Field-induced transition within the superconducting state of CeRhAs.

Materials with multiple superconducting phases are rare. Here, we report the discovery of two-phase unconventional superconductivity in CeRhAs Using thermodynamic probes, we establish that the superconducting critical field of its high-field phase is as high as 14 tesla, even though the transition temperature is only 0.26 kelvin.

Time-reversal symmetry-breaking in noncentrosymmetric superconductors.

In this paper we examine the appearance of time-reversal symmetry-breaking (TRSB) states in the bulk and at the surface of a noncentrosymmetric superconductor. We utilize a Ginzburg-Landau theory, with coefficients derived from a microscopic model of the superconductor. We show that suppression of the triplet order parameter at the surface stabilizes a TRSB state by locally tuning the system into the bulk TRSB phase.

Beyond triplet: Unconventional superconductivity in a spin-3/2 topological semimetal.

In all known fermionic superfluids, Cooper pairs are composed of spin-1/2 quasi-particles that pair to form either spin-singlet or spin-triplet bound states. The "spin" of a Bloch electron, however, is fixed by the symmetries of the crystal and the atomic orbitals from which it is derived and, in some cases, can behave as if it were a spin-3/2 particle. The superconducting state of such a system allows pairing beyond spin-triplet, with higher spin quasi-particles combining to form quintet or septet pairs.

Does rectal diclofenac reduce post-ERCP pancreatitis? A district general hospital experience.

Introduction: There is controversy in the literature recently regarding the efficacy of rectal non-steroidal anti-inflammatory drugs (NSAID) to prevent post-ERCP pancreatitis (PEP). The aim of this study was to compare the incidence of PEP in three distinct groups of patients at the Royal United Hospital, Bath: no use of rectal diclofenac, selective use and blanket use without contraindication.

Method: Readmission data, blood results, radiology reports and discharge summaries were used to identify patients with PEP from August 2010 to December 2015.

Resilient Nodeless d-Wave Superconductivity in Monolayer FeSe.

Monolayer FeSe exhibits the highest transition temperature among the iron based superconductors and appears to be fully gapped, seemingly consistent with s-wave superconductivity. Here, we develop a theory for the superconductivity based on coupling to fluctuations of checkerboard magnetic order (which has the same translation symmetry as the lattice). The electronic states are described by a symmetry based k·p-like theory and naturally account for the states observed by angle resolved photoemission spectroscopy.

Bogoliubov Fermi Surfaces in Superconductors with Broken Time-Reversal Symmetry.

It is commonly believed that, in the absence of disorder or an external magnetic field, there are three possible types of superconducting excitation gaps: The gap is nodeless, it has point nodes, or it has line nodes. Here, we show that, for an even-parity nodal superconducting state which spontaneously breaks time-reversal symmetry, the low-energy excitation spectrum generally does not belong to any of these categories; instead, it has extended Bogoliubov Fermi surfaces. These Fermi surfaces can be visualized as two-dimensional surfaces generated by "inflating" point or line nodes into spheroids or tori, respectively.

Pairing of j=3/2 Fermions in Half-Heusler Superconductors.

We theoretically consider the superconductivity of the topological half-Heusler semimetals YPtBi and LuPtBi. We show that pairing occurs between j=3/2 fermion states, which leads to qualitative differences from the conventional theory of pairing between j=1/2 states. In particular, this permits Cooper pairs with quintet or septet total angular momentum, in addition to the usual singlet and triplet states.

Bound States of a Ferromagnetic Wire in a Superconductor.

We consider the problem of bound states in strongly anisotropic ferromagnetic impurities in a superconductor, motivated by recent experiments that claim to observe Majorana modes at the ends of ferromagnetic wires on a superconducting substrate [S. Nadj-Perge et al., Science 346, 602 (2014)].

Topological surface states in nodal superconductors.

Topological superconductors have become a subject of intense research due to their potential use for technical applications in device fabrication and quantum information. Besides fully gapped superconductors, unconventional superconductors with point or line nodes in their order parameter can also exhibit nontrivial topological characteristics. This article reviews recent progress in the theoretical understanding of nodal topological superconductors, with a focus on Weyl and noncentrosymmetric superconductors and their protected surface states.

Majorana fermions in ferromagnetic chains on the surface of bulk spin-orbit coupled s-wave superconductors.

Majorana fermion (MF) excitations in solid state system have non-Abelian statistics which is essential for topological quantum computation. Previous proposals to realize MF, however, generally requires fine-tuning of parameters. Here we explore a platform which avoids the fine-tuning problem, namely a ferromagnetic chain deposited on the surface of a spin-orbit coupled s-wave superconductor.

Spin-orbital coupling in a triplet superconductor-ferromagnet junction.

We study the interplay of spin and orbital degrees of freedom in a triplet superconductor-ferromagnet junction. Using a self-consistent spatially dependent mean-field theory, we show that increasing the angle between the ferromagnetic moment and the triplet vector order parameter enhances or suppresses the p-wave gap close to the interface, according to whether the gap antinodes are parallel or perpendicular to the boundary, respectively. The associated change in condensation energy establishes an orbitally dependent preferred orientation for the magnetization.

Edge currents as a signature of flatbands in topological superconductors.

We study nondegenerate flatbands at the surfaces of noncentrosymmetric topological superconductors by exact diagonalization of Bogoliubov-de Gennes Hamiltonians. We show that these states are strongly spin polarized and acquire a chiral dispersion when placed in contact with a ferromagnetic insulator. This chiral mode carries a large edge current which displays a singular dependence on the exchange-field strength.

The Josephson effect between triplet superconductors through a finite ferromagnetic barrier.

Charge and spin transport in a junction involving two triplet superconductors and a ferromagnetic barrier are studied. We use Bogoliubov-de Gennes wavefunctions to construct the Green's function, from which we obtain the Josephson currents in terms of the Andreev reflection coefficients. We focus on the consequences of a finite barrier width for the occurrence of 0-π transitions and for the spin currents, and examine the appropriateness of the common δ-function approximation for the tunneling region.

Magnetic order in orbital models of the iron pnictides.

We examine the appearance of the experimentally observed stripe spin-density-wave magnetic order in five different orbital models of the iron pnictide parent compounds. A restricted mean-field ansatz is used to determine the magnetic phase diagram of each model. Using the random phase approximation, we then check this phase diagram by evaluating the static spin susceptibility in the paramagnetic state close to the mean-field phase boundaries.

Functional superconductor interfaces from broken time-reversal symmetry.

The breaking of time-reversal symmetry in a triplet superconductor Josephson junction is shown to cause a magnetic instability of the tunneling barrier. Using a Ginzburg-Landau analysis of the free energy, we predict that this novel functional behavior reflects the formation of an exotic Josephson state, distinguished by the existence of fractional flux quanta at the barrier. The crucial role of the orbital pairing state is demonstrated by studying complementary microscopic models of the junction.

0-pi transition in magnetic triplet superconductor josephson junctions.

We examine a Josephson junction involving two arbitrary equal-spin-pairing unitary triplet superconductors and a ferromagnetic tunneling barrier. Using perturbation theory, we show how the interaction of the barrier moment with the spin of the tunneling triplet Cooper pairs can reverse the sign of the Josephson charge current. This also results in a Josephson spin current, which contains a phase-independent contribution due to reflection processes at the barrier.

Correlation of physician seniority with increased emergency department efficiency during a resident doctors' strike.

Aim: Physician seniority has increasingly been shown to correlate with improved clinical outcomes. However few studies examine the relationship between treating doctor experience and the efficiency of emergency care systems. We explored the hypothesis that increased seniority of emergency department (ED) medical staff would result in improved ED efficiency.

Bosonization solution of the Falicov-Kimball model.

We use a novel approach to analyze the one-dimensional spinless Falicov-Kimball model. We derive a simple effective model for the occupation of the localized orbitals which clearly reveals the origin of the known ordering. Our study is extended to a quantum model with hybridization between the localized and itinerant states: We find a crossover between the well-known weak- and strong-coupling behaviors.

A comparison of foetal and labour outcomes in Caucasian and Afro-Caribbean women with diabetes in pregnancy.

Materno-foetal complications have an increased prevalence in pregnancies complicated by diabetes. Ethnicity and cultural background may further affect these outcomes. In this study, we compared labour and foetal outcomes in Afro-Caribbean and Caucasian women with diabetes in pregnancy, using the Birmingham computerised database of diabetes in pregnancy.

Pregnancy in women with Type 2 diabetes: 12 years outcome data 1990-2002.

Aim: Twelve years' outcome analysis of pregnancies in women with Type 2 diabetes in a multiethnic geographically defined area.

Methods: Information about 182 women delivered between 1990 and 2002 was ascertained from a regional computerized database. The main outcome measures were rates of miscarriage, stillbirth, neonatal/postnatal deaths, congenital malformations, birth weight, mode of delivery, and neonatal unit care as well as maternal morbidities of polyhydramnios, postpartum haemorrhage, pregnancy-induced hypertension/pre-eclampsia.

Changes in plasma lipids and markers of oxidative stress in normal pregnancy and pregnancies complicated by diabetes.

The purpose of the present study was to determine changes in plasma lipids and markers of oxidative stress longitudinally in pregnancy complicated by diabetes compared with non-diabetic pregnancy. This was carried out by following a group of normal pregnant women (n=17) and groups of pregnant women with Type I diabetes (n=19), Type II diabetes (n=12) and gestational diabetes mellitus (n=12) throughout pregnancy, with sampling carried out at the end of each trimester. Serum total cholesterol and triacylglycerols (triglycerides) were determined using standard colorimetric techniques and low-density lipoprotein (LDL) subfraction profile by disc PAGE.

Maternal ante-natal parameters as predictors of persistent postnatal glucose intolerance: a comparative study between Afro-Caribbeans, Asians and Caucasians.

Aims: To measure the prevalence of persistent glucose intolerance at 6-12 weeks postpartum in various ethnic groups to assess the value of targeted postpartum screening.

Methods: A retrospective study was performed using computerized databases from two large maternity units within one UK region. Both units used the same screening strategy for gestational diabetes mellitus (GDM) and the same postpartum follow-up at 6-12 weeks using a 75-g oral glucose tolerance test (OGTT).