Incarceration of the Gravid Uterus - a Rare Condition not to be Missed.

BACKGROUND: Incarceration of a gravid uterus (IGU) is a rare manifestation in obstetrics that may be associated with serious complications. CASE: We report on a 29-year-old patient at 34+2 weeks' gestation who presented with HELLP syndrome. IGU had been initially diagnosed in our department at 23+6 weeks' gestation. Urgent cesarean section was performed taking into account the specific characteristics of IGU. A healthy premature child was born. With the prior knowledge of IGU no complications during delivery occurred and mother and child had favorable outcomes. CONCLUSION: IGU is a rare condition in pregnancy that should not be overlooked. Early diagnosis and treatment of IGU can prevent serious complications to the mother and child during pregnancy and delivery. In this report, we discuss the specific peculiarities of an incarcerated uterus that need to be considered in this regard. HINTERGRUND: Ein Uterus incarceratus ist eine seltene Manifestation in der Geburtshilfe, welche mit schwerwiegenden Komplikationen einhergehen kann. FALL: Wir berichten über eine 29-jährige Patientin, die sich mit 34+2 Schwangerschaftswochen (SSW) mit einem HELLP-Syndrom in unserer Klinik vorgestellt hat. Die Erstdiagnose des inkarzerierten Uterus wurde in unserer Klinik mit 23+6 SSW gestellt. Aufgrund unserer Vorkenntnis über diese Diagnose konnte nun die dringend indizierte Sectio caesarea unter Berücksichtigung der spezifischen Merkmale in modifizierter Technik durchgeführt werden. Es wurde ein gesundes Frühgeborenes geboren. Es traten während der Geburt keine Komplikationen auf und Mutter und Kind hatten einen günstigen Verlauf. SCHLUSSFOLGERUNG: Ein Uterus incarceratus ist eine seltene Manifestation in der Schwangerschaft, welche nicht übersehen werden sollte. Eine frühzeitige Diagnose und Behandlung kann schwerwiegende Komplikationen für Mutter und Kind während der Schwangerschaft und unter der Geburt verhindern. Wir diskutieren die spezifischen Besonderheiten eines Uterus incarceratus, die hierbei zu berücksichtigen sind.

Exotic Non-Abelian Topological Defects in Lattice Fractional Quantum Hall States.

We investigate extrinsic wormholelike twist defects that effectively increase the genus of space in lattice versions of multicomponent fractional quantum Hall systems. Although the original band structure is distorted by these defects, leading to localized midgap states, we find that a new lowest flat band representing a higher genus system can be engineered by tuning local single-particle potentials. Remarkably, once local many-body interactions in this new band are switched on, we identify various Abelian and non-Abelian fractional quantum Hall states, whose ground-state degeneracy increases with the number of defects, i.e, with the genus of space. This sensitivity of topological degeneracy to defects provides a "proof of concept" demonstration that genons, predicted by topological field theory as exotic non-Abelian defects tied to a varying topology of space, do exist in realistic microscopic models. Specifically, our results indicate that genons could be created in the laboratory by combining the physics of artificial gauge fields in cold atom systems with already existing holographic beam shaping methods for creating twist defects.

Geometric stability of topological lattice phases.

The fractional quantum Hall (FQH) effect illustrates the range of novel phenomena which can arise in a topologically ordered state in the presence of strong interactions. The possibility of realizing FQH-like phases in models with strong lattice effects has attracted intense interest as a more experimentally accessible venue for FQH phenomena which calls for more theoretical attention. Here we investigate the physical relevance of previously derived geometric conditions which quantify deviations from the Landau level physics of the FQHE. We conduct extensive numerical many-body simulations on several lattice models, obtaining new theoretical results in the process, and find remarkable correlation between these conditions and the many-body gap. These results indicate which physical factors are most relevant for the stability of FQH-like phases, a paradigm we refer to as the geometric stability hypothesis, and provide easily implementable guidelines for obtaining robust FQH-like phases in numerical or real-world experiments.

Fractional Chern Insulators in Harper-Hofstadter Bands with Higher Chern Number.

The Harper-Hofstadter model provides a fractal spectrum containing topological bands of any integer Chern number C. We study the many-body physics that is realized by interacting particles occupying Harper-Hofstadter bands with |C|>1. We formulate the predictions of Chern-Simons or composite fermion theory in terms of the filling factor ν, defined as the ratio of particle density to the number of single-particle states per unit area. We show that this theory predicts a series of fractional quantum Hall states with filling factors ν=r/(r|C|+1) for bosons, or ν=r/(2r|C|+1) for fermions. This series includes a bosonic integer quantum Hall state in |C|=2 bands. We construct specific cases where a single band of the Harper-Hofstadter model is occupied. For these cases, we provide numerical evidence that several states in this series are realized as incompressible quantum liquids for bosons with contact interactions.

Competing topological orders in the ν=12/5 quantum Hall state.

We provide numerical evidence that a p(x)-ip(y) paired Bonderson-Slingerland (BS) non-Abelian hierarchy state is a strong candidate for the observed ν=12/5 quantum Hall plateau. We confirm the existence of a gapped incompressible ν=12/5 quantum Hall state with shift S=2 on the sphere, matching that of the BS state. The exact ground state of the Coulomb interaction at S=2 is shown to have a large overlap with the BS trial wave function. Larger overlaps are obtained with BS-type wave functions that are hierarchical descendants of general p(x)-ip(y) weakly paired states at ν=5/2. We perform a finite-size scaling analysis of the ground-state energies for ν=12/5 states at shifts corresponding to the BS (S=2) and 3-clustered Read-Rezayi (S=-2) universality classes. This analysis reveals very tight competition between these two non-Abelian topological orders.

Adiabatic continuation of fractional Chern insulators to fractional quantum Hall States.

We show how the phases of interacting particles in topological flat bands, known as fractional Chern insulators, can be adiabatically connected to incompressible fractional quantum Hall liquids in the lowest Landau level of an externally applied magnetic field. Unlike previous evidence suggesting the similarity of these systems, our approach enables a formal proof of the equality of their topological orders, and furthermore this proof robustly extends to the thermodynamic limit. We achieve this result using the hybrid Wannier orbital basis proposed by Qi [Phys. Rev. Lett. 107, 126803 (2011)] in order to construct interpolation Hamiltonians that provide continuous deformations between the two models. We illustrate the validity of our approach for the ground state of bosons in the half filled Chern band of the Haldane model, showing that it is adiabatically connected to the ν=1/2 Laughlin state of bosons in the continuum fractional quantum Hall problem.

Neutral fermion excitations in the Moore-Read state at filling factor ν = 5/2.

We present evidence supporting the weakly paired Moore-Read phase in the half-filled second Landau level, focusing on some of the qualitative features of its excitations. Based on numerical studies, we show that systems with odd particle number at the flux N(ϕ)=2N-3 can be interpreted as a neutral fermion mode of one unpaired fermion, which is gapped. The mode is found to have two distinct minima, providing a signature that could be observed by photoluminescence. In the presence of two quasiparticles the same neutral fermion excitation is shown to be gapless, confirming expectations for non-abelian statistics of the Ising model with degenerate fusion channels 1 and ψ.

Skyrmions in the Moore-Read state at nu=5/2.

We study charged excitations of the non-Abelian Moore-Read liquid at a filling factor nu=5/2, allowing for spin depolarization. Using a combination of numerical studies, and taking account of nonzero well widths, we find that at a sufficiently low Zeeman energy it is energetically favorable for charge e/4 quasiholes to bind into Skyrmions of charge e/2. We show that Skyrmion formation is further promoted by disorder, and argue that this can lead to a depolarized nu=5/2 ground state in realistic experimental situations. We comment on the consequences for the activated transport.

Paired composite fermion phase of quantum Hall bilayers at nu=1/2+1/2.

We provide numerical evidence for composite fermion pairing in quantum Hall bilayer systems at filling nu=1/2+1/2 for intermediate spacing between the layers. We identify the phase as p_(x)+ip_(y) pairing, and construct high accuracy trial wave functions to describe the ground state on the sphere. For large distances between the layers, and for finite systems, a competing "Hund's rule" state, or composite fermion liquid, prevails for certain system sizes.