Dr
Ulrik Uggerhøj
(Department of Physics and Astronomy, Aarhus University, Denmark)
09/07/2013, 09:05
Prof.
Nikolay Narozhny
(National Research Nuclear University MEPhI)
09/07/2013, 09:15
oral presentation
The development of laser technologies promises very rapid growth of laser intensities in close future already. Two exawatt class facilities (ELI and XCELS, Russia) in Europe are already in the planning stage. Realization of these projects will make available a laser of intensity ~10^26 W/cm^2 or even higher. Therefore discussion of nonlinear optical effects in vacuum are becoming urgent for...
Prof.
Carsten Mueller
(Institute of Theoretical Physics, Heinrich Heine University Duesseldorf)
09/07/2013, 10:00
oral presentation
Electron-positron pair production by an incident high-energy photon or a relativistic proton colliding with an intense laser field is considered. Our focus lies on the role played by the electron spin degree of freedom. A comparative study between production of Dirac versus Klein-Gordon pairs is performed [1,2] and a helicity analysis is carried out [3].
[1] S. Villalba-Chavez and C....
Dr
Igor Kostyukov
(Institute of Applied Physics RAS)
09/07/2013, 11:00
oral presentation
We discuss generation of energetic photons in strong laser field at intensities above 10^23 W/cm^2. First we discuss production of electron-positron-gamma-quanta plasma at QED cascading. QED or electromagnetic cascades are one of the basic phenomena of high-field physics. QED cascades can efficiently convert laser radiation into gamma-quanta. The various methods and schemes to control of the...
Dr
Selym Villalba-Chavez
(Institut für Theoretische Physik I, Heinrich Heine Universität Dusseldorf)
09/07/2013, 11:25
oral presentation
The quantum vacuum, polarized by a classical electromagnetic field, behaves as an active medium. Its absorptive and dispersive properties are studied in the presence of a high-intensity circularly polarized laser wave. The outcomes of this investigation reveal that, in the region relatively close to the threshold of the two-photon reaction, the birefringence and dichroism of the vacuum can...
Dr
Daniel Seipt
(Helmholtz-Institut Jena)
09/07/2013, 11:50
oral presentation
Non-linear Compton scattering in ultra-short intense laser pulses is discussed. The focus is on angular and azimuthal distributions of the emitted photon in intense single-cycle and few-cycle laser pulses. Asymmetries of the azimuthal distributions are predicted for both
linear and circular polarization. For linear polarization, the dominant direction of the emission changes from a...
Dr
Ben King
(Ludwig-Maximilians-Universität München)
09/07/2013, 12:15
oral presentation
Motivated by the ever-increasing interest in simulating the intense irradiation of plasmas by combining the scales of classical plasma physics and strong-field QED processes, we present the results of two studies into common approximations. First, we derived polarised non-linear Compton scattering and pair-creation rates in a constant crossed field and studied their inclusion in simulations,...
Dr
Antonino Di Piazza
(Max Planck Institute for Nuclear Physics)
09/07/2013, 14:00
oral presentation
A detailed analysis of the process of two-photon emission by an electron scattered from a high-intensity laser pulse is presented. The calculations are performed in the framework of strong-field QED and include exactly the presence of the laser field described as a plane wave [1]. We investigate the full nonlinear quantum regime of interaction with a few-cycle pulse, where nonlinear effects in...
Erez Raicher
(Hebrew University of Jerusalem, Israel)
09/07/2013, 14:50
oral presentation
We obtain analytical solutions of the Dirac and the Klein-Gordon equations coupled to a strong electromagnetic wave in the presence of plasma environment. These are a generalization of the familiar Volkov solutions. The contribution of the non-zero photon effective mass to the scalar and fermion wavefunctions, conserved quantities and effective mass is demonstrated for the first time. The new...
Dr
Florian Hebenstreit
(Heidelberg University)
09/07/2013, 15:10
oral presentation
We investigate fermion production in space- and time-dependent electric fields in 1+1 dimensional QED using real-time lattice techniques. We compute the non-equilibrium time evolution of gauge invariant observables and investigate the decay of the field due to the backreaction mechanism. The latter allows us to discuss the striking phenomenon of a linear rising potential building up between...
Prof.
Christoph H. Keitel
(Max Planck Institute for Nuclear Physics (MPIK))
09/07/2013, 16:00
oral presentation
The interaction of highly charged ions and nuclei with intense light sources is introduced [1]. We begin discussing the quantum relativistic bound electron dynamics in highly charged ions and super intense laser fields [2,3]. Then, special attention is devoted to laser-induced tunneling in the relativistic regime. Here, we show that an intuitive picture can be developed for relativistic...
Prof.
Gerald Dunne
(University of Connecticut)
09/07/2013, 17:00
oral presentation
The prospect of next-generation ultra-high-intensity laser sources has prompted recent renewed study of the Schwinger effect, in which the instability of the QED vacuum is probed by external fields. Experimental observation of this long-sought effect would provide controlled access to non-perturbative processes in quantum field theory under extreme conditions, which is of direct interest in...
Dr
Falk Bruckmann
(Regensburg University)
10/07/2013, 09:10
oral presentation
I review the recent progress concerning QCD with external fields, especially the catalysis resp. inverse catalysis of the quark condensate, the critical temperature, the magnetic susceptibility etc. from lattice simulations in comparison to other approaches.
Dr
Kazunori Itakura
(KEK Theory Center, IPNS, KEK)
10/07/2013, 09:35
oral presentation
Extremely strong magnetic fields appear in high-energy heavy-ion collisions and compact stars like magnetars. Under such strong magnetic fields, photons and even hadrons show unusual behaviors. In this talk, I will explain photon's vacuum birefringence and decay into an e+e- pair [1,2] and the conversion of neutral pions into (virtual) photons [3] both of which are possible in strong magnetic...
Naoto Tanji
(IPhT Saclay/ KEK)
10/07/2013, 10:00
oral presentation
A high-energy nucleus can be viewed as a condensed state of high-density and weak-coupling gluons, which is called color glass condensate. After a collision of heavy nuclei, these gluons are emitted between the two nuclei and they can be interpreted as coherent classical chromo-electromagnetic
fields polarized in the longitudinal beam direction. The strength of these fields is given by the...
Dr
Tigran Kalaydzhyan
(DESY)
10/07/2013, 10:20
oral presentation
We study electromagnetic and topological properties of the QCD vacuum and quark-gluon plasma in the background of strong (hadronic scale) magnetic fields comparable to the ones taking place in heavy-ion collisions. Among the properties are the following ones: electric conductivity, magnetization and magnetic susceptibility, local CP-violation and induced anomalous currents, distribution of the...
Prof.
Ralf Schuetzhold
(Faculty of Physics, University of Duisburg-Essen)
10/07/2013, 11:00
oral presentation
Recently it has been found that the superposition of a strong
and slow electric field with a weaker and faster electromagnetic
pulse can significantly enhance the probability for
non-perturbative electron-positron pair creation out of the
vacuum — the dynamically assisted Sauter-Schwinger effect.
After a brief introduction into the basics of this effect,
this talk will be devoted...
Dr
Sven Ahrens
(Max-Planck-Institut für Kernphysik)
10/07/2013, 11:25
oral presentation
The Kapitza-Dirac effect is the diffraction of electrons at a standing wave of light [1]. We solve the relativistic quantum dynamics of this electron diffraction by integrating the Dirac equation numerically and perturbatively in momentum space and demonstrate that spin-flips can be observed in the Kapitza-Dirac effect with three interacting photons [2]. Our recent work shows that significant...
Takuya Shibata
(Research Center for Nuclear Physics, Osaka University)
10/07/2013, 11:50
oral presentation
We propose a uniform formulation to calculate photon emission processes from a charged scalar field or spinor field under the strong laser field. One photon emission from a charged particle, which is forbidden in the vacuum, can be observed in the strong EM field, for example, SLAC E-144 experiment (1997). The process is expressed as non-linear Compton scattering, which means the number of...
Mr
Christian Kohlfürst
(University of Graz)
10/07/2013, 12:10
oral presentation
The process of electron-positron pair production in rapidly time-dependent and linearly polarized electric fields is investigated within the quantum kinetic formalism. Similarities between atomic ionization and pair production are pointed out for field parameters where the Schwinger effect (tunneling) is contributing but subdominant against multi-photon absorption (above-threshold ionization)....
Prof.
John Kirk
(MPI Kernphysik)
10/07/2013, 14:00
oral presentation
Current high intensity laser facilities can be used to reach the
regime in which electron trajectories are strongly modified by
the quantum equivalent of the radiation reaction force. We describe a
Monte-Carlo simulation of a set-up in this regime and present results in which GeV electrons counter-propagate into a 10^{22} W/sq cm laser pulse. These show that the stochastic nature of...
Dr
Nina Elkina
(Ludwig-Maximilians University of Munich)
10/07/2013, 14:40
oral presentation
The next generation of laser facilities will make possible to
study electron-positron laser plasma arising due to electromagnetic cascades.
The cascade consists of
quantum electrodynamic effects of hard photon
emission and electron-positron pair creation.
A central problem in description of
plasma with quantum electrodynamic effects is the need for a proper model for radiation,...
Dr
Christopher Harvey
(Queen's University Belfast, UK)
10/07/2013, 15:00
oral presentation
During the next few years a number of new laser facilities are expected to come online (such as ELI and XCELS). These will provide fields of unprecedented powers and intensities, allowing us to explore a range of physics under extreme conditions. In this talk I intend to discuss both classical and quantum aspects of laser-particle interactions and the boundary between the two regimes. I...
Mr
Timon Mehrling
(DESY)
10/07/2013, 15:20
oral presentation
High intensity laser- or particle beams excite large amplitude plasma waves when propagating in appropriate gas targets. The fields, carried by these plasma waves, can exceed 100 GV/m and are capable of accelerating particles to high energies within short distances. To design, advance and understand experiments, numerical investigations of the dynamics in such plasma accelerators are vital....
Prof.
Burkhard Kampfer
(HZDR)
10/07/2013, 16:10
oral presentation
Employing the AdS/QCD correspondence the graviton potential is adjusted in a bottom-up approach. Lattice QCD data for the equation of state at non-zero temperature serve as input. Transport coefficients follow then without further assumptions or fine tuning.
Dr
Alexander Fedotov
(National Research Nuclear University MEPhI)
10/07/2013, 16:40
oral presentation
Recently, a significant amount of attention is payed in the literature to the proposals for experimental observation of the so-called "Unruh effect" and "Unruh radiation", in particular via application of the state-of-the-art laser facilities. In the papers [1-4] we have reconsidered the original derivation [5] of the Unruh effect. This "effect" originates essentially due to splitting of the...
Shang-Yung Wang
(Tamkang University)
10/07/2013, 17:10
oral presentation
In this talk we will discuss interesting aspects of QED in an intense magnetic field in the context of nonperturbative QED. We show that thanks to the magnetic catalysis of chiral symmetry breaking (i) there is a few percent increase in the electron mass around $10^{15}$ Gauss, the typical magnetic fields on the surface of young neutron stars, and (ii) the magnetized QED vacuum is stable for...
Dr
Felix Karbstein
10/07/2013, 17:40
oral presentation
The photon polarization tensor is the central object in an effective theory describing photon propagation in the quantum vacuum. It accounts for the vacuum fluctuations of the underlying theory, and in the presence of external electromagnetic fields, gives rise to such striking phenomena as vacuum birefringence and dichroism. For homogeneous magnetic fields it is explicitly known at one-loop...
Prof.
Mitsuo Nakai
(Institute of Laser Engineering, Osaka University)
11/07/2013, 09:00
oral presentation
The GEKKO-EXA project[1] was revised depending on the domestic user’s demand. Here presented is a revised proposal for the GEKKO-EXA project. The project is aiming at the investigation of the physics under the intense laser field up to 10^24 W/cm^2.
As for the future application of the intensity laser, the intensity of 10^23W/cm^2 is one of the mile stone to be overcome since, in the region...
Babette Döbrich
(DESY)
11/07/2013, 09:20
oral presentation
The ALPS-II experiment at DESY combines expertise from cw-laser
precision setups with low-flux photon detectors
and high-field superconducting magnets to search for low-mass,
weakly-interacting particles (WISPs) such as axion-like particles. After a brief introduction to the scientific goals of the three ALPS-II
stages, I will review the crucial components of the setup,
and comment on...
Mr
Daniele De Gruttola
(Centro Fermi Roma and Salerno INFN)
11/07/2013, 09:40
oral presentation
The photoproduction of vector mesons in Ultra-Peripheral Collisions (UPC) is a powerfull tool to probe the nuclear gluon-distribution, for which there is considerable uncertainty in the low-x region. We present the first measurements in Pb-Pb collisions at √s_NN = 2.76 TeV, performed with the ALICE detector. The J/ψ is identified via its dimuon decay in the forward rapidity region and via...
Stefano Porto
(Hamburg University)
11/07/2013, 10:00
oral presentation
Future linear colliders will collide dense charge bunches generating
very intense electromagnetic fields at the IP, often approaching or even exceeding the Schwinger critical field in the rest frame of the
ultrarelativistic colliding particles. These strong fields affect all the processes happening at the IP, in particular, at 1st order, beamstrahlung and coherent pair production.
The dense...
Kristoffer Andersen
(Aarhus University)
11/07/2013, 10:20
oral presentation
The classical description of synchrotron radiation fails at large Lorentz factors for relativistic electrons crossing strong transverse magnetic fields. When the Lorentz factor times the magnetic field is comparable to the so-called critical field of 4.4 GT, quantum corrections are essential for the description of synchrotron radiation. The radiation emission drastically changes character; not...
Anton Ilderton
(Chalmers Univesity)
11/07/2013, 11:00
oral presentation
I will discuss recent theoretical results in radiation reaction (RR). In the first part of the talk I will describe how and where RR appears in QED, and the possibilities for measuring RR in different regimes and in different experiments (with say lasers, or Coulomb fields).
RR effects are expected to become significant in the regimes reached by next generation laser facilities. Aside from...
Rashid Shaisultanov
11/07/2013, 11:20
oral presentation
Radiation reaction effects, in particular the effects of stochasticity,
in dynamics of a high energy particle are studied by using semiclassical approach to radiation reaction.
Dr
Adam Noble
(University of Strathclyde)
11/07/2013, 11:40
oral presentation
Rapid advances in laser technology have hastened the need for a consistent and physically reasonable model of how losses to radiation affect the motion of electrons. We report on a recent investigation of the Ford-O'Connell equation, exploring its relation to other commonly used descriptions of radiation reaction, in particular that of Landau and Lifshitz. By analysing the motion of an...
Mr
Greger Torgrimsson
(Chalmers)
11/07/2013, 12:00
oral presentation
There remains great interest in radiation reaction, both theoretically and experimentally, especially in the context of strong laser fields.
In this talk I will derive classical radiation reaction directly from QED. The treatment is fully quantum and and we make no approximation except the usual coupling expansion of QED.
We calculate the expectation value of the momentum and the...
Dr
Sen Zhang
(Okayama Institute for Quantum Physics)
11/07/2013, 12:20
oral presentation
The Landau-Lifshitz equation is considered as an approximation of the Abraham-Lorentz-Dirac equation. The former is derived from the latter by treating radiation reaction terms as a perturbation. However, while the Abraham-Lorentz-Dirac equation has pathological solutions of pre-acceleration and runaway, the Landau-Lifshitz equation and its finite higher order extensions are free of these...
Dr
David Burton
(Lancaster University & Cockcroft Institute)
11/07/2013, 14:00
oral presentation
Contemporary advances in ultra-intense laser facilities have driven the recent surge of interest in the collective behaviour of charged matter in extreme conditions, and a particularly vexing topic in that context concerns the coupling of an electron to its own radiation field. In most practical cases, the Lorentz force on an electron, due to an applied electromagnetic field, is considerably...
Dr
Julia Grebenyuk
(DESY)
11/07/2013, 14:20
oral presentation
Plasma acceleration exploits extreme electric fields created in a plasma by high-current beams or high-intensity laser pulses, to accelerate charged particles. In current studies we explore prospects for beam-driven plasma acceleration within FLASHForward project at DESY, by means of 3D particle-in-cell simulations with the code OSIRIS. In particular, various techniques of injecting particles...
Mr
Tom Blackburn
(Clarendon Laboratory, University of Oxford)
11/07/2013, 14:40
oral presentation
The intensity of short pulse lasers is now sufficiently high that the dynamics of energetic electrons in these fields is dominated by quantum radiation reaction. We present simulations of an experiment that uses a laser wakefield to drive GeV electrons into a counterpropagating laser pulse of intensity 10^{22} Wcm^{-2}. The stochastic nature of photon emission leads to broadening of the...
Dr
Naveen Kumar
(Max-Planck-Institute für Kernphysik)
11/07/2013, 15:00
oral presentation
Stimulated Raman scattering of an ultra-intense laser pulse in plasmas is studied by pertur- batively including the leading order term of the Landau-Lifshitz radiation reaction force in the equation of motion for plasma electrons. In this approximation, radiation reaction force causes phase lag in nonlinear current densities that drive the two Raman sidebands (anti-Stokes and Stokes waves),...
Prof.
Matthew Zepf
(Queens University)
11/07/2013, 15:40
oral presentation
The development of ultra-intense lasers has brought Physics in intense fields
into sharp focus from a perspective of testing theoretical predictions -
some quite longstanding - for the first time. Reaching a significant
fraction of the critical QED field strength is still some way off for a real
facility, however many possibilities exist with current technology or
near-term achievable...
Prof.
Hartmut Ruhl
(Ludwig-Maximilians-Universität München)
oral presentation
We consider circular ultra-intense laser radiation interacting with a
rigid nano-foil within the attractive potential of an immobile ion background in 1D. We show that the foil performs an-harmonic oscillations and
has always a finite recurrence time that depends on the foil density and
the irradiation parameters of the laser radiation. Under specific radiation and density conditions the...
Prof.
Toshitaka Tatsumi
(Department of Physics, Kyoto University)
oral presentation
One of the interesting subjects may be a possible appearance of inhomogeneous chiral phases on the QCD phase diagram and their implications on high-energy heavy-ion collisions or compact stars [1,2]. Here we discuss their properties in a strong magnetic field. Theoretically the effect of the magnetic field causes interesting phenomena such as an enhancement of spontaneously symmetry braking...
