Introduction and Overview. The present project concerns the fundamental investigation of nonlinear interaction of superstrong laser radiation of ultrarelativistic intensities with the high energy charged particle beams/relativistic solid-plasma-films, graphene/nanostructures as a matter state with unique nonlinearity, as well as elements of Circuit QED (Quantum Electrodynamics) -artificial atoms or superconducting contours with high nonlinear properties, revealing important nonlinear phenomena towards the production of matter-antimatter from the ultrastrong laser fields and vice versa: creation of hard x-ray – ?-ray lasers due to the induced annihilation of matter-antimatter and as an intermediate process to reach in general the high energy region of photons – High Harmonic Generation (HHG) on the mentioned quantum objects. The proposed investigations will also give us additional information about the high energy radiation-matter state in cosmic objects, specifically in the Galactic Centre and new aspects of macroscopic instability of such systems as powerful sources of particles and ?-ray, as well as more information about the dark matter. Regarding the latter it is important the investigation of minicharged ultralight fermions, as one of the main candidates of dark matter (like to axions). On the other hand, several extensions of Standard Model in Fundamental Particle Physics suggest the existence of new weakly interacting elementary particles of sub-eV masses. Hence, investigation of nonlinear QED processes with such particles in the superstrong laser fields will verify the existence of hypothetical minicharged particles, which may also serve as a tool for exploring low-energy frontier of Fundamental Particle Physics.
Concerning the problem of implementation of superintense x-ray/?-ray lasers, as a forward mechanism still remains the scheme of Free Electron Lasers (FEL), successfully developed in the past few years. At present there are three actual devices of FELs: LCLS, SPRING 8, and TESLA, being currently in progress in the so-called SASE (Self-Amplified Spontaneous Emission) regime providing coherent radiation of ultrarelativistic high brightness electron beams in a wiggler. Nevertheless, because there are no drivers or mirrors operable at x-ray wavelengths, these FEL systems operate in SASE regime in which the initial shot noise on the electron beam is amplified over the course of propagation through a long wiggler with the lengths in the order of several ten-to hundred meters. Therefore in this project we plan to investigate nonlinear schemes of quantum regimes of FELs towards the creation of small setup x-ray/?-ray lasers when the quantum recoil becomes comparable or larger than the gain bandwidth and quantum effects play essential role. In contrast to classical regime, where SASE amplifiers are essentially noisy amplifiers having spiky and fluctuating outputs and, as a consequence wide spectrum, one can expect significant narrowing of the output radiation spectrum in the quantum SASE regimes. Besides, we can expect the incomparable more effective gain of FEL at the nonlinear schemes of amplification/generation, and proposed in this project mechanisms practically may appear more reasonable for x-ray/?-ray FELs due to the smaller set up requirements.
One of the alternative ways to reach shortwave region for generation of intense coherent radiation in the current project it is proposed to use HHG process on the quantum objects of high nonlinear properties irradiated by intense pump laser pulses. Concerning this scheme of generation of shortwave coherent radiation over the past years the significant experimental progress has been achieved on atomic-molecular systems. In particular, to reach the far x-ray region one needs the atoms or ions with a large nuclear charge at which the problem becomes relativistic. So, we plan to investigate the HHG and shortwave radiation lasing from the coherent superposition states and super-radiation of atomic ensemble and develop these results for atoms/ions with a large nuclear charge, as well as for nanostructures and elements of Circuit QED with high nonlinearity, on the base of the relativistic quantum theory. It is expected that in these situations the efficiency of HHG process and, consequently the quantum yield of corresponding coherent radiation, will considerable enhance.
As an efficient mechanism for high energy ?-ray lasers, in this project it is proposed also the other nonlinear mechanism of stimulated annihilation of particle-antiparticle pairs, in particular, at the collective decay of unstable atoms such as positronium ones in coherent macroscopic state corresponding to Bose-Einstein condensate (BEC). Such two-photon beams of ?-ray, produced in the result of collective annihilation from BEC state, are entangled ensemble of photons. In this connection it is planned to investigate thoroughly the problem of ?-ray photons entanglement in two laser beams, which is of great importance for contemporary quantum physics. These investigations will have a special significance for astrophysical studies regarding the high energy processes in the Galactic Centre or in the accretion disks of superdense neutron stars and at the elaboration of observation results from these cosmic objects relating to high energy radiation characteristics.
Regarding the problem of novel laser-plasma accelerators of superhigh energies with high brightness particle beams, in the proposed project we will investigate nonlinear mechanisms of laser acceleration of charged particles, considering the processes with largest length of coherency of electron-supershort laser pulse interaction. From this point of view the induced Compton process at high energy electron beam scattering on the supershort opposite laser pulses of different frequencies, the induced synchrotron (in plasma with nonlinear cyclotron resonance) and undulator processes are of interest, as in these coherent processes the nonlinear-threshold phenomenon by laser intensity take place that opens new opportunities to achieve an incomparably large transformation coefficient of particle-laser interaction, i.e. the large gain for laser acceleration.
Competence of the project team in the specified area. The personnel of this project has great experience and high level of proficiency in the proposed field, particularly in the nonlinear theory of interaction of charged particles with strong radiation fields that has been developed since 1970 in the Yerevan State University, started with pioneer works of the Scientific Head and Manager of this project. These works provide principally new opportunities for implementation of FEL and laser accelerators via nonlinear schemes of electron beam-laser interaction. The scholars involved in the presented team are mainly former PhD students of the Project-Manager with a big experience of cooperative joint research. Besides, in this team are involved two leading specialists in the field of Nonlinear and Quantum Optics and Plasma Physics. The all participants are the authors of numerous publications concerning the mentioned problems and relevant issues of the project. Only during the last 5 years they have published in the leading international journals and reported at the International Conferences more than 100 papers on considering topic, as well as a monograph by the Project-Manager published by Springer, in New York.
Expected results and their application. It is expected that the results of the proposed investigations will be important at the construction of small setup devices of coherent radiation in far x-ray – ?-ray region, as well as compact unconventional accelerators of superhigh energies with high brightness particle beams. Short wavelength coherent radiation of x-ray/?-ray lasers may offer significant advantages in applications like holograms of microscopic biological structures, as well as in many fields where coherent, short wavelength radiation is required like holography and interferometry on a submicrometer scale etc. The next generation of particle accelerators will likely depend upon novel schemes of reaching the high energies necessary for exploring the future frontiers of physics. Laser acceleration is the main candidate for the solution of this challenging problem, besides it will have significant applications in medicine and Hi-Tech industry. Apart from the scientific significance, if the considering schemes of x-ray/?-ray lasers, or laser accelerators were operational, these devices would reduce greatly the sizes and costs of novel accelerators and projected x-ray FELs, the present size of which is several kilometers and cost is multi-hundred-million-dollar.
Meeting ISTC Goals and Objectives. The past and current scientific activities in the scope of ISTC provided integration of the presented team into the international scientific community give us new possibilities to direct entirely our knowledge and experience in the area of high energy physics, specifically, superstrong laser-QED vacuum-plasma-accelerator physics, Circuit QED and Nanotechnologies for the wider investigation of the problems presented in the current project towards the solution of scientific, economic, and contemporary civil problems. The character of the problems including in this project allows us to expect the promoting contribution of final results in the areas of nuclear and elementary particles physics, biology and medicine, chemistry and for other civil goals.
Scope of activities. The project involves basic theoretical investigations of nonlinear interaction of superstrong laser radiation with the high energy charged particle beams/relativistic solid-plasma-films, nanostructures/graphene, Circuit QED elements, QED vacuum with hypothetical minicharged particles for production of matter-antimatter from the ultrastrong laser fields and creation of ?-ray lasers due to the induced annihilation of matter-antimatter and in general implementation of high energy sources of super-bright particles and photon beams of new generation etc. The Project can be divided into 4 major Tasks: (1) Positronium Atoms and Electron-Positron Plasma for Generation of Intense Coherent ?-ray; (2) Nonlinear Interaction of High Energy Particle Beams and Relativistic Solid-Plasma-Films with Superintense Laser Radiation; (3) Nonlinear Interaction of Coherent Radiation with Graphene/Nanostructures and Elements of Circuit QED with high nonlinearity; (4) Creation/Annihilation of Ultralight Minicharged Fermions in Superintense Laser Fields and Astrophysical Applications.
Technical approach and methodology. Theoretical methods for the solution of the proposed tasks are based mainly on the new approaches developed by us at the previous investigations of these and analogous problems. The problems of production of matter-antimatter from the ultraintense laser fields and induced annihilation of matter-antimatter for creation of ?-ray lasers will be solved via the specially developed multiphoton resonance method for the solution of Dirac equation for electrons and positrons, and for photonic field amplification – Maxwell and relativistic quantum kinetic equations. The similar multiphoton resonance approach will be developed at the solution of the problem with minicharged fermions obeying the Dirac equation (by nonlinear excitation of QED vacuum in the superstrong laser fields). Radiation processes in atomic-molecular systems will be studied on the base of the self-consistent set of Maxwell and generalized Bloch equations with standard methods of Quantum Electrodynamics. The problem of x-ray – ?-ray lasers will be treated by the self-consistent set of Maxwell and relativistic quantum kinetic equations on the base of the second quantized Hamiltonian formalism.
Role of foreign collaborators. The role of collaborators will be general participation in analyses and elaboration of results to search for more effective ways of gaining ultimate results for realization of considered problems. The general guidance by collaborators during the process of problem solving will move the research towards the other actual goals, taking into account the contemporary experimental base and possibilities of Collaborating Countries in this field. The YSU team and collaborators will be in close contacts throughout the implementation of the project by regular E-mail correspondence, discussions at the conferences and planned special visits to the Collaborators’ Institutions to represent and consider obtained new results regarding the main problems of project tasks. As an important activity of the collaborators will also be the review of the Work Plan, as well as the evaluation of the annual and final reports of the project.
