A Three-Generation Calabi-Yau Manifold with Small Hodge Numbers (2009)
Braun, Volker, Candelas, Philip, Davies, Rhys
We present a complete intersection Calabi-Yau manifold Y that has Euler number -72 and which admits free actions by two groups of automorphisms of order 12. These are the cyclic group Z_12 and the...
Three Generations on the Quintic Quotient (2009)
A three-generation SU(5) GUT, that is 3x(10+5bar) and a single 5-5bar pair, is constructed by compactification of the E_8 heterotic string. The base manifold is the Z_5 x Z_5-quotient of the quintic,...
GUTs in Type IIB Orientifold Compactifications (2008)
Blumenhagen, Ralph, Braun, Volker, Grimm, Thomas W., Weigand, Timo
We systematically analyse globally consistent SU(5) GUT models on intersecting D7-branes in genuine Calabi-Yau orientifolds with O3- and O7-planes. Beyond the well-known tadpole and K-theory...
Two Higgs Pair Heterotic Vacua and Flavor-Changing Neutral Currents (2008)
Ambroso, Michael, Braun, Volker, Ovrut, Burt A.
We present a vacuum of heterotic M-theory whose observable sector has the MSSM spectrum with the addition of one extra pair of Higgs-Higgs conjugate superfields. The quarks/leptons have a realistic...
Eigenvalues and Eigenfunctions of the Scalar Laplace Operator on Calabi-Yau Manifolds (2008)
Braun, Volker, Brelidze, Tamaz, Douglas, Michael R., Ovrut, Burt A.
A numerical algorithm for explicitly computing the spectrum of the Laplace-Beltrami operator on Calabi-Yau threefolds is presented. The requisite Ricci-flat metrics are calculated using a method...
Worldsheet Instantons and Torsion Curves (2008)
Braun, Volker, Kreuzer, Maximilian, Ovrut, Burt A., Scheidegger, Emanuel
We study aspects of worldsheet instantons relevant to a heterotic standard model. The non-simply connected Calabi-Yau threefold used admits Z_3 x Z_3 Wilson lines, and a more detailed investigation...
Worldsheet Instantons and Torsion Curves (2008)
Braun, Volker, Kreuzer, Maximilian, Ovrut, Burt, Scheidegger, Emanuel
We study aspects of worldsheet instantons relevant to a heterotic standard model. The non-simply connected Calabi-Yau threefold used admits Z_3 x Z_3 Wilson lines, and a more detailed investigation...
Calabi-Yau Metrics for Quotients and Complete Intersections (2007)
Braun, Volker, Brelidze, Tamaz, Douglas, Michael R., Ovrut, Burt A.
We extend previous computations of Calabi-Yau metrics on projective hypersurfaces to free quotients, complete intersections, and free quotients of complete intersections. In particular, we construct...
Siemens AG y Munich (Germany) (2007)
Volker Braun, Tiziana Margaria, Bernhard Ste
The paper reports on the use and impact of constraint-based veri cation and syn-thesis techniques in Siemens ' INXpress Advanced Service Design tool, an industrial product for the design of...
Immink, “An enumerative coding technique for dc-free runlength-limited sequences (2007)
Abstract—We present an enumerative technique for encoding and decoding dc-free runlength-limited sequences. This technique enables the encoding and decoding of sequences approaching the maxentropic...
Worldsheet Instantons and Torsion Curves, Part B: Mirror Symmetry (2007)
Braun, Volker, Kreuzer, Maximilian, Ovrut, Burt A., Scheidegger, Emanuel
We apply mirror symmetry to the problem of counting holomorphic rational curves in a Calabi-Yau threefold X with Z_3 x Z_3 Wilson lines. As we found in Part A [hep-th/0703182], the integral homology...
Worldsheet Instantons and Torsion Curves, Part A: Direct Computation (2007)
Braun, Volker, Kreuzer, Maximilian, Ovrut, Burt A., Scheidegger, Emanuel
As a first step towards studying vector bundle moduli in realistic heterotic compactifications, we identify all holomorphic rational curves in a Calabi-Yau threefold X with Z_3 x Z_3 Wilson lines....
Worldsheet Instantons, Torsion Curves, and Non-Perturbative Superpotentials (2007)
Braun, Volker, Kreuzer, Maximilian, Ovrut, Burt A., Scheidegger, Emanuel
As a first step towards computing instanton-generated superpotentials in heterotic standard model vacua, we determine the Gromov-Witten invariants for a Calabi-Yau threefold with fundamental group...
Towards Realizing Dynamical SUSY Breaking in Heterotic Model Building (2006)
Braun, Volker, Buchbinder, Evgeny I., Ovrut, Burt A.
We study a new mechanism to dynamically break supersymmetry in the E8xE8 heterotic string. As discussed recently in the literature, a long-lived, meta-stable non-supersymmetric vacuum can be achieved...
Dynamical SUSY Breaking in Heterotic M-Theory (2006)
Braun, Volker, Buchbinder, Evgeny I., Ovrut, Burt A.
It is shown that four-dimensional N=1 supersymmetric QCD with massive flavors in the fundamental representation of the gauge group can be realized in the hidden sector of E8xE8 heterotic string...
Stabilizing Moduli with a Positive Cosmological Constant in Heterotic M-Theory (2006)
It is shown that strongly coupled heterotic M-theory with anti-five-branes in the S^1/Z_2 bulk space can have meta-stable vacua which break N=1 supersymmetry and have a small, positive cosmological...
Stability of the Minimal Heterotic Standard Model Bundle (2006)
Braun, Volker, He, Yang-Hui, Ovrut, Burt A.
The observable sector of the "minimal heterotic standard model" has precisely the matter spectrum of the MSSM: three families of quarks and leptons, each with a right-handed neutrino, and one...
Yukawa Couplings in Heterotic Standard Models (2006)
Braun, Volker, He, Yang-Hui, Ovrut, Burt A.
In this paper, we present a formalism for computing the Yukawa couplings in heterotic standard models. This is accomplished by calculating the relevant triple products of cohomology groups, leading...
The Exact MSSM Spectrum from String Theory (2005)
Braun, Volker, He, Yang-Hui, Ovrut, Burt A., Pantev, Tony
We show the existence of realistic vacua in string theory whose observable sector has exactly the matter content of the MSSM. This is achieved by compactifying the E_8 x E_8 heterotic superstring on...
D-Brane Charges in Gepner Models (2005)
Braun, Volker, Schafer-Nameki, Sakura
We construct Gepner models in terms of coset conformal field theories and compute their twisted equivariant K-theories. These classify the D-brane charges on the associated geometric backgrounds and...
Moduli Dependent mu-Terms in a Heterotic Standard Model (2005)
Braun, Volker, He, Yang-Hui, Ovrut, Burt A., Pantev, Tony
In this paper, we present a formalism for computing the non-vanishing Higgs mu-terms in a heterotic standard model. This is accomplished by calculating the cubic product of the cohomology groups...
Heterotic Standard Model Moduli (2005)
Braun, Volker, He, Yang-Hui, Ovrut, Burt A., Pantev, Tony
In previous papers, we introduced a heterotic standard model and discussed its basic properties. The Calabi-Yau threefold has, generically, three Kahler and three complex structure moduli. The...
...
Vector Bundle Extensions, Sheaf Cohomology, and the Heterotic Standard Model (2005)
Braun, Volker, He, Yang-Hui, Ovrut, Burt A., Pantev, Tony
Stable, holomorphic vector bundles are constructed on an torus fibered, non-simply connected Calabi-Yau threefold using the method of bundle extensions. Since the manifold is multiply connected, we...
A Standard Model from the E8 x E8 Heterotic Superstring (2005)
Braun, Volker, He, Yang-Hui, Ovrut, Burt A., Pantev, Tony
In a previous paper, we introduced a heterotic standard model and discussed its basic properties. This vacuum has the spectrum of the MSSM with one additional pair of Higgs-Higgs conjugate fields and...
A Heterotic Standard Model (2005)
Braun, Volker, He, Yang-Hui, Ovrut, Burt A., Pantev, Tony
Within the context of the E_8 x E_8 heterotic superstring compactified on a smooth Calabi-Yau threefold with an SU(4) gauge instanton, we show the existence of simple, realistic N=1 supersymmetric...
...
Elliptic Calabi-Yau Threefolds with Z_3 x Z_3 Wilson Lines (2004)
Braun, Volker, Ovrut, Burt A., Pantev, Tony, Reinbacher, Rene
A torus fibered Calabi-Yau threefold with first homotopy group Z_3 x Z_3 is constructed as a free quotient of a fiber product of two dP_9 surfaces. Calabi-Yau threefolds of this type admit Z_3 x Z_3...
Gegenstand der vorliegenden Arbeit sind Leit- und Orientierungssysteme in Bibliotheken.Der Schwerpunkt liegt dabei auf öffentlichen Bibliotheken. Der theoretischeTeil soll klären, welche Aspekte zu...
Supersymmetric WZW models and twisted K-theory of SO(3) (2004)
Braun, Volker, Schafer-Nameki, Sakura
We present an encompassing treatment of D-brane charges in supersymmetric SO(3) WZW models. There are two distinct supersymmetric CFTs at each even level: the standard bosonic SO(3) modular invariant...
Heidelberg, Univ., Diss., 2005.
Analyse, Vergleich und Simulation der embryonalen Zellstammlinien verschiedener Nematoden (2003)
...
Twisted K-Theory of Lie Groups (2003)
I determine the twisted K-theory of all compact simply connected simple Lie groups. The computation reduces via the Freed-Hopkins-Teleman theorem to the CFT prescription, and thus explains why it...
...
Analyse, Vergleich und Simulation der embryonalen Zellstammlinien verschiedener Nematoden / (2003)
Heidelberg, Univ., Diss., 2003.
Analyse, Vergleich und Simulation der embryonalen Zellstammlinien verschiedener Nematoden (2003)
...
On Berenstein-Douglas-Seiberg Duality (2002)
I review the proposal of Berenstein-Douglas for a completely general definition of Seiberg duality. To give evidence for their conjecture I present the first example of a physical dual pair and...
The Standard Model on the Quintic (2002)
Blumenhagen, Ralph, Braun, Volker, Kors, Boris, Lust, Dieter
We describe the general geometrical framework of brane world constructions in orientifolds of type IIA string theory with D6-branes wrapping 3-cycles in a Calabi-Yau 3-fold, and point out their...
Orientifolds of K3 and Calabi-Yau Manifolds with Intersecting D-branes (2002)
Blumenhagen, Ralph, Braun, Volker, Kors, Boris, Lust, Dieter
We investigate orientifolds of type II string theory on K3 and Calabi-Yau 3-folds with intersecting D-branes wrapping special Lagrangian cycles. We determine quite generically the chiral massless...
Today's software development is mainly performed by IT experts. The application expert participates only in a light way in the software development process: traditionally, he is only involved within...
Orientifolds and Ktheory (2002)
Braun,Volker, Stefanski,Bogdan
Recently it has been shown that D-branes in orientifolds are not always described by equivariant Real Ktheory. In this paper we define a previously unstudied twisted version of equivariant Real...
Orientifolds and Ktheory (2002)
Braun, Volker, Stefanski, Bogdan
Recently it has been shown that D-branes in orientifolds are not always described by equivariant Real Ktheory. In this paper we define a previously unstudied twisted version of equivariant Real...
...
Superconformal Field Theories for Compact Manifolds with Spin(7) Holonomy (2001)
Blumenhagen, Ralph, Braun, Volker
We present a construction of superconformal field theories for manifolds with Spin(7) holonomy. Geometrically these models correspond to the realization of Spin(7) manifolds as anti-holomorphic...
Superconformal Field Theories for Compact G_2 Manifolds (2001)
Blumenhagen, Ralph, Braun, Volker
We present the construction of exactly solvable superconformal field theories describing Type II string models compactified on compact G_2 manifolds. These models are defined by anti-holomorphic...
Heidelberg, Univ., Diss., 2002.
Bound States of D(2p)-D0 Systems and Supersymmetric p-Cycles (2000)
Blumenhagen, Ralph, Braun, Volker, Helling, Robert
We discuss some issues related to D(2p)-D0 branes with background magnetic fluxes respectively, in a T-dual picture, Dp-Dp branes at angles. In particular, we describe the nature of the...
The Chern isomorphism determines the free part of the K-groups from ordinary cohomology. Thus to really understand the implications of K-theory for physics one must look at manifolds with K-torsion....
Münster (Westfalen), Univ., Diss., 1999.
M-theory compactification leads one to consider 7-manifolds obtained by rolling Calabi-Yau threefolds in the web of Calabi-Yau moduli spaces. The resulting 7-space in general has singularities...
Cool: A Control-flow Generator for System Analysis (1998)
Volker Braun, Jens Knoop, Dirk Koschützki
Cool is a unifying control-flow analysis (CFA) generator for system analysis, which is implemented within the METAFrame system [17]. It uniformly supports the automatic generation of transition...
On modulation, coding and signal processing for optical and magnetic recording systems / (1997)
Zugl.: Essen, University, Diss.
Zugl.: Essen, Univ., Diss., 1997.
Graphs in METAFrame: The Unifying Power of Polymorphism (1997)
Volker Braun, Andreas Claßen, V. Braun, Carsten Friedrich, Achim Dannecker, ...
. We present a highly polymorphic tool for the construction, synthesis, structuring, manipulation, investigation, and (symbolic) execution of graphs. The flexibility of this tool, which mainly arises...
A constraintoriented service creation environment (1996)
Bernhard Ste En, Tiziana Margaria, Andreas Cla En, Volker Braun, Manfred Reitenspie
The challenge of this joint project was to design and implement anenvironment for the creation of advanced telephone services (Intelligent Network Services) on the basis of a library of basic service...
The METAFrame'95 Environment (1996)
Bernhard Steffen, Tiziana Margaria, Andreas Claßen, Volker Braun
programs whose implementation is supported by the automatic, library-based synthesis of linear compositions of modules. More complex control structures glueing the linear portions together must be...
Incremental Formalization: a Key to Industrial Success (1996)
Bernhard Steffen, Tiziana Margaria, Andreas Claßen, Volker Braun, Lehrstuhl Fur Programmiersysteme
views focus the development process, and support error correction. This approach provides an incremental use of formal methods: if no formal constraints are defined, our system behaves like standard...
Service Creation: Formal Verification and Abstract Views (1996)
Bernhard Steffen, Tiziana Margaria, Andreas Claßen, Volker Braun, Manfred Reitenspie, Helmut Wendler, ...
Views Bernhard Steffen, Tiziana Margaria, Andreas Claßen, Volker Braun Universitat Passau (Germany) Manfred Reitenspieß, Helmut Wendler SiemensNixdorf Informationssysteme AG y , Munich (Germany)...
Incremental Formalization (1996)
Bernhard Steffen, Tiziana Margaria, Andreas Claßen, Volker Braun
views focus the development process, and support error correction. This approach provides an incremental use of formal methods: if no formal constraints are defined, our system behaves like standard...
A Constraint-Oriented Service Creation Environment (1996)
Bernhard Steffen, Tiziana Margaria, Andreas Claßen, Volker Braun, Viola Kriete, Manfred Reitenspieß, ...
ion Concretization Modification Control Control Service Libraries Selection Figure 1: The Service Creation Process ffl The service provider is familiar with the specific customer needs and enters...
An Environment for the Creation of Intelligent Network Services (1996)
Bernhard Steffen, Tiziana Margaria, Andreas Claßen, Volker Braun, Lehrstuhl Fur Programmiersysteme, Manfred Reitenspie
This paper presents a Service Creation Environment which is unique in offering global correctness and consistency checks. These guarantee frame conditions for the design concerning implementability,...
A Constraint-Oriented Service Creation Environment (1996)
Bernhard Steffen, Tiziana Margaria, Andreas Claßen, Volker Braun, Manfred Reitenspieß, Siemens Nixdorf, ...
The challenge of this joint project was to design and implement an environment for the creation of advanced telephone services (Intelligent Network Services) on the basis of a library of basic...
Incremental Formalization: a Key to Industrial Success (1995)
Bernhard Steffen, Tiziana Margaria, Andreas Claßen, Volker Braun, Lehrstuhl Fur Programmiersysteme
Views . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 9.2 Formal Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 10 Conclusions, Experience and...
An Environment for the Creation of Intelligent Network Services (1995)
Bernhard Steffen, Tiziana Margaria, Volker Braun, Manfred Reitenspie, Siemens Nixdorf, Informationssysteme Ag
This paper presents a Service Creation Environment which is unique in offering global correctness and consistency checks. These guarantee frame conditions for the design concerning implementability,...
Greifswald, Univ., Diss. A, 1988 (Nicht f.d. Austausch).
Thesis (doctoral)--Rheinische Friedrich-Wilhelms-Universität zu Bonn, 1974.
GUTs in Type IIB Orientifold Compactifications
Blumenhagen, Ralph, Braun, Volker, Grimm, Thomas W., Weigand, Timo
We systematically analyse globally consistent SU(5) GUT models on intersecting D7-branes in genuine Calabi-Yau orientifolds with O3- and O7-planes. Beyond the well-known tadpole and K-theory...