Publications (90)
The action of outer automorphisms on bundles of chiral blocks
J. Fuchs, C. Schweigert
On the bundles of WZW chiral blocks over the moduli space of a punctured rational curve we construct isomorphisms that implement the action of outer automorphisms of the underlying…
PLATOSpec: a precise spectrograph in support of space missions
P. Kabáth, M. Skarka, A. Hatzes +42
The upcoming space missions that will characterize exoplanets, such as PLATO and Ariel, will collect huge amounts of data that will need to be complemented with ground-based observ…
Laboratory unravelling of matter accretion in young stars
G. Revet, S. N. Chen, R. Bonito +22
Accretion dynamics in the forming of young stars is still object of debate because of limitations in observations and modelling. Through scaled laboratory experiments of collimated…
Branes: from free fields to general backgrounds
J. Fuchs, C. Schweigert
Motivated by recent developments in string theory, we study the structure of boundary conditions in arbitrary conformal field theories. A boundary condition is specified by two typ…
Experimental investigation of the effect of ionization on the 51V(p,n)51Cr reaction
V. Lelasseux, P. -A. Söderström, S. Aogaki +15
The investigation of the effects of average atomic ionization on nuclear reactions is of prime importance for nuclear astrophysics. No direct experimental measurement using a plasm…
Inferring possible magnetic field strength of accreting inflows in EXor-type objects from scaled laboratory experiments
K. Burdonov, R. Bonito, T. Giannini +28
Aims. EXor-type objects are protostars that display powerful UV-optical outbursts caused by intermittent and powerful events of magnetospheric accretion. These objects are not yet…
Evidence of resonant surface wave excitation in the relativistic regime through measurements of proton acceleration from grating targets
T. Ceccotti, V. Floquet, A. Sgattoni +25
The interaction of laser pulses with thin grating targets, having a periodic groove at the irradiated surface, has been experimentally investigated. Ultrahigh contrast ($\sim 10^{1…
Laser Driven Nuclear physics at ELINP
F. Negoita, M. Roth, P. G. Thirolf +53
High power lasers have proven being capable to produce high energy gamma rays, charged particles and neutrons to induce all kinds of nuclear reactions. At ELI, the studies with hig…
Dynamics of self-generated, large amplitude magnetic fields following high-intensity laser matter interaction
G. Sarri, A. Macchi, C. A. Cecchetti +15
The dynamics of magnetic fields with amplitude of several tens of Megagauss, generated at both sides of a solid target irradiated with a high intensity (? 1019W/cm2) picosecond las…
Lectures on conformal field theory and Kac-Moody algebras
J. Fuchs
This is an introduction to the basic ideas and to a few further selected topics in conformal quantum field theory and in the theory of Kac-Moody algebras.
Investigation of Laser Plasma Instabilities driven by Coupled High-Power Laser Beams in Magnetized Underdense Plasmas
C. L. C. Lacoste, D. Oportus, J. Béard +10
Stimulated Brillouin and Raman scattering (SBS and SRS) are instabilities that affect the propagation of high-power lasers in plasmas. The latter is further affected by Cross-Talk…
Molecular Bose-Einstein condensation in a versatile low power crossed dipole trap
J. Fuchs, G. J. Duffy, G. Veeravalli +5
We produce Bose-Einstein condensates of 6Li2 molecules in a low power (22 W) crossed optical dipole trap. Fermionic 6Li atoms are collected in a magneto-optical trap from a Zeeman…
Anomalous Self-Generated Electrostatic Fields in Nanosecond Laser-Plasma Interaction
L. Lancia, M. Grech, S. Weber +15
Electrostatic (E) fields associated with the interaction of a well-controlled, high-power, nanosecond laser pulse with an underdense plasma are diagnosed by proton radiography. Usi…
Calibration of Time Of Flight Detectors Using Laser-driven Neutron Source
S. R. Mirfayzi, S. Kar, H. Ahmed +17
Calibration of three scintillators (EJ232Q, BC422Q and EJ410) in a time-of-flight (TOF) arrangement using a laser drive-neutron source is presented. The three plastic scintillator…
Saturation of the compression of two interacting magnetic flux tubes evidenced in the laboratory
A. Sladkov, C. Fegan, W. Yao +16
Interactions between magnetic fields advected by matter play a fundamental role in the Universe at a diverse range of scales. A crucial role these interactions play is in making tu…
Collimated protons accelerated from an overdense gas jet irradiated by a 1 micron wavelength high-intensity short-pulse laser
S. N. Chen, M. Vranic, T. Gangolf +13
We have investigated proton acceleration in the forward direction from a near-critical density hydrogen gas jet target irradiated by a high intensity (10^18 W/cm^2), short-pulse (5…
Laboratory evidence for proton energization by collisionless shock surfing
W. Yao, A. Fazzini, S. N. Chen +19
Charged particles can be accelerated to high energies by collisionless shock waves in astrophysical environments, such as supernova remnants. By interacting with the magnetized amb…
Particle energization in colliding subcritical collisionless shocks investigated in the laboratory
A. Fazzini, W. Yao, K. Burdonov +16
Colliding collisionless shocks appear in a great variety of astrophysical phenomena and are thought to be possible sources of particle acceleration in the Universe. To investigate…
Fusion rules in conformal field theory
J. Fuchs
Several aspects of fusion rings and fusion rule algebras, and of their manifestations in twodimensional (conformal) field theory, are described: diagonalization and the connection…
Laboratory disruption of scaled astrophysical outflows by a misaligned magnetic field
G. Revet, B. Khiar, E. Filippov +20
The shaping of astrophysical outflows into bright, dense and collimated jets due to magnetic pressure is here investigated using laboratory experiments. We notably look at the impa…
Projections in string theory and boundary states for Gepner models
J. Fuchs, C. Schweigert, J. Walcher
In string theory various projections have to be imposed to ensure supersymmetry. We study the consequences of these projections in the presence of world sheet boundaries. A-type bo…
Symmetry breaking boundaries I. General theory
J. Fuchs, C. Schweigert
We study conformally invariant boundary conditions that break part of the bulk symmetries. A general theory is developped for those boundary conditions for which the preserved suba…
The geometry of WZW branes
G. Felder, J. Fröhlich, J. Fuchs +1
The structures in target space geometry that correspond to conformally invariant boundary conditions in WZW theories are determined both by studying the scattering of closed string…
Gaia Data Release 1: The variability processing & analysis and its application to the south ecliptic pole region
L. Eyer, N. Mowlavi, D. W. Evans +70
The ESA Gaia mission provides a unique time-domain survey for more than one billion sources brighter than G=20.7 mag. Gaia offers the unprecedented opportunity to study variability…
S_4-symmetry of 6j-symbols and Frobenius-Schur indicators in rigid monoidal C^*-categories
J. Fuchs, A. Ch. Ganchev, K. Szlachanyi +1
We show that a left-rigid monoidal C^*-category with irreducible monoidal unit is also a sovereign and spherical category. Defining a Frobenius-Schur type indicator we obtain selec…
Fixed point resolution in conformal field theory
J. Fuchs, A. N. Schellekens, C. Schweigert
We summarize recent progress in the understanding of fixed point resolution for conformal field theories. Fixed points in both coset conformal field theories and non-diagonal modul…
Dynamics of nanosecond laser pulse propagation and of associated instabilities in a magnetized underdense plasma
W. Yao, A. Higginson, J. -R. Marquès +19
The propagation and energy coupling of intense laser beams in plasmas are critical issues in laser-driven inertial confinement fusion. Applying magnetic fields to such a setup has…
Nonsemisimple Fusion Algebras and the Verlinde Formula
J. Fuchs, S. Hwang, A. M. Semikhatov +1
We find a nonsemisimple fusion algebra F_p associated with each (1,p) Virasoro model. We present a nonsemisimple generalization of the Verlinde formula which allows us to derive F_…
Bundles of chiral blocks and boundary conditions in CFT
J. Fuchs, C. Schweigert
Various aspects of spaces of chiral blocks are discussed. In particular, conjectures about the dimensions of irreducible sub-bundles are reviewed and their relation to symmetry bre…
Experimental mitigation of fast magnetic reconnection in multiple interacting laser-produced plasmas
S. Bolaños, R. Smets, C. Courtois +11
The meeting of astrophysical plasmas and their magnetic fields creates many reconnection sites. We experimentally compare the reconnection rate of laser-driven magnetic reconnectio…
Boundary Fixed Points, Enhanced Gauge Symmetry and Singular Bundles on K3
J. Fuchs, P. Kaste, W. Lerche +3
We investigate certain fixed points in the boundary conformal field theory representation of type IIA D-branes on Gepner points of K3. They correspond geometrically to degenerate b…
Completeness of boundary conditions for the critical three-state Potts model
J. Fuchs, C. Schweigert
We show that the conformally invariant boundary conditions for the three-state Potts model are exhausted by the eight known solutions. Their structure is seen to be similar to the…
Detailed characterization of laboratory magnetized super-critical collisionless shock and of the associated proton energization
W. Yao, A. Fazzini, S. N. Chen +19
Collisionless shocks are ubiquitous in the Universe and are held responsible for the production of non-thermal particles and high-energy radiation. In the absence of particle colli…
Laboratory evidence of the halting of magnetic reconnection by a weak guide field
S. Bolanos, R. Smets, S. N. Chen +10
Magnetic reconnection occurs when two plasmas having co-planar but anti-parallel magnetic fields meet. At the contact point, the field is locally annihilated and the magnetic energ…
Gaia Data Release 1. Testing the parallaxes with local Cepheids and RR Lyrae stars
Gaia Collaboration, G. Clementini, L. Eyer +588
Parallaxes for 331 classical Cepheids, 31 Type II Cepheids and 364 RR Lyrae stars in common between Gaia and the Hipparcos and Tycho-2 catalogues are published in Gaia Data Release…
Data on 824 fireballs observed by the digital cameras of the European Fireball Network in 2017-2018. I. Description of the network, data reduction procedures, and the catalog
J. Borovicka, P. Spurny, L. Shrbeny +10
A catalog of 824 fireballs (bright meteors), observed by a dedicated network of all-sky digital photographic cameras in central Europe in the years 2017-2018 is presented. The stat…
Weibel-mediated filamentary structures observed in the ICF context
C. Ruyer, S. Bolaños, P. E. Masson Laborde +16
In light of novel and past experimental results, we demonstrate how Weibel-mediated filamentary structures can develop in the expanding plasma plume of a laser-irradiated foil. The…
Linear dichroic soft X-ray microscopy of ferroelectric stripe domains in epitaxial KNaNbO
M. Schneider, T. A. Butcher, S. Wagner +19
Functional properties of ferroelectric thin films are governed by domains that can be engineered by epitaxial strain. Soft X-ray microscopy can image domain structures with element…
Electromagnetically Induced Transparency in 6Li
J. Fuchs, G. J. Duffy, W. J. Rowlands +1
We report electromagnetically induced transparency for the D1 and D2 lines in Li in both a vapour cell and an atomic beam. Electromagnetically induced transparency is created…
Local Persistence in the Directed Percolation Universality Class
J. Fuchs, J. Schelter, F. Ginelli +1
We revisit the problem of local persistence in directed percolation, reporting improved estimates of the persistence exponent in 1+1 dimensions, discovering strong corrections to s…
Symmetry breaking boundary conditions and WZW orbifolds
L. Birke, J. Fuchs, C. Schweigert
Symmetry breaking boundary conditions for WZW theories are discussed. We derive explicit formulae for the reflection coefficients in the presence of boundary conditions that preser…
Conformal boundary conditions and 3D topological field theory
J. Fuchs, I. Runkel, C. Schweigert
Topological field theory in three dimensions provides a powerful tool to construct correlation functions and to describe boundary conditions in two-dimensional conformal field theo…
The singularity structure of the Yang-Mills configuration space
J. Fuchs
The geometric description of Yang-Mills theories and their configuration space M is reviewed. The presence of singularities in M is explained and some of their properties are descr…
Laboratory evidence of electron pressure anisotropy driving plasmoid mediated magnetic reconnection
A. Sladkov, T. Waltenspiel, H. Ahmed +8
Plasmoid-driven magnetic reconnection in elongated current sheets is suspected to be an ubiquitous phenomenon in space and astrophysical plasmas, but the mechanisms driving its ons…
Enhanced x-ray emission arising from laser-plasma confinement by a strong transverse magnetic field
E. D. Filippov, S. S. Makarov, K. F. Burdonov +13
We analyze, using experiments and 3D MHD numerical simulations, the dynamics and radiative properties of a plasma ablated by a laser (1 ns, 10-10 W/cm) from a sol…
Level-Rank Duality of WZW Theories and Isomorphisms of N=2 Coset Models
J. Fuchs, C. Schweigert
Mappings between certain infinite series of N=2 superconformal coset models are constructed. They make use of level-rank dualities for B, C and D type theories. While the WZW level…
Efficient ion re-acceleration in laboratory-produced interpenetrating collisionless shocks
W. Yao, I. Cohen, P. Suarez Gerona +20
Although the origin of cosmic rays (CRs) remains an open question, collisionless magnetized shock waves are widely regarded as key sites for particle acceleration. Recent theories…
Conformal Correlation Functions, Frobenius Algebras and Triangulations
J. Fuchs, I. Runkel, C. Schweigert
We formulate two-dimensional rational conformal field theory as a natural generalization of two-dimensional lattice topological field theory. To this end we lift various structures…
On the quantum symmetry of rational field theories
J. Fuchs, A. Ganchev, P. Vecsernyes
We describe the role of Rational Hopf Algebras as the symmetries of rational field theories and discuss their relation with algebraic field theory, braided monoidal categories and…
Simultaneous PW-scale laser driven MeV X-ray and neutron beam characterization for dual radiography capability
I. Cohen, W. Yao, N. Mirkovic +28
Laser-driven, high-brilliance secondary sources (electrons, ions, neutrons, X-rays) open new perspectives for compact material probing and imaging of high-speed events. A key advan…
Acceleration of collimated 45 MeV protons by collisionless shocks driven in low-density, large-scale gradient plasmas by a 10^20 W/cm^2, 1 micron wavelength laser
P. Antici, E. Boella, S. N. Chen +17
A new type of proton acceleration stemming from large-scale gradients, low-density targets, irradiated by an intense near-infrared laser is observed. The produced protons are chara…
Laser experiment for the study of accretion dynamics of Young Stellar Objects: design and scaling
G. Revet, B. Khiar, J. Béard +5
A new experimental set-up designed to investigate the accretion dynamics in newly born stars is presented. It takes advantage of a magnetically collimated stream produced by coupli…
Twining characters and orbit Lie algebras
J. Fuchs, U. Ray, A. N. Schellekens +1
We associate to outer automorphisms of generalized Kac-Moody algebras generalized character-valued indices, the twining characters. A character formula for twining characters is de…
D-brane conformal field theory
J. Fuchs, C. Schweigert
We outline the structure of boundary conditions in conformal field theory. A boundary condition is specified by a consistent collection of reflection coefficients for bulk fields o…
The world sheet revisited
C. Schweigert, J. Fuchs
We investigate the mathematical structure of the world sheet in two-dimensional conformal field theories.
Numerical investigation of spallation neutrons generated from petawatt-scale laser-driven proton beams
B. Martinez, S. N. Chen, S. Bolaños +15
Due to their high cost of acquisition and operation, there are still a limited number of high-yield, high-flux neutron source facilities worldwide. In this context, laser-driven ne…
Classifying algebras for boundary conditions and traces on spaces of conformal blocks
C. Schweigert, J. Fuchs
The boundary conditions of a non-trivial string background are classified. To this end we need traces on various spaces of conformal blocks, for which generalizations of the Verlin…
Characterization and performance of the Apollon Short-Focal-Area facility following its commissioning at 1 PW level
K. Burdonov, A. Fazzini, V. Lelasseux +45
We present the results of the first commissioning phase of the ``short focal length'' area (SFA) of the Apollon laser facility (located in Saclay, France), which was performed with…
Boundaries, crosscaps and simple currents
J. Fuchs, L. R. Huiszoon, A. N. Schellekens +2
Universal formulas for the boundary and crosscap coefficients are presented, which are valid for all symmetric simple current modifications of the charge conjugation invariant of a…
Quasi-Galois Symmetries of the Modular S-Matrix
J. Fuchs, A. N. Schellekens, C. Schweigert
The recently introduced Galois symmetries of RCFT are generalized, for the WZW case, to `quasi-Galois symmetries'. These symmetries can be used to derive a large number of equaliti…
A representation theoretic approach to the WZW Verlinde formula
J. Fuchs, C. Schweigert
By exploring the description of chiral blocks in terms of co-invariants, a derivation of the Verlinde formula for WZW models is obtained which is entirely based on the representati…
Experimental evidence for coronal mass ejection suppression in strong stellar magnetic fields
S. N. Chen, K. Burdonov, W. Yao +10
Solar coronal mass ejections (CME) are routinely observed, but as of yet there exist few convincing detections of stellar CMEs. A reason for this could be the stronger magnetic fie…
Symmetry breaking boundaries II. More structures; examples
J. Fuchs, C. Schweigert
Various structural properties of the space of symmetry breaking boundary conditions that preserve an orbifold subalgebra are established. To each such boundary condition we associa…
Lie algebra automorphisms in conformal field theory
J. Fuchs, C. Schweigert
The role of automorphisms of infinite-dimensional Lie algebras in conformal field theory is examined. Two main types of applications are discussed; they are related to the enhancem…
Laser-produced magnetic-Rayleigh-Taylor unstable plasma slabs in a 20 T magnetic field
B. Khiar, G. Revet, A. Ciardi +15
Magnetized laser-produced plasmas are central to many novel laboratory astrophysics and inertial confinement fusion studies, as well as in industrial applications. Here we provide…
Solitonic sectors, conformal boundary conditions and three-dimensional topological field theory
C. Schweigert, J. Fuchs
The correlation functions of a two-dimensional rational conformal field theory, for an arbitrary number of bulk and boundary fields and arbitrary world sheets can be expressed in t…
Calibration of the scintillation of cerium-doped yttrium aluminum garnet crystals irradiated by monoenergetic 4 MeV energy electrons
K. Burdonov, P. Forestier-Colleoni, J. -N. Cayla +8
This paper presents the results of measurements of fluorescing cerium-doped yttrium aluminum garnet crystals after being irradiated by an accelerated electron beam with energy of a…
Astrophysics of magnetically collimated jets generated from laser-produced plasmas
A. Ciardi, T. Vinci, J. Fuchs +4
The generation of astrophysically relevant jets, from magnetically collimated, laser-produced plasmas, is investigated through three-dimensional, magneto-hydrodynamic simulations.…
Investigating particle acceleration dynamics in interpenetrating magnetized collisionless super-critical shocks
W. Yao, A. Fazzini, S. N. Chen +9
Colliding collisionless shocks appear in a great variety of astrophysical phenomena and are thought to be possible sources of particle acceleration in the Universe. We have previou…
Pulsed magnetic field generation system for laser-plasma research
A. G. Luchinin, V. A. Malyshev, E. A. Kopelovich +10
An up to 15 T pulsed magnetic field generator in a volume of a few cubic centimeters has been created for experiments with magnetized laser plasma. The magnetic field is created by…
Binding Energies of 6Li p-wave Feshbach Molecules
J. Fuchs, C. Ticknor, P. Dyke +5
We present measurements of the binding energies of Li p-wave Feshbach molecules formed in combinations of the (F = 1/2, m_F = +1/2), (1), and (F = 1/2, m_F = -1/2), (2), states…
Solitonic sectors, alpha-induction and symmetry breaking boundaries
J. Fuchs, C. Schweigert
We develop a systematic approach to boundary conditions that break bulk symmetries in a general way such that left and right movers are not necessarily connected by an automorphism…
An online readout CMOS detector to measure ion spectra produced by high-repetition-rate high-power lasers
K. Burdonov, R. Lelievre, P. Forestier-Colleoni +5
We present the design and the absolute calibration of charged particle high-repetition-rate online readout CMOS system tailored for high-power laser experiments. This system equips…
Orbifold analysis of broken bulk symmetries
J. Fuchs, C. Schweigert
In two-dimensional conformal field theory, we analyze conformally invariant boundary conditions which break part of the bulk symmetries. When the subalgebra that is preserved by th…
Galois Modular Invariants of WZW Models
J. Fuchs, A. N. Schellekens, C. Schweigert
The set of modular invariants that can be obtained from Galois transformations is investigated systematically for WZW models. It is shown that a large subset of Galois modular inva…
Buffered spectrally-peaked proton beams in the relativistic-transparency regime
N. P. Dover, M. J. V. Streeter, C. A. J. Palmer +23
Spectrally-peaked proton beams ( MeV, MeV) have been observed from the interaction of an intense laser ( Wcm) with ultrathin CH fo…
Joule-level high effiency energy transfer to sub-picosecond laser pulses by a plasma-based amplifier
J. -R. Marquès, L. Lancia, T. Gangolf +9
Laser plasma amplification of sub-picosecond pulses above the Joule level is demonstrated, a major milestone for this scheme to become a solution for the next-generation of ultra-h…
Conformal boundary conditions and three-dimensional topological field theory
G. Felder, J. Fr"ohlich, J. Fuchs +1
We present a general construction of all correlation functions of a two-dimensional rational conformal field theory, for an arbitrary number of bulk and boundary fields and arbitra…
Category theory for conformal boundary conditions
J. Fuchs, C. Schweigert
We study properties of the category of modules of an algebra object A in a tensor category C. We show that the module category inherits various structures from C, provided that A i…
Global Characterization of a Laser-Generated Neutron Source
D. P. Higginson, R. Lelièvre, L. Vassura +17
Laser-driven neutron sources are routinely produced by the interaction of laser-accelerated protons with a converter. They present complementary characteristics to those of convent…
Universal simple current vertex operators
J. Fuchs
We construct a vertex operator realization for the simple current primary fields of WZW theories which are based on simply laced affine Lie algebras g. This is achieved by employin…
Logarithmic Conformal Field Theories via Logarithmic Deformations
J. Fjelstad, J. Fuchs, S. Hwang +2
We construct logarithmic conformal field theories starting from an ordinary conformal field theory -- with a chiral algebra C and the corresponding space of states V -- via a two-s…
Laboratory evidence for asymmetric accretion structure upon slanted matter impact in young stars
K. Burdonov, G. Revet, R. Bonito +15
Investigating in the laboratory the process of matter accretion onto forming stars through scaled experiments is important in order to better understand star and planetary systems…
Conformal field theory, boundary conditions and applications to string theory
C. Schweigert, J. Fuchs, J. Walcher
This is an introduction to two-dimensional conformal field theory and its applications in string theory. Modern concepts of conformal field theory are explained, and it is outlined…
CFT fusion rules, DHR gauge groups, and CAR algebras
J. B"ockenhauer, J. Fuchs
It is demonstrated that several series of conformal field theories, while satisfying braid group statistics, can still be described in the conventional setting of the DHR theory, i…
A classifying algebra for boundary conditions
J. Fuchs, C. Schweigert
We introduce a finite-dimensional algebra that controls the possible boundary conditions of a conformal field theory. For theories that are obtained by modding out a Z_2 symmetry (…
Plasma-wall interaction in laser inertial fusion reactors: novel proposals for radiation tests of first wall materials
J. Alvarez Ruiz, A. Rivera, K. Mima +8
Dry-wall laser inertial fusion (LIF) chambers will have to withstand strong bursts of fast charged particles which will deposit tens of kJ m and implant more than 10…
D-brane conformal field theory and bundles of conformal blocks
J. Fuchs, C. Schweigert
Conformal blocks form a system of vector bundles over the moduli space of complex curves with marked points. We discuss various aspects of these bundles. In particular, we present…
Gaia Data Release 1. Open cluster astrometry: performance, limitations, and future prospects
Gaia Collaboration, F. van Leeuwen, A. Vallenari +589
Context. The first Gaia Data Release contains the Tycho-Gaia Astrometric Solution (TGAS). This is a subset of about 2 million stars for which, besides the position and photometry,…
Characterisation of deuterium spectra from laser driven multi-species sources by employing differentially filtered image plate detectors in Thomson spectrometers
A. Alejo, S. Kar, H. Ahmed +23
A novel method for characterising the full spectrum of deuteron ions emitted by laser driven multi-species ion sources is discussed. The procedure is based on using differential fi…