In the last two decades, spectacular advances have been made in the quantum state control of ions confined in radiofrequency traps. Methods have been developed for laser cooling of the external motion down to the vibrational ground-state. Sympathetic cooling extended these techniques to many atomic and molecular species that cannot be directly laser cooled. Progress in ion transport allows performing each task in a separate, specifically optimized trap. As a result, trapped ions now represent one of the most advanced systems in the fields of quantum information and high precision measurements. This project aims at overcoming two important open questions of these techniques, which are still preventing investigation of highly interesting light ion species. Firstly, the above results were obtained with ions directly created inside the trap by electron impact or photo-ionization. However, many species such as antimatter ions, state-selected molecular ions, or highly charged ions are produced in external sources. We plan to develop a universal setup for transport, capture, and cooling of externally produced ions. The second challenge comes from the sympathetic cooling process, which becomes less efficient as the difference between the charge-to-mass (q/m) ratios of the laser-cooled and sympathetically cooled species increases, both for Doppler and ground-state cooling. We will experimentally investigate sympathetic cooling dynamics in the regime of high q/m differences, and develop cooling methods and trap geometries specifically adapted to this case. Taking advantage of both partners’ skills, a complete set of methods and instrumentation to load multi-species ion crystals will be developed. The proposal relies on a sequence of two linear, segmented traps: a “capture trap” where Doppler sympathetic cooling will allow reducing the temperature to the mK range, before transport of spectroscopic ions to a “precision trap” optimized for ground-state cooling of a two-ion crystal. We aim at optimizing the scheme so that even a pair of ions with highly different q/m ratios can be cooled. These developments will allow scientific breakthroughs in the fields of fundamental gravitation and physical constants determination. The first application is the GBAR project accepted by CERN in 2012; it concerns the first test of the equivalence principle with antimatter, through a free-fall experiment on neutral antihydrogen atoms. Both partners of the present project are among the 14 members of this international collaboration, and are involved in a key step: ground-state cooling of an antihydrogen positive ion in a Hbar+/Be+ ion pair. Our objective is to deliver the core of the GBAR experiment, complete setup for Hbar+ capture and cooling, tested with H+ ions before final assembly in 2017 at CERN. The second application is spectroscopy of state-selected cold H2+ ions, that will result in a new determination of the proton-to-electron mass ratio with about 10-10 accuracy (limited by theory), i.e. an improvement by a factor of 4. This binational project sets up a new collaboration joining rich competences in complementary fields of ion trapping and spectroscopy to overcome the demanding technical and physical challenges. The French partner’s experience in light ion production and manipulation, high-resolution spectroscopy, Be+ ion cooling laser sources, and the German partner’s experience in trap design, quantum control and transport of trapped ions are essential assets for the positive outcome of the project The BESCOOL project will provide novel and universal instrumentation for future spectroscopic applications and fundamental tests using light atomic and molecular ions. Among the exciting prospects is laser spectroscopy of highly charged ions for tests of quantum electrodynamics, quantum logic clock applications, and studies on time variations of fundamental constants.

This proposal is at the overlap of two important fields, the one of strongly correlated material (electronic correlations are at the origin of magnetism or superconductivity properties...) and the one of nano-structuration (whose may furthermore modulate the physical properties by surface or confinement effect). It will also push forward the nano-characterization aspect that is a key issue in nano-science. It will be focused on the engineering of the physical properties in diluted magnetic oxide semiconductor where spin acts as a new degree of freedom of the electron opening spintronic application. We aim to unravel the underpinning physical mechanism for such ferro-magnetism. We will thus evaluate the respective role of the nanoparticle size, micro- and nano-structure, defects (oxygen vacancy in CeO2 and TiO2..) and dopant (Fe, Cr…) on the magnetism of nanoparticles and also the possibility to maintain such properties for bulk nano-structured ceramic material. The aim of this project is to reveal the relationships between crystal structure, electronic structure and physical properties of diluted magnetic semiconductor, and in the case of Ceria CeO2, to obtained well controlled room temperature ferro-magnetism. Such comprehensive study is a prerequisite for further application, such as for spin-injecting material for the case of diluted magnetic semiconductor. Technological breakthrough will also be directly addressed in the research program since new nano-characterization device for scanning transmission electron microscopy will be built and bulk material will be synthesized. The strategy we have adopted to tackle this aim is based on(i) A well controlled nanostructuration and densification: Since influence of the doping and of the crystal size has to be evaluated, we chose methods which can synthesize nanomaterials of uniform size (size will range from 3 nm to 20nm), such as thermal decomposition method. Doping and post treatment will also be done to modulate the defective content and nature of the nanoparticles. Densification will be done using Spark Plasma Sintering technique, which may maintain part of the nanostructuration during the densification.(ii) A quantitative description of the nanoparticle and densified ceramics structures: A state of the art scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy will be performed (EELS). This includes the conception and assemblage of a new EELS detector that will allow local elemental quantification even for dopant analysis in nanostructure. Numerical modelization of the particle/ceramics structure (defect, surface..) will also been obtained though DFT relaxed energetic. (iii) The understanding of the key parameter in the electronic structure: A combination of synchrotron spectroscopies such as XES (X-ray emission), XAS (X-ray absorption), XMC(L)D (X-ray magnetic circular-linear dichroism), RIXS (resonant inelastic scattering) will be performed. By combining these methods, the main electronic parameter (d-d, f-f, charge transfer excitations…) controlling the physical properties of correlated system will thus be accessible. Furthermore, development of In-situ soft-x-ray spectroscopy will enable spectral measurement of the nano-particles electronic structure under wet condition. High-pressure hard-X-ray spectroscopy will also be done and the modulation of the pressure (up to several GPa) will change electronic correlation and the magnetism properties. Ab-initio (DFT, LDA+U) and parametrical (multiplet) numerical calculations will be used to relate spectroscopy measurement and ground state properties. Higher theoretical level for integration of the electronic correlation, such as DMFT (dynamic mean field theory), will also be done in order to interpret the experimental data and to elucidate the main magnetism mechanism.

The goal of this project is to identify the extent to which the environment of a quantum system can be actively utilized for coherent control by tailored external electric fields. The ability to manipulate quantum systems is an essential requirement for future applications of quantum technologies, and has been successfully demonstrated for isolated systems. However, most technologically relevant quantum systems cannot be considered isolated, and the induced decoherence is a major obstacle to quantum control. In particular, we will focus on condensed phase systems where the environment shows memory effects when responding to the driven system dynamics. This situation is termed nonMarkovian, and has attracted a lot of interest recently, since in principle it allows for a back-flow of information from the environment back into the system. The main idea of the proposal is to use this particular feature in the context of coherent control, i.e. to answer the question if memory effects due to specific environmental modes, which cannot be addressed directly by the control fields, can actually increase a predefined control objective, or even make specific objectives accessible, i.e. enhancing the controllability. The approach envisaged follows a line from general control theoretical considerations via the modeling of realistic non-isolated quantum systems to experimental realizations in semiconductor quantum dots and dye molecules in solution. As main outcome we expect novel and alternative control scenarios, which go beyond the known strategies relying on decoupling or isolating the system from its environment, and which offer new possibilities in steering non-isolated quantum systems, by specifically exploiting the interaction with their environment. The proposal relies on bringing together experts from different fields, ranging from the fundamental aspects of optimal control theory, the description of open quantum systems, in particular in the context of non-Markovian dynamics, experts in chemical physics and semiconductor physics for realistic simulations, and one of the world leading groups in experimental laser control. We believe that this approach will allow us to significantly advance the current fundamental understanding of the control of open quantum systems, in particular by exploiting non-Markovian effects, with important implications for many technologically relevant quantum systems embedded in very different environments from new materials to life science structures, well beyond the field of atomic and molecular physics.