During the 20^th Century, quantum mechanics gradually provided an understanding of the properties of atoms, materials, and then of increasingly complex physical systems.

The strangeness of the quantum world, notably with non-local intrication between physically separate systems and superpositions of quantum states for macroscopic systems, passed from a curiosity status to the status of a real technical resource during the period 1980-1990.

Demonstration of quantum intrication, shown by the violation of Bell's inequalities, was actually followed shortly by very appealing proposals for exploiting this intrication in the field of information, with cryptography and quantum computation, as well as in that of highly accurate devices, with atomic clocks and interferometry with non-classical states.

New methods for cooling atoms with a laser and progress in micro- and then nano-manufacturing have allowed the production of quantum systems involving and combining atoms and/or molecules, which are intrinsically quantum objects, with electric circuits, which may themselves behave as completely artificial quantum atoms. Quantum physics is presently in a phase for applying and making use of the new concepts put forward during the recent decades, with full development of similar problems in fields which had hitherto remained quite separate.

Our goal is to go deeper in the understanding of quantum coherence and intrication, by merging the skills and advances of condensed matter physics and that of diluted media (atomic, molecular and optical physics), both highly developed in the Palaiseau-Orsay-Saclay triangle. The question is of designing and applying new quantum systems for putting to use the combination of coherence and intrication, with ambitious goals in the long term. Let us mention here the possibility of developing lasers, interferometers with atomic matter waves, systems with individually controlled interacting atoms, devices based on degenerate quantum gases, molecular circuits in which electric transport would be controlled at a molecular scale, and circuits with quantum bits prefiguring actual quantum information processors.

Moreover, collaborations with young regional start-ups are already foreseen for developing new advanced equipment, for example inertial sensors with matter waves, by relying on existing industrial platforms.

The Triangle de la Physique is a centre at the international forefront of atomic and molecular physics, which combines original experimental and theoretical achievements with a set of light sources with exceptional performance.

The great questions in particular relate to photo-stability of components of living entities and more generally to the flow of energy and electrons in molecular systems brought out of equilibrium. The proposed developments range from ultra-fast dynamics of electrons and nuclei, for example, resulting in selective fragmentation of macromolecules up to the growth of nanometric constructions and to the nano-spectroscopic study of their fictionalisation by molecules.

Complex material relates both to the actual object of study, such as complex fluids (polymers, surfactants, colloid particles, suspensions, porous and granular media, reactive fluids, etc.), complex surfaces (rough fractures), and to disordered systems (a large number of possibly contradictory degrees of freedom wherein frustration gives rise to glassy behaviours), and complex dynamics (nucleation/growth, complex flows, confined flows, turbulence, collective behaviours) involved in mixing processes, instabilities, growth fronts or reactions.

Statistical physics plays a unifying role in all these problems in which it is possible to pass from individual properties to collective behaviours. In this set of themes, two lines of strength emerge from the partner teams: confined fluids and disordered matter. Our project will consist of exploring new properties originating from confinement, on the one hand, and on the other hand developing experiments with which the emergence of dynamic length scales and collective behaviours may be studied in different examples of disordered systems (glasses, spin glasses, granular media, turbulence, etc.).

Many materials discovered during the last thirty years, such as rare earth or actinide compounds, superconducting cuprates, organic conductors, fullerenes, cobaltates, and geometrically frustrated compounds, have fundamental states and have laws of behaviour (superconductivity with an exotic symmetry order parameter, orbital orders), which can no longer be described by simple band theory approaches.

This is due to strong interactions between electrons, which often arise by the proximity of an insulating Mott state having original magnetic properties. Novel theoretical concepts are required for describing the nature of the metal state of these systems. The frontiers of this field today encompass artificial solids formed by atomic condensates trapped in optical lattices. The Triangle de la Physique will offer the possibility of promoting the remarkable position of the Plateau de Saclay, which concentrates in these fields internationally prestigious teams covering the whole of the spectrum ranging from the synthesis of materials to their theoretical study. It is expected to promote mastery and development of advanced experimental methods in its laboratory (structural studies, low temperatures, high pressures, local spectrometries: NMR, STM, EELS, magnetic and transport measurements) as well as around the large instruments (polarized neutrons at the LLB, resonant diffraction, ARPES, RIX at SOLEIL).

These approaches are essential for revealing and analyzing the original behaviours of correlated systems, thereby opening the path to the elaboration of materials with specific functions, and certainly to original applications in the medium term. The interdisciplinarity of the centre should reinforce links with solid-state chemists, promote developments of theoretical methods towards calculations that into account both correlation effects and realistic characteristics of particular materials and reinforce exchanges and competitiveness of our teams in a background of strong international competition.

The charge and the spin of the electron are intrinsically related in its quantum behaviour, but charge and spin have been used separately for a long time.

Classical electronics displaces electrons by only acting on their charge. Magnetic information recording uses the macroscopic expression of spin, the magnetisation of the magnetic material, for storing information.

Under the impetus of several recent discoveries, a novel electronics is emerging that associates the control of spin currents and charges in novel devices. This spin electronics is promising, with low dissipation and high rates, as well as with complete integration of the "memory", "transmission" and "calculation" functions for higher performance of nanoelectronic circuits.

In the longer term, the magnetism/optics connection due to spin-orbit interaction, and the low coupling of spin with its surroundings, promise spin-offs in the fields of optoelectronics and quantum information, with hybrid devices that will associate metals, oxides, semiconductors and molecules.

The Spintronics axis conducts research work at an early stage of these themes, with an excellent world standard.

The Extreme light pole groups twelve laboratories which develop and operate power lasers and the associated optics in order to study laser-matter interaction with very strong illumination, in all its aspects.

This activity, represented in the Triangle de la Physique by an exceptional concentration of means and skills, is already unquestionably and internationally recognized. The research work covers the whole of the interaction processes with a gas or solid target, ranging from non-linear optics of bound systems to ultra-relativistic optics of free electrons and ions in plasmas. The fundamental aspects form a consistent scope that is very rich in spectacular processes, which also has very strong potential for application.

Thus, the generation of Extreme UV and X radiation and the acceleration of charged particles, relatively under control in the non-linear and relativistic domains, are today used as sources with exceptional characteristics (ultra-short duration, peak luminosity, energy). These sources of light/particles open the perspective of dynamic studies at time scales of attoseconds, of studies of non-linear processes in the XUV and X domains, of building very compact performing accelerators. Ultra-relativistic optics, which is completely unexplored, encounters nuclear physics and high-energy physics.

The Extreme Light Infrastructure (ELI) laser project supported by the laboratories of the Triangle de la Physique now gives both a credible and a fascinating perspective on exploring this extreme domain.

The Extreme light centre sets three goals:

• Support development of a laser continuum, notably with power equal to or greater than 100 TW, in the perspective of ELI and up to its achievement;
• Promote application of the new sources of light and particles, in close partnership with the Fédération Lumière et Matière, which groups many users in the Triangle de la Physique, on the one hand, and the SOLEIL synchrotron and the Free Electron Laser project ARC-EN-CIEL on the other;
• Reinforce collaborative, experimental and theoretical studies of hot and dense plasmas, synergistically within the national framework of the Laser-Plasma Institute.

Photonic activities in the Triangle de la Physique are particularly significant and cover a very wide spectrum ranging from fundamental studies on individual objects (quantum boxes, etc), electromagnetic crystals (metamaterials, photonic crystals), and plasmonics right up to the making of components and their integration into systems.

They group around the same object of study teams with strong international visibility, working on technologies, components and systems, from the fundamentalist physicist to the industrialist, thereby allowing through-technology transfer evaluation of the conducted research work.

The goals within the scope of the network are to reinforce these fundamental studies in as varied fields as quantum information, photonics with micro- and nano-structured materials and nano-optics, as well as to develop new components which may be integrated into systems (such as telecommunications) or for closely related fields such as biophotonics.