Vertical information content of nadir measurements of tropospheric NO2 from satellite

Poster presented at the EGU General Assembly 2014 in Vienna/Austria

Entanglement Spectra of Heisenberg Ladders of higher Spin

We study the entanglement spectrum of Heisenberg spin ladders of arbitrary spin length S in the perturbative regime of strong rung coupling. For isotropic spin coupling the the entanglement spectrum is, within first order perturbation theory, always proportional to the energy spectrum of the single chain with a proportionality factor being also independent of S. A more complicated situation arises for anisotropic ladders of higher spin S>=1 since here even the unperturbed ground state has a nontrivial entanglement spectrum. Finally we discuss related issues in dimerized spin chains

Plasmons and screening in a monolayer of MoS2_2

We investigate the dynamical dielectric function of a monolayer of molybdenum disulfide within the random phase approximation. While in graphene damping of plasmons is caused by interband transitions, due to the large direct band gap in monolayer MoS$_2$ collective charge excitations enter the intraband electron hole continuum similar to the situation in two-dimensional electron and hole gases. Since there is no electron-hole symmetry in MoS$_2$, the plasmon energies in p- and n-doped samples clearly differ. The breaking of spin degeneracy caused by the large intrinsic spin-orbit interaction leads to a beating of Friedel oscillations for sufficiently large carrier concentrations, for holes as well as for electrons.Comment: 7 pages, 8 figures; typos correcte

Interplay between spin-orbit interactions and a time-dependent electromagnetic field in monolayer graphene

We apply a circularly and linearly polarized terahertz field on a monolayer of graphene taking into account spin-orbit interactions of the intrinsic and Rashba type. It turns out that the field can not only be used to induce a gap in the energy spectrum, but also to close an existing gap due to the different reaction of the spin components on circularly polarized light. Signatures of spin-orbit coupling on the density of states of the driven system can be observed even for energies where the static density of states is independent of spin-orbit interactions. Furthermore it is shown that the time evolution of the spin polarization and the orbital dynamics of an initial wave packet can be modulated by varying the ratio of the spin-orbit coupling parameters. Assuming that the system acquires a quasi stationary state, the optical conductivity of the irradiated sample is calculated. Our results confirm the multi step nature of the conductivity obtained recently, where the number of intermediate steps can be changed by adjusting the spin-orbit coupling parameters and the orientation of the field.Comment: 10 pages, 11 figures; typos corrected, references adde

Influence of surface tension on the conical miniscus of a magnetic fluid in the field of a current-carrying wire

We study the influence of surface tension on the shape of the conical miniscus built up by a magnetic fluid surrounding a current-carrying wire. Minimization of the total energy of the system leads to a singular second order boundary value problem for the function $\zeta(r)$ describing the axially symmetric shape of the free surface. An appropriate transformation regularizes the problem and allows a straightforward numerical solution. We also study the effects a superimposed second liquid, a nonlinear magnetization law of the magnetic fluid, and the influence of the diameter of the wire on the free surface profile

Early postoperative interventional ASD-closure for severe atrial right to left shunt in a neonate with common arterial trunk

Although closure of an atrial septal defect (ASD II) with an occluding device in the first year of life is not a routine procedure, it is a feasible treatment, even in neonates. Case reports on the off-label use of Amplatzer devices have been repeatedly published, but there are no reports on using the Amplatzer Duct Occluder (ADO) to close an atrial septal defect in a neonate. We report on a successful catheter closure of an ASD II with ADO in a severely cyanotic neonate, seven days after surgical repair of common arterial trunk. Due to progressive cyanosis and clinical signs of right ventricular failure, which developed after common arterial trunk repair, the neonate underwent cardiac catheterization. Diastolic filling impairment of the right ventricle (right ventricle hypertrophy, pulmonary regurgitation, and residual right ventricle outflow tract obstruction) was thought to be the cause of impaired right ventricle diastolic filling, resulting in the right-to-left shunt at the atrial level. Under transesophageal echocardiographic guidance, ADO was delivered through a 5 French sheath into the atrial septal defect. Amplatzer duct occluder closed the defect and proved to be stable in position after disconnection. During the procedure, the child was stable and then transferred to the intensive care unit with significantly improved oxygen saturation. This is the first report on placing a duct occluder in the atrial septal position, which is a novel procedure for-small neonates

The entangling and disentangling power of unitary transformations are unequal

We consider two capacity quantities associated with bipartite unitary gates: the entangling and the disentangling power. For two-qubit unitaries these two capacities are always the same. Here we prove that these capacities are different in general. We do so by constructing an explicit example of a qubit-qutrit unitary whose entangling power is maximal (2 ebits), but whose disentangling power is strictly less. A corollary is that there can be no unique ordering for unitary gates in terms of their ability to perform non-local tasks. Finally we show that in large dimensions, almost all bipartite unitaries have entangling and disentangling capacities close to the maximal possible (and thus in high dimensions the difference in these capacities is small for almost all unitaries).Comment: 6 pages, 1 airfoi

Quark and lepton masses and mixing in the landscape

Even if quark and lepton masses are not uniquely predicted by the fundamental theory, as may be the case in the string theory landscape, nevertheless their pattern may reveal features of the underlying theory. We use statistical techniques to show that the observed masses appear to be representative of a scale invariant distribution, rho(m) ~ 1/m. If we extend this distribution to include all the Yukawa couplings, we show that the resulting CKM matrix elements typically show a hierarchical pattern similar to observations. The Jarlskog invariant measuring the amount of CP violation is also well reproduced in magnitude. We also apply this framework to neutrinos using the seesaw mechanism. The neutrino results are ambiguous, with the observed pattern being statistically allowed even though the framework does not provide a natural explanation for the observed two large mixing angles. Our framework highly favors a normal hierarchy of neutrino masses. We also are able to make statistical predictions in the neutrino sector when we specialize to situations consistent with the known mass differences and two large mixing angles. Within our framework, we show that with 95% confidence the presently unmeasured MNS mixing angle sin theta_{13} is larger than 0.04 and typically of order 0.1. The leptonic Jarlskog invariant is found to be typically of order 10^{-2} and the magnitude of the effective Majorana mass m_{ee} is typically of order 0.001 eV.Comment: 32 pages, 17 figures, some references adde