@article{Stephan2009, author = {Stephan, Christoph A.}, title = {Inverse seesaw mechanism in noncommutative geometry}, issn = {1550-7998}, doi = {10.1103/Physrevd.80.065007}, year = {2009}, abstract = {In this paper we will implement the inverse seesaw mechanism into the noncommutative framework on the basis of the AC extension of the standard model. The main difference from the classical AC model is the chiral nature of the AC fermions with respect to a U(1)(X) extension of the standard model gauge group. It is this extension which allows us to couple the right-handed neutrinos via a gauge invariant mass term to left-handed A particles. The natural scale of these gauge invariant masses is of the order of 10(17) GeV while the Dirac masses of the neutrino and the AC particles are generated dynamically and are therefore much smaller (similar to 1 to similar to 10(6) GeV). From this configuration, a working inverse seesaw mechanism for the neutrinos is obtained.}, language = {en} } @article{Stephan2009, author = {Stephan, Christoph A.}, title = {Krajewski diagrams and the standard model}, issn = {0022-2488}, doi = {10.1063/1.3112622}, year = {2009}, abstract = {This paper provides a complete list of Krajewski diagrams representing the standard model of particle physics. We will give the possible representations of the algebra and the anomaly free lifts which provide the representation of the standard model gauge group on the fermionic Hilbert space. The algebra representations following from the Krajewski diagrams are not complete in the sense that the corresponding spectral triples do not necessarily obey to the axiom of Poincare duality. This defect may be repaired by adding new particles to the model, i.e., by building models beyond the standard model. The aim of this list of finite spectral triples (up to Poincare duality) is therefore to provide a basis for model building beyond the standard model.}, language = {en} } @article{Stephan2009, author = {Stephan, Christoph A.}, title = {New scalar fields in noncommutative geometry}, issn = {1550-7998}, doi = {10.1103/Physrevd.79.065013}, year = {2009}, abstract = {In this publication we present an extension of the standard model within the framework of Connes' noncommutative geometry. The model presented here is based on a minimal spectral triple which contains the standard model particles, new vectorlike fermions, and a new U(1) gauge subgroup. Additionally a new complex scalar field appears that couples to the right-handed neutrino, the new fermions, and the standard Higgs particle. The bosonic part of the action is given by the spectral action which also determines relations among the gauge couplings, the quartic scalar couplings, and the Yukawa couplings at a cutoff energy of similar to 10(17) GeV. We investigate the renormalization group flow of these relations. The low energy behavior allows to constrain the Higgs mass, the mass of the new scalar, and the mixing between these two scalar fields.}, language = {en} } @article{Stephan2014, author = {Stephan, Christoph A.}, title = {A dark sector extension of the almost-commutative standard model}, series = {International journal of modern physics : A, Particles and fields, gravitation, cosmology, nuclear physics}, volume = {29}, journal = {International journal of modern physics : A, Particles and fields, gravitation, cosmology, nuclear physics}, number = {1}, publisher = {World Scientific}, address = {Singapore}, issn = {0217-751X}, doi = {10.1142/S0217751X14500055}, pages = {30}, year = {2014}, abstract = {We consider an extension of the Standard Model within the framework of Noncommutative Geometry. The model is based on an older model [C. A. Stephan, Phys. Rev. D 79, 065013 (2009)] which extends the Standard Model by new fermions, a new U(1)-gauge group and, crucially, a new scalar field which couples to the Higgs field. This new scalar field allows to lower the mass of the Higgs mass from similar to 170 GeV, as predicted by the Spectral Action for the Standard Model, to a value of 120-130 GeV. The shortcoming of the previous model lay in its inability to meet all the constraints on the gauge couplings implied by the Spectral Action. These shortcomings are cured in the present model which also features a "dark sector" containing fermions and scalar particles.}, language = {en} } @article{ReadKegelKluteetal.2013, author = {Read, Betsy A. and Kegel, Jessica and Klute, Mary J. and Kuo, Alan and Lefebvre, Stephane C. and Maumus, Florian and Mayer, Christoph and Miller, John and Monier, Adam and Salamov, Asaf and Young, Jeremy and Aguilar, Maria and Claverie, Jean-Michel and Frickenhaus, Stephan and Gonzalez, Karina and Herman, Emily K. and Lin, Yao-Cheng and Napier, Johnathan and Ogata, Hiroyuki and Sarno, Analissa F. and Shmutz, Jeremy and Schroeder, Declan and de Vargas, Colomban and Verret, Frederic and von Dassow, Peter and Valentin, Klaus and Van de Peer, Yves and Wheeler, Glen and Dacks, Joel B. and Delwiche, Charles F. and Dyhrman, Sonya T. and Gl{\"o}ckner, Gernot and John, Uwe and Richards, Thomas and Worden, Alexandra Z. and Zhang, Xiaoyu and Grigoriev, Igor V. and Allen, Andrew E. and Bidle, Kay and Borodovsky, M. and Bowler, C. and Brownlee, Colin and Cock, J. Mark and Elias, Marek and Gladyshev, Vadim N. and Groth, Marco and Guda, Chittibabu and Hadaegh, Ahmad and Iglesias-Rodriguez, Maria Debora and Jenkins, J. and Jones, Bethan M. and Lawson, Tracy and Leese, Florian and Lindquist, Erika and Lobanov, Alexei and Lomsadze, Alexandre and Malik, Shehre-Banoo and Marsh, Mary E. and Mackinder, Luke and Mock, Thomas and M{\"u}ller-R{\"o}ber, Bernd and Pagarete, Antonio and Parker, Micaela and Probert, Ian and Quesneville, Hadi and Raines, Christine and Rensing, Stefan A. and Riano-Pachon, Diego Mauricio and Richier, Sophie and Rokitta, Sebastian and Shiraiwa, Yoshihiro and Soanes, Darren M. and van der Giezen, Mark and Wahlund, Thomas M. and Williams, Bryony and Wilson, Willie and Wolfe, Gordon and Wurch, Louie L.}, title = {Pan genome of the phytoplankton Emiliania underpins its global distribution}, series = {Nature : the international weekly journal of science}, volume = {499}, journal = {Nature : the international weekly journal of science}, number = {7457}, publisher = {Nature Publ. Group}, address = {London}, organization = {Emiliania Huxleyi Annotation}, issn = {0028-0836}, doi = {10.1038/nature12221}, pages = {209 -- 213}, year = {2013}, abstract = {Coccolithophores have influenced the global climate for over 200 million years(1). These marine phytoplankton can account for 20 per cent of total carbon fixation in some systems(2). They form blooms that can occupy hundreds of thousands of square kilometres and are distinguished by their elegantly sculpted calcium carbonate exoskeletons (coccoliths), rendering them visible from space(3). Although coccolithophores export carbon in the form of organic matter and calcite to the sea floor, they also release CO2 in the calcification process. Hence, they have a complex influence on the carbon cycle, driving either CO2 production or uptake, sequestration and export to the deep ocean(4). Here we report the first haptophyte reference genome, from the coccolithophore Emiliania huxleyi strain CCMP1516, and sequences from 13 additional isolates. Our analyses reveal a pan genome (core genes plus genes distributed variably between strains) probably supported by an atypical complement of repetitive sequence in the genome. Comparisons across strains demonstrate that E. huxleyi, which has long been considered a single species, harbours extensive genome variability reflected in different metabolic repertoires. Genome variability within this species complex seems to underpin its capacity both to thrive in habitats ranging from the equator to the subarctic and to form large-scale episodic blooms under a wide variety of environmental conditions.}, language = {en} } @book{RascheRehder2017, author = {Rasche, Christoph and Rehder, Stephan A.}, title = {Internationales Management}, series = {Kohlhammer executive education}, journal = {Kohlhammer executive education}, editor = {Wagner, Dieter and M{\"u}lller, Magnus and Madani, Roya}, publisher = {Kohlhammer}, address = {Stuttgart}, isbn = {978-3-17-033399-4}, publisher = {Universit{\"a}t Potsdam}, pages = {101}, year = {2017}, language = {de} } @article{PfaeffleStephan2013, author = {Pf{\"a}ffle, Frank and Stephan, Christoph A.}, title = {Chiral asymmetry and the spectral action}, series = {Communications in mathematical physics}, volume = {321}, journal = {Communications in mathematical physics}, number = {2}, publisher = {Springer}, address = {New York}, issn = {0010-3616}, doi = {10.1007/s00220-012-1641-6}, pages = {283 -- 310}, year = {2013}, abstract = {We consider orthogonal connections with arbitrary torsion on compact Riemannian manifolds. For the induced Dirac operators, twisted Dirac operators and Dirac operators of Chamseddine-Connes type we compute the spectral action. In addition to the Einstein-Hilbert action and the bosonic part of the Standard Model Lagrangian we find the Holst term from Loop Quantum Gravity, a coupling of the Holst term to the scalar curvature and a prediction for the value of the Barbero-Immirzi parameter.}, language = {en} } @article{PfaeffleStephan2012, author = {Pf{\"a}ffle, Frank and Stephan, Christoph A.}, title = {On gravity, torsion and the spectral action principle}, series = {Journal of functional analysis}, volume = {262}, journal = {Journal of functional analysis}, number = {4}, publisher = {Elsevier}, address = {San Diego}, issn = {0022-1236}, doi = {10.1016/j.jfa.2011.11.013}, pages = {1529 -- 1565}, year = {2012}, abstract = {We consider compact Riemannian spin manifolds without boundary equipped with orthogonal connections. We investigate the induced Dirac operators and the associated commutative spectral triples. In case of dimension four and totally anti-symmetric torsion we compute the Chamseddine-Connes spectral action, deduce the equations of motions and discuss critical points.}, language = {en} } @article{PfaeffleStephan2011, author = {Pf{\"a}ffle, Frank and Stephan, Christoph A.}, title = {The holst action by the spectral action principle}, series = {Communications in mathematical physics}, volume = {307}, journal = {Communications in mathematical physics}, number = {1}, publisher = {Springer}, address = {New York}, issn = {0010-3616}, doi = {10.1007/s00220-011-1303-0}, pages = {261 -- 273}, year = {2011}, abstract = {We investigate the Holst action for closed Riemannian 4-manifolds with orthogonal connections. For connections whose torsion has zero Cartan type component we show that the Holst action can be recovered from the heat asymptotics for the natural Dirac operator acting on left-handed spinor fields.}, language = {en} } @misc{PfaeffleStephan2012, author = {Pf{\"a}ffle, Frank and Stephan, Christoph A.}, title = {The holst action by the spectral action principle (vol 307, pg 261, 2011)}, series = {Communications in mathematical physics}, volume = {313}, journal = {Communications in mathematical physics}, number = {1}, publisher = {Springer}, address = {New York}, issn = {0010-3616}, doi = {10.1007/s00220-012-1507-y}, pages = {291 -- 292}, year = {2012}, language = {en} }