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Diffusion of hydrogen within idealised grains of bcc-Fe: A kinetic Monte Carlo studyJun 11 2012Structural defects in materials such as vacancies, grain boundaries, and dislocations may trap hydrogen and a local accumulation of hydrogen at these defects can lead to the degradation of the materials properties. An important aspect in obtaining insight ... More

First-principles statistical mechanics study of the stability of a sub-nanometer thin surface oxide in reactive environments: CO oxidation at Pd(100)Sep 05 2006We employ a multiscale modeling approach to study the surface structure and composition of a Pd(100) model catalyst in reactive environments. Under gas phase conditions representative of technological CO oxidation (~1 atm, 300-600 K) we find the system ... More

Density-functional theory investigation of oxygen adsorption at Pd(11N)(N=3,5,7) vicinal surfacesJun 01 2006We present a density-functional theory study addressing the on-surface adsorption of oxygen at the Pd(11N) (N =3,5,7) vicinal surfaces, which exhibit (111) steps and (100) terraces of increasing width. We find the binding to be predominantly governed ... More

CO oxidation at Pd(100): A first-principles constrained thermodynamics studyJan 31 2007The possible formation of oxides or thin oxide films (surface oxides) on late transition metal surfaces is recently being recognized as an essential ingredient when aiming to understand catalytic oxidation reactions under technologically relevant gas ... More

Neural network based path collective variables for enhanced sampling of phase transformationsMay 04 2019We propose a rigorous construction of a 1D path collective variable to sample structural phase transformations in condensed matter. The path collective variable is defined in a space spanned by global collective variables that serve as classifiers derived ... More

On the thermodynamic stability of PdO surfacesOct 10 2003As a first step towards understanding the morphology of PdO crystals we performed a systematic full-potential density-functional theory study of all possible 1 x 1 terminations of the low-index surfaces of tetragonal PdO. Applying the concept of first-principles ... More

Kinetic Monte Carlo simulations of vacancy diffusion in non-dilute Ni-X (X=Re,W,Ta) alloysDec 12 2018The mobility of vacancies in alloys may limit dislocation climb. Using a combined density functional theory and kinetic Monte Carlo approach we investigate vacancy diffusion in Ni-Re, Ni-W, and Ni-Ta binary alloys up to 10 at.% solute concentration. We ... More

Effect of surface nanostructure on temperature programmed reaction spectroscopy: First-principles kinetic Monte Carlo simulations of CO oxidation at RuO2(110)Nov 15 2007Using the catalytic CO oxidation at RuO2(110) as a showcase, we employ first-principles kinetic Monte Carlo simulations to illustrate the intricate effects on temperature programmed reaction spectroscopy data brought about by the mere correlations between ... More

CO oxidation on Pd(100) at technologically relevant pressure conditions: A first-principles kinetic Monte Carlo studyFeb 05 2008The possible importance of oxide formation for the catalytic activity of transition metals in heterogenous oxidation catalysis has evoked a lively discussion over the recent years. On the more noble transition metals (like Pd, Pt or Ag) the low stability ... More

Accelerating spin-space sampling by auxiliary spin-dynamics and temperature-dependent spin-cluster expansionFeb 06 2019Atomistic simulations of thermodynamic properties of magnetic materials rely on an accurate modelling of magnetic interactions and an efficient sampling of the high-dimensional spin space. Recent years have seen significant progress with a clear trend ... More

First principles characterization of reversible martensitic transformationsOct 12 2018Oct 15 2018Reversible martensitic transformations (MTs) are the origin of many fascinating phenomena, including the famous shape memory effect. In this work, we present a fully ab initio procedure to characterize MTs in alloys and to assess their reversibility. ... More

Higher Mellin moments for charged current DISJun 22 2007We report on our recent results for deep-inelastic neutrino-proton scattering. We have computed the perturbative QCD corrections to three loops for the harged current structure functions F_2, F_L and F_3 for the combination nu P - nubar P. In leading ... More

Charged current deep-inelastic scattering at three loopsApr 13 2007We derive for deep-inelastic neutrino-proton scattering in the combination nu P - nubar P the perturbative QCD corrections to three loops for the charged current structure functions F_2, F_L and F_3. In leading twist approximation we calculate the first ... More

Black Holes in Higher Dimensions (Black Strings and Black Rings)Sep 16 2013The main focus of this session was the presentation of new higher-dimensional black hole solutions, including black rings, black strings, and multi black holes, and the study of their properties. Besides new asymptotically flat and locally asymptotically ... More

Partial Dynamical Symmetry in a Fermionic Many-Body SystemAug 31 2000The concept of partial symmetry is introduced for an interacting fermion system. The associated Hamiltonians are shown to be closely related to a realistic nuclear quadrupole-quadrupole interaction. An application to $^{12}$C is presented.

Comparison of the full-potential and frozen-core approximation approaches to density-functional calculations of surfacesSep 01 2005We scrutinize the accuracy of the pseudopotential approximation in density-functional theory (DFT) calculations of surfaces by systematically comparing to results obtained within a full-potential setup. As model system we choose the CO oxidation at a ... More

Unusual composition dependence of transformation temperatures in Ti-Ta-X shape memory alloysApr 12 2018Ti-Ta-X (X = Al, Sn, Zr) compounds are emerging candidates as high-temperature shape memory alloys (HTSMAs). The stability of the one-way shape memory effect (1WE), the exploitable pseudoelastic (PE) strain intervals as well as the transformation temperature ... More

Phase transitions in titanium with an analytic bond-order potentialMay 03 2019Titanium is the base material for a number of technologically important alloys for energy conversion and structural applications. Atomic-scale studies of Ti-based metals employing first-principles methods, such as density functional theory, are limited ... More

Virtual three-loop corrections to Higgs boson production in gluon fusion for finite top quark massJul 17 2009In this letter we present the three-loop virtual corrections to the Higgs boson production in the gluon fusion channel where finite top quark mass effects are taken into account. We perform an asymptotic expansion and manage to evaluate five terms in ... More

Production of scalar and pseudo-scalar Higgs bosons to next-to-next-to-leading order at hadron collidersJul 18 2011We consider the production of intermediate-mass CP-even and CP-odd Higgs bosons in proton-proton and proton-anti-proton collisions. We extend the recently published results for the complete next-to-next-to-leading order calculation for a scalar Higgs ... More

Finite top quark mass effects in NNLO Higgs boson production at LHCNov 24 2009We present next-to-next-to-leading order corrections to the inclusive production of the Higgs bosons at the CERN Large Hadron Collider (LHC) including finite top quark mass effects. Expanding our analytic results for the partonic cross section around ... More

Differences between charged-current coefficient functionsAug 28 2007Second- and third-order results are presented for the structure functions of charged-current deep-inelastic scattering in the framework of massless perturbative QCD. We write down the two-loop differences between the corresponding crossing-even and -odd ... More

Beyond Heavy Top Limit In Higgs Boson Production At LHCMay 17 2010QCD corrections to inclusive Higgs boson production at the LHC are evaluated at next-to-next-to leading order. By performing asymptotic expansion of the cross section near the limit of infinitely heavy top quark we obtained a few first top mass-suppressed ... More

Discovery of new stable and high-temperature Ti-Ta-X shape memory alloys from first principles calculationsMay 14 2019In conventional Ti-Ta shape memory alloys (SMAs), high (>100{\deg}C) transformation temperatures cannot be achieved without compromising the stability of the shape memory effect. A solution to this problem is the addition of other elements to form Ti-Ta-X ... More

Discovery of new stable and high-temperature Ti-Ta-X shape memory alloys from first principles calculationsMay 14 2019Jul 24 2019In conventional Ti-Ta shape memory alloys (SMAs), high (>100{\deg}C) transformation temperatures cannot be achieved without compromising the stability of the shape memory effect. A solution to this problem is the addition of other elements to form Ti-Ta-X ... More

Discovery of $ω$-free high-temperature Ti-Ta-X shape memory alloys from first principles calculationsMay 14 2019Aug 01 2019The rapid degradation of the functional properties of many Ti-based alloys is due to the precipitation of the $\omega$ phase. In the conventional high-temperature shape memory alloy Ti-Ta the formation of this phase compromises completely the shape memory ... More

Interior of Nonuniform Black StringsOct 09 2007We consider nonuniform black strings inside their event horizon. We present numerical evidence, that the singularity touches the horizon as the horizon topology changing transition is reached.

Level Crossing Along Sphaleron BarriersMar 03 1994In the electroweak sector of the standard model topologically inequivalent vacua are separated by finite energy barriers, whose height is given by the sphale\-ron. For large values of the Higgs mass there exist several sphaleron solutions and the barriers ... More

The Sphaleron Barrier in the Presence of FermionsAug 18 1993We calculate the minimal energy path over the sphaleron barrier in the pre\-sen\-ce of fermions, assuming that the fermions of a doublet are degenerate in mass. This allows for spherically symmetric ans\"atze for the fields, when the mixing angle dependence ... More

Black Holes in Higher Dimensions (Black Strings and Black Rings)Mar 23 2016Apr 01 2016The last three years have again seen new exciting developments in the area of higher dimensional black objects. For black objects with noncompact higher dimensions, the solution space was exlored further within the blackfold approach and with numerical ... More

Comments on `Existence of axially symmetric solutions in SU(2)-Yang Mills and related theories [hep-th/9907222]'Sep 14 1999In [hep-th/9907222] Hannibal claims to exclude the existence of particle-like static axially symmetric non-abelian solutions in SU(2) Einstein-Yang-Mills-dilaton theory. His argument is based on the asymptotic behaviour of such solutions. Here we disprove ... More

Static Axially Symmetric Einstein-Yang-Mills-Dilaton Solutions: I.Regular SolutionsJul 19 1997We discuss the static axially symmetric regular solutions, obtained recently in Einstein-Yang-Mills and Einstein-Yang-Mills-dilaton theory [1]. These asymptotically flat solutions are characterized by the winding number $n>1$ and the node number $k$ of ... More

Charged black holes on a Kaluza-Klein bubbleNov 05 2008We construct a solution of two black holes on a Kaluza-Klein bubble in Einstein-Maxwell-dilaton theory. We explore the consequences of the presence of charge for the properties of this solution, and obtain a generalized Smarr relation and first law.

Partial dynamical symmetry in a fermion systemFeb 15 2000The relevance of the partial dynamical symmetry concept for an interacting fermion system is demonstrated. Hamiltonians with partial SU(3) symmetry are presented in the framework of the symplectic shell-model of nuclei and shown to be closely related ... More

Static Axially Symmetric Einstein-Yang-Mills-Dilaton Solutions: II.Black Hole SolutionsDec 22 1997We discuss the new class of static axially symmetric black hole solutions obtained recently in Einstein-Yang-Mills and Einstein-Yang-Mills-dilaton theory. These black hole solutions are asymptotically flat and they possess a regular event horizon. The ... More

Axially Symmetric Multisphalerons in Yang-Mills-Dilaton TheorySep 23 1996We construct sequences of axially symmetric multisphaleron solutions in SU(2) Yang-Mills-dilaton theory. The sequences are labelled by a winding number $n>1$. For $n=1$ the known sequence of spherically symmetric sphaleron solutions is obtained. The solutions ... More

On Axially Symmetric Solutions in the Electroweak TheoryMar 30 1994We present the general ansatz, the energy density and the Chern-Simons charge for static axially symmetric configurations in the bosonic sector of the electroweak theory. Containing the sphaleron, the multisphalerons and the sphaleron-antisphaleron pair ... More

Fermions in the background of the sphaleron barrierFeb 26 1993We demonstrate the level crossing phenomenon for fermions in the background field of the sphaleron barrier, by numerically determining the fermion eigenvalues along the minimal energy path from one vacuum to another. We assume that the fermions of a doublet ... More

A Monopole-Antimonopole Solution of the SU(2) Yang-Mills-Higgs ModelSep 07 1999As shown by Taubes, in the Bogomol'nyi-Prasad-Sommerfield limit the SU(2) Yang-Mills-Higgs model possesses smooth finite energy solutions, which do not satisfy the first order Bogomol'nyi equations. We construct numerically such a non-Bogomol'nyi solution, ... More

Static black hole solutions with axial symmetryApr 23 1997We construct a new class of asymptotically flat black hole solutions in Einstein-Yang-Mills and Einstein-Yang-Mills-dilaton theory. These black hole solutions are static, and they have a regular event horizon. However, they possess only axial symmetry. ... More

Multisphalerons in the Weinberg-Salam TheoryMay 26 1994We construct multisphaleron solutions in the Weinberg-Salam theory. The multisphaleron solutions carry Chern-Simons charge $n/2$, where $n$ is an integer, counting the winding of the fields in the azimuthal angle. The well-known sphaleron has $n=1$. The ... More

Partial Dynamical Symmetry in the Symplectic Shell ModelOct 11 2001We present an example of a partial dynamical symmetry (PDS) in an interacting fermion system and demonstrate the close relationship of the associated Hamiltonians with a realistic quadrupole-quadrupole interaction, thus shedding new light on this important ... More

Static Axially Symmetric Einstein-Yang-Mills-dilaton solutions: Addendum Asymptotic solutionsSep 22 1999We discuss the asymptotic form of the static axially symmetric, globally regular and black hole solutions, obtained recently in Einstein-Yang-Mills and Einstein-Yang-Mills-dilaton theory.

Static Axially Symmetric Solutions of Einstein-Yang-Mills-Dilaton TheoryDec 10 1996We construct static axially symmetric solutions of SU(2) Einstein-Yang-Mills-dilaton theory. Like their spherically symmetric counterparts, these solutions are nonsingular and asymptotically flat. The solutions are characterized by the winding number ... More

Gradient Approach to the Sphaleron BarrierSep 29 1994Sep 30 1994We apply the gradient approach to obtain a path over the sphaleron barrier and to demonstrate the fermionic level crossing phenomenon. Neglecting the mixing angle dependence and assuming that the fermions of a doublet are degenerate in mass we employ ... More

Electroweak bubbles and sphaleronsApr 15 1993We consider non-perturbative solutions of the Weinberg-Salam model at finite temperature. We employ an effective temperature-dependent potential yielding a first order phase transition. In the region of the phase transition, there exist two kinds of static, ... More

Multisphalerons in the Weak InteractionsMar 15 1994We construct multisphaleron solutions in the weak interactions. The multisphaleron solutions carry Chern-Simons charge $n/2$, where $n$ is an integer. The well-known sphaleron has $n=1$ and is spherically symmetric for vanishing mixing angle. In contrast ... More

Rotating Ellis Wormholes in Four DimensionsSep 04 2014We present rotating wormhole solutions in General Relativity, which are supported by a phantom scalar field. These solutions evolve from the static Ellis wormhole, when the throat is set into rotation. As the rotational velocity increases, the throat ... More

Supersymmetric rotating black hole spacetime tested by geodesicsDec 23 2013We present the complete analytical solution of the geodesics equations in the supersymmetric BMPV spacetime \cite{Breckenridge:1996is}. We study systematically the properties of massive and massless test particle motion. We analyze the trajectories with ... More

Microscopic substructure effects in potential-model descriptions of the $^7$Be$(p,γ)^8$B reactionJul 28 2000The spectroscopic factor arises from short-range effects in the nuclear wave function. On the other hand, cross sections for external capture reactions, such as $^7$Be$(p,\gamma)^8$B at low energies, depend primarily on the asymptotic normalization of ... More

Heavy quark pair production in gluon fusion at next-to-next-to-leading ${\cal O}(α_s^4)$ order: One-loop squared contributionsSep 23 2008Nov 19 2008We calculate the next-to-next-to-leading order ${\cal O}(\alpha_s^4)$ one-loop squared corrections to the production of heavy-quark pairs in the gluon-gluon fusion process. Together with the previously derived results on the $q \bar{q}$ production channel ... More

Towards the NNLO evolution of polarised parton distributionsJul 08 2008We report on the first calculation of the structure function g_1 in polarised deep-inelastic scattering to the third order in massless perturbative QCD. The calculation follows the dispersive approach already used for the corresponding unpolarised cases ... More

Negative Horizon Mass for Rotating Black HolesOct 02 2006Charged rotating black holes of Einstein-Maxwell-Chern-Simons theory in odd dimensions, $D \ge 5$, may possess a negative horizon mass, while their total mass is positive. This surprising feature is related to the existence of counterrotating solutions, ... More

Non-uniqueness, Counterrotation, and Negative Horizon Mass of Einstein-Maxwell-Chern-Simons Black HolesOct 06 2006Stationary black holes in 5-dimensional Einstein-Maxwell-Chern-Simons theory possess surprising properties. When considering the Chern-Simons coefficient $\lambda$ as a parameter, two critical values of $\lambda$ appear: the supergravity value $\lambda_{\rm ... More

D=5 Einstein-Maxwell-Chern-Simons Black HolesOct 28 20055-dimensional Einstein-Maxwell-Chern-Simons theory with Chern-Simons coefficient $\lambda=1$ has supersymmetric black holes with vanishing horizon angular velocity, but finite angular momentum. Here supersymmetry is associated with a borderline between ... More

Neutron capture cross sections from surrogate reaction data and theory: connecting the pieces with a Markov-Chain Monte Carlo approachMay 07 2019The neutron capture cross section for $^{90}Zr(n, \gamma)$ has recently been determined using surrogate $^{92}Zr(p, d\gamma)$ data and nuclear reaction theory. That work employed an approximate fitting method based on Bayesian Monte Carlo sampling to ... More

Magnetized Black Holes in an External Gravitational FieldApr 15 2017We obtain a family of exact solutions describing magnetized black holes in an external gravitational field. Locally the solutions can be interpreted as representing the near-horizon region of a black hole, which interacts with a surrounding matter distribution ... More

Rotating black holes with non-Abelian hairSep 23 2016We here review asymptotically flat rotating black holes in the presence of non-Abelian gauge fields. Like their static counterparts these black holes are no longer uniquely determined by their global charges. In the case of pure SU(2) Yang-Mills fields, ... More

Scalarized Hairy Black HolesMar 05 2015In the presence of a complex scalar field scalar-tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and ordinary hairy ... More

Charged Balanced Black Rings in Five DimensionsDec 22 2010We present balanced black ring solutions of pure Einstein-Maxwell theory in five dimensions. The solutions are asymptotically flat, and their tension and gravitational self-attraction are balanced by the repulsion due to rotation and electrical charge. ... More

Electroweak Sphalerons with Spin and ChargeOct 07 2008We show that, at finite weak mixing angle the sphaleron solution of Weinberg-Salam theory can be endowed with angular momentum proportional to the electric charge. Carrying baryon number 1/2 these sphalerons with spin and charge may contribute to baryon ... More

Higher dimensional rotating black holes in Einstein-Maxwell theory with negative cosmological constantFeb 15 2007We present arguments for the existence of charged, rotating black holes with equal-magnitude angular momenta in an odd number of dimensions $D\geq 5$. These solutions posses a regular horizon of spherical topology and approach asymptotically the Anti-de ... More

Stable Lorentzian Wormholes in Dilatonic Einstein-Gauss-Bonnet TheoryNov 17 2011Mar 21 2012We discuss the properties of Lorentzian wormholes in dilatonic Einstein-Gauss-Bonnet theory in four spacetime dimensions. These wormholes do not need any form of exotic matter for their existence. A subset of these wormholes is shown to be linearly stable ... More

Dilatonic monopoles and ''hairy'' black holesJun 25 2001Sep 13 2001We study gravitating monopoles and non-abelian black holes of SU(2) Einstein-Yang-Mills-Higgs theory coupled to a massless dilaton. The domain of existence of these solutions decreases with increasing dilaton coupling constant. The critical solutions ... More

Gravitating Monopole-Antimonopole Systems at Large Scalar CouplingMar 26 2007We discuss static axially symmetric solutions of SU(2) Einstein-Yang-Mills-Higgs theory for large scalar coupling. These regular asymptotically flat solutions represent monopole-antimonopole chain and vortex ring solutions, as well as new configurations, ... More

Black rings in more than five dimensionsMay 24 2012We construct balanced black ring solutions in $d\geq 6$ spacetime dimensions, by solving the Einstein field equations numerically with suitable boundary conditions. The black ring solutions have a regular event horizon with $S^1\times S^{d-3}$ topology, ... More

From black strings to black holes: nuttier and squashed AdS$_5$ solutionsApr 09 2009We construct new solutions of the Einstein equations with negative cosmological constant in five spacetime dimensions. They smoothly emerge as deformations of the known AdS$_5$ black strings. The first type of configurations can be viewed as the $d=4$ ... More

On the Structure of Rotating Charged Boson StarsJan 31 2019In this work we present full sets of solutions for rotating charged boson stars with different coupling values. By adopting local comoving coordinates, we are able to find expressions for the effective hydrodynamic quantities of the fluids as seen by ... More

Effective low-energy Hamiltonians for interacting nanostructuresFeb 12 2010We present a functional renormalization group (fRG) treatment of trigonal graphene nanodiscs and composites thereof, modeled by finite-size Hubbard-like Hamiltonians with honeycomb lattice structure. At half filling, the noninteracting spectrum of these ... More

Rotating Black Holes in Higher DimensionsOct 11 2007Nov 07 2007The properties of higher-dimensional black holes can differ significantly from those of black holes in four dimensions, since neither the uniqueness theorem, nor the staticity theorem or the topological censorship theorem generalize to higher dimensions. ... More

Non-Abelian Einstein-Born-Infeld Black HolesApr 18 2000Apr 28 2000We construct regular and black hole solutions in SU(2) Einstein-Born-Infeld theory. These solutions have many features in common with the corresponding SU(2) Einstein-Yang-Mills solutions. In particular, sequences of neutral non-abelian solutions tend ... More

SU(3) Einstein-Yang-Mills-Dilaton Sphalerons and Black HolesOct 11 1995SU(3) Einstein-Yang-Mills-dilaton theory possesses sequences of static spherically symmetric sphaleron and black hole solutions for the SU(2) and the SO(3) embedding. The solutions depend on the dilaton coupling constant $\gamma$, approaching the corresponding ... More

Charged Rotating Black Holes in Higher DimensionsDec 22 2010In recent years higher-dimensional black holes have attracted much interest because of various developments in gravity and high energy physics. But whereas higher-dimensional charged static (Tangherlini) and uncharged rotating (Myers-Perry) black holes ... More

Stable Phases of Boson StarsSep 27 2011We analyze the physical properties of boson stars, which possess counterparts in flat space-time, Q-balls. Applying a stability analysis via catastrophe theory, we show that the families of rotating and non-rotating boson stars exhibit two stable regions, ... More

Static Orbits in Rotating SpacetimesNov 14 2017Dec 01 2017We show that under certain conditions an axisymmetric rotating spacetime contains a ring of points in the equatorial plane, where a particle at rest with respect to an asymptotic static observer remains at rest in a static orbit. We illustrate the emergence ... More

Multiorbital effects in the functional renormalization group: A weak-coupling study of the Emery modelOct 11 2013Dec 12 2013We perform an instability analysis of the Emery three-band model at hole doping and weak coupling within a channel-decomposed functional renormalization group flow proposed in Phys. Rev. B 79, 195125 (2009). In our approach, momentum dependences are taken ... More

Black ringoids: spinning balanced black objects in $d\geq 5$ dimensions -- the codimension-two caseOct 02 2014Dec 23 2014We propose a general framework for the study of asymptotically flat black objects with $k+1$ equal magnitude angular momenta in $d\geq 5$ spacetime dimensions (with $0\leq k\leq \big[\frac{d-5}{2} \big]$). In this approach, the dependence on all angular ... More

Spinning gauged boson stars in anti-de Sitter spacetimeOct 21 2013We study axially symmetric solutions of the Einstein-Maxwell-Klein-Gordon equations describing spinning gauged boson stars in a 3+1 dimensional asymptotically AdS spacetime. These smooth horizonless solutions possess an electric charge and a magnetic ... More

$d\geq 5$ static black holes with $S^2\times S^{d-4}$ event horizon topologyApr 17 2009We present numerical evidence for the existence of new black hole solutions in $d\geq 6$ spacetime dimensions. They approach asymptotically the Minkowski background and have an event horizon topology $S^2\times S^{d-4}$. These static solutions share the ... More

Generalized Weyl solutions in d=5 Einstein-Gauss-Bonnet theory: the static black ringDec 09 2009We argue that the Weyl coordinates and the rod-structure employed to construct static axisymmetric solutions in higher dimensional Einstein gravity can be generalized to the Einstein-Gauss-Bonnet theory. As a concrete application of the general formalism, ... More

Limiting solutions of sequences of globally regular and black hole solutions in SU(N)-EYMD theoriesOct 08 1997Static spherically symmetric solutions in SU(N)-EYM and EYMD theories are classified by the node numbers of their non-trivial gauge field functions. With increasing node numbers, the solutions form sequences, tending to limiting solutions. The limiting ... More

SU(3) Einstein-Skyrme Solitons and Black HolesMar 13 1995In the SU(3) Einstein-Skyrme system static spherically symmetric particle-like solutions and black holes exist for both the SU(2) and the SO(3) embedding. The SO(3) embedding leads to new particle-like solutions and black holes, sharing many features ... More

Myers-Perry Black Hole in an External Gravitational FieldDec 17 2014We obtain a new exact solution of the 5D Einstein equations in vacuum describing a distorted Myers-Perry black hole with a single angular momentum. Locally, the solution is interpreted as a black hole distorted by a stationary $U(1)\times U(1)$ symmetric ... More

Spinning Wormholes in Scalar-Tensor TheoryFeb 01 2018We consider spinning generalizations of the Ellis wormhole in scalar-tensor theory. Analogous to other compact objects these wormholes can carry a non-trivial scalarization. We determine the domain of existence of the scalarized wormholes and investigate ... More

Quadrupole Moments of Rapidly Rotating Compact Objects in Dilatonic Einstein-Gauss-Bonnet TheoryJul 25 2014We consider rapidly rotating black holes and neutron stars in dilatonic Einstein-Gauss-Bonnet (EGBd) theory and determine their quadrupole moments, which receive a contribution from the dilaton. The quadrupole moment of EGBd black holes can be considerably ... More

Spinning Gravitating SkyrmionsAug 25 2006We investigate self-gravitating rotating solutions in the Einstein-Skyrme theory. These solutions are globally regular and asymptotically flat. We present a new kind of solutions with zero baryon number, which possess neither a flat limit nor a static ... More

Charged Rotating Black Holes in Odd DimensionsMay 06 2006We consider charged rotating black holes in $D=2N+1$ dimensions, $D \ge 5$. While these black holes generically possess $N$ independent angular momenta, associated with $N$ distinct planes of rotation, we here focus on black holes with equal-magnitude ... More

Platonic Gravitating SkyrmionsJan 24 2006We construct globally regular gravitating Skyrmions, which possess only discrete symmetries. In particular, we present tetrahedral and cubic Skyrmions. The SU(2) Skyrme field is parametrized by an improved harmonic map ansatz. Consistency then requires ... More

Rotating Boson Stars and Q-BallsMay 29 2005We consider axially symmetric, rotating boson stars. Their flat space limits represent spinning Q-balls. We discuss their properties and determine their domain of existence. Q-balls and boson stars are stationary solutions and exist only in a limited ... More

Axially Symmetric Monopoles and Black Holes in Einstein-Yang-Mills-Higgs TheoryAug 17 2001We investigate static axially symmetric monopole and black hole solutions with magnetic charge n > 1 in Einstein-Yang-Mills-Higgs theory. For vanishing and small Higgs selfcoupling, multimonopole solutions are gravitationally bound. Their mass per unit ... More

Nondegenerate Fermions in the Background of the Sphaleron BarrierJul 21 1995We consider level crossing in the background of the sphaleron barrier for nondegenerate fermions. The mass splitting within the fermion doublets allows only for an axially symmetric ansatz for the fermion fields. In the background of the sphaleron we ... More

Stationary Black Holes with Static and Counterrotating HorizonsSep 17 2003We show that rotating dyonic black holes with static and counterrotating horizon exist in Einstein-Maxwell-dilaton theory when the dilaton coupling constant exceeds the Kaluza-Klein value. The black holes with static horizon bifurcate from the static ... More

Dyons with axial symmetryApr 14 2000May 05 2000We construct axially symmetric dyons in SU(2) Yang-Mills-Higgs theory. In the Prasad-Sommerfield limit, they are obtained via scaling relations from axially symmetric multimonopole solutions. For finite Higgs self-coupling they are constructed numerically. ... More

Excited Boson StarsAug 07 2017Axisymmetric rotating radially excited boson stars are analyzed. For several fixed parameter sets, the full sets of solutions are obtained. In contrast to the nodeless boson stars, the radially excited sets of solutions do not exhibit a spiraling behavior. ... More

Platonic Sphalerons in the Presence of a Dilaton FieldOct 25 2004We construct sphaleron solutions with discrete symmetries in Yang-Mills-Higgs theory coupled to a dilaton. Related to rational maps of degree N, these platonic sphalerons can be assigned a Chern-Simons number Q=N/2. We present sphaleron solutions with ... More

Non-perturbative conserving approximations and Luttinger's sum ruleApr 02 2007Jul 04 2007Weak-coupling conserving approximations can be constructed by truncations of the Luttinger-Ward functional and are well known as thermodynamically consistent approaches which respect macroscopic conservation laws as well as certain sum rules at zero temperature. ... More

SU(3) Einstein-Yang-Mills Sphalerons and Black HolesApr 10 1995In the SU(3) Einstein-Yang-Mills system sequences of static spherically symmetric regular solutions and black hole solutions exist for both the SU(2) and the SO(3) embedding. We construct the lowest regular solutions of the SO(3) embedding, missed previously, ... More

Geodesic Motion in the (Charged) Doubly Spinning Black Ring SpacetimeDec 03 2012In this article we analyze the geodesics of test particles and light in the five dimensional (charged) doubly spinning black ring spacetime. Apparently it is not possible to separate the Hamilton-Jacobi-equation for (charged) doubly spinning black rings ... More

Geometry of Spinning Ellis WormholesAug 18 2016We give a detailed account of the properties of spinning Ellis wormholes, supported by a phantom field. The general set of solutions depends on three parameters, associated with the size of the throat, the rotation and the symmetry of the solutions. For ... More

Orbits in the Field of a Gravitating Magnetic MonopoleAug 13 2007Orbits of test particles and light rays are an important tool to study the properties of space-time metrics. Here we systematically study the properties of the gravitational field of a globally regular magnetic monopole in terms of the geodesics of test ... More