependent mechanisms give rise to primary epithelia, here we trace the unifying principles underlying their formation.
Epithelia are the first organized structures to appear during animal development and evolution. Although key characteristics are shared among diverse epithelia, the mechanism they form is highly divergent. The challenge for dividing cells in the early embryo to form the primary epithelium has been resolved in unique ways across Metazoa.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Complexity science is an investigative framework that stems from a number of tried and tested disciplines—including systems theory, nonlinear dynamical systems theory, and synergetics—and extends a ...common set of concepts, methods, and principles to understand how natural systems operate. By quantitatively employing concepts, such as emergence, nonlinearity, and self‐organization, complexity science offers a way to understand the structures and operations of natural cognitive systems in a manner that is conceptually compelling and mathematically rigorous. Thus, complexity science both transforms understandings of cognition and reframes more traditional approaches. Consequently, if cognitive systems are indeed complex systems, then cognitive science ought to consider complexity science as a centerpiece of the discipline.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Organoids form through self-organization processes in which initially homogeneous populations of stem cells spontaneously break symmetry and undergo in-vivo-like pattern formation and morphogenesis, ...though the processes controlling this are poorly characterized. While these in vitro self-organized tissues far exceed the microscopic and functional complexity obtained by current tissue engineering technologies, they are non-physiological in shape and size and have limited function and lifespan. Here, we discuss how engineering efforts for guiding stem-cell-based development at multiple stages can form the basis for the assembly of highly complex and rationally designed self-organizing multicellular systems with increased robustness and physiological relevance.
Organoids form through self-organization processes in which initially homogeneous populations of stem cells spontaneously break symmetry and undergo in-vivo-like pattern formation and morphogenesis, though the processes controlling this are poorly characterized. While these in vitro self-organized tissues far exceed the microscopic and functional complexity obtained by current tissue engineering technologies, they are non-physiological in shape and size and have limited function and lifespan. Here, we discuss how engineering efforts for guiding stem-cell-based development at multiple stages can form the basis for the assembly of highly complex and rationally designed self-organizing multicellular systems with increased robustness and physiological relevance.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Human naive pluripotent cells can differentiate into extraembryonic trophectoderm and hypoblast. Here we describe a human embryo model (blastoid) generated by self-organization. Brief induction of ...trophectoderm leads to formation of blastocyst-like structures within 3 days. Blastoids are composed of three tissue layers displaying exclusive lineage markers, mimicking the natural blastocyst. Single-cell transcriptome analyses confirm segregation of trophectoderm, hypoblast, and epiblast with high fidelity to the human embryo. This versatile and scalable system provides a robust experimental model for human embryo research.
Display omitted
•Generation of human blastoids with structure and composition similar to the embryo•Segregation of trophectoderm, hypoblast, and naive epiblast lineages•Transcriptome fidelity with the embryo•Simple, efficient, and scalable procedure
Reliable stem cell models of the early embryo would open new approaches to studying human development and infertility. Yanagida and colleagues used naive stem cells to generate human blastocyst-like structures comprising the three founding tissue layers for the extraembryonic membranes and the embryo.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This review highlights the important role of the depth‐averaged sediment concentration (DASC) to understand the formation of a number of coastal morphodynamic features that have an alongshore ...rhythmic pattern: beach cusps, surf zone transverse and crescentic bars, and shoreface‐connected sand ridges. We present a formulation and methodology, based on the knowledge of the DASC (which equals the sediment load divided by the water depth), that has been successfully used to understand the characteristics of these features. These sand bodies, relevant for coastal engineering and other disciplines, are located in different parts of the coastal zone and are characterized by different spatial and temporal scales, but the same technique can be used to understand them. Since the sand bodies occur in the presence of depth‐averaged currents, the sediment transport approximately equals a sediment load times the current. Moreover, it is assumed that waves essentially mobilize the sediment, and the current increases this mobilization and advects the sediment. In such conditions, knowing the spatial distribution of the DASC and the depth‐averaged currents induced by the forcing (waves, wind, and pressure gradients) over the patterns allows inferring the convergence/divergence of sediment transport. Deposition (erosion) occurs where the current flows from areas of high to low (low to high) values of DASC. The formulation and methodology are especially useful to understand the positive feedback mechanisms between flow and morphology leading to the formation of those morphological features, but the physical mechanisms for their migration, their finite‐amplitude behavior and their decay can also be explored.
Key Points
A methodology to examine interactions between flow and morphology is presented
It is applied to beach cusps, crescentic/transverse bars and inner shelf ridges
The depth‐averaged sediment concentration is crucial in the feedback mechanisms
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Widespread anatexis was a regional response to the evolution of the Himalayan‐Tibetan Orogen that occurred some 30 Ma after collision between Asia and India. This paper reviews the nature, timing, ...duration and conditions of anatexis and leucogranite formation in the Greater Himalayan Sequence (GHS), and compares them to contemporaneous granites in the Karakoram mountains. Himalayan leucogranites and associated migmatites generally share a number of features along the length of the mountain front, such as similar timing and duration of magmatism, common source rocks and clockwise P–T paths. Despite commonalities, most papers emphasize deviations from this general pattern, indicating a fine‐tuned local response to the dominant evolution. There are significant differences in P–T–XH2O conditions during anatexis, and timing in relation to regional decompression. Further to that, some regions underwent a second event recording melting at low pressures. Zircon and monazite ages of anatectic rocks range between c. 25 and 15 Ma, suggesting prolonged crustal melting. Typically, a single sample may have ages covering most of this 10 Ma period, suggesting recycling of accessory phases from metamorphic rocks and early‐formed magmas. Recent studies linking monazite and zircon ages with their composition, have determined the timing of prograde melting and retrograde melt crystallization, thus constraining the duration of the anatectic cycle. In some areas, this cycle becomes younger down section, towards the leading front of the Himalayas, whereas the opposite is true in other areas. The relationship between granites and movement on the South Tibetan Detachment (STD) reveals that fault motion took place at different times and over different durations requiring complex internal strain distribution along the Himalayas. The nature and fate of magmas in the GHS contrast with those in the Karakoram mountains. GHS leucogranites have a strong crustal isotopic signature and migration is controlled by low‐angle foliation, leading to diffuse injection complexes concentrated below the STD. In contrast, the steep attitude of the Karakoram shear zone focused magma transfer, feeding the large Karakoram‐Baltoro batholith. Anatexis in the Karakoram involved a Cretaceous calcalkaline batholith that provided leucogranites with more juvenile isotopic signatures. The impact of melting on the evolution of the Himalayas has been widely debated. Melting has been used to explain subsequent decompression, or conversely, decompression has been used to explain melting. Weakening due to melting has also been used to support channel flow models for extrusion of the GHS, or alternatively, to suggest it triggered a change in its critical taper. In view of the variable nature of anatexis and of motion on the STD, it is likely that anatexis had only a second‐order effect in modulating strain distribution, with little effect on the general history of deformation. Thus, despite all kinds of local differences, strain distribution over time was such that it maintained the well‐defined arc that characterizes this orogen. This was likely the result of a self‐organized forward motion of the arc, controlled by the imposed convergence history and energy conservation, balancing accumulation of potential energy and dissipation, independent of the presence or absence of melt.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
PDF
