**Strategy of Department of Theoretical Physics**

**Main directions of research**

Theoretical physics research at IFIN-HH covers a distinctively broad range of topics an is reconized for its excellence by the international community. The goal is to continuously improve our research work, to establish theoretical physics research as a brand image of the Institute.

**A. Theory of Nuclear Decay Reactions and Nuclear Structure **

• Study, analyse and predict fundamental properties of atomic nuclei at the limits of stability and investigate structure peculiarities of superheavy and exotic nuclei;

• Study dynamics of decay processes at low and intermediate energies accompanied by production of stable as well as radioactive nuclides; develop rigorous and effective mathematical methods of calculations of their basic properties;

• Explore the nuclear matter properties and its phase transitions at extreme values of excitation energy, spin, Z/N ratio and nuclear density;

• Synthesis and decay of super-heavy elements, study of nuclear structure by particle emission processes, clusters and fission, exotic nuclei far from the line of stability;

• Anharmonic and multiphononic states in atomic nuclei, heavy ion nuclear potential;

• Microscopic and phenomenological models of nuclear structure, phase transitions in finite systems, contractions of Lie groups and symmetries corresponding to the critical point of phase transition, double beta decay, statistical aspects of nuclear multifragmentation, special aspects of classical and quantum chaos in nuclear systems;

• Nuclear and subnuclear matter (phase transitions, physics of neutron stars);

• Dynamics of nuclear reactions at low, intermediate and relativistic energies (fusion, nuclear multifragmentation, stellar synthesis, transition to quark-gluon plasma);

• Phenomenological models for alpha decay, heavy cluster emission, nuclear fission, collective bands in heavy nuclei;

• Microscopic models (density functional theory, no-core shell model, effective field theory and chiral models for nuclear interactions) for nuclear fission, collective excitations;

• Nuclear astrophysics – processes of nucleosynthesis, study of compact stellar objects (neutron stars, infinite, dense and superdense nuclear matter/neutron stars in nucleonic and quark phases);

• Equation of state of nuclear matter and transport models (quantum molecular dynamics) for intermediate/relativistic heavy-ion physics; deconfinement phase transition investigation by describing theoretically the dilepton and charmed particles emission spectra.

**B. Particle Theory and Quantum Fields**

• Theoretical investigations of specific observables and processes in the standard model (SM) and beyond the SM

- precision tests of the SM at low and intermediate energies

- hadronic form factors, heavy baryons

- spectroscopy of scalar mesons

- neutrino physics

- implementation of theoretical models in event generators

• Nonperturbative aspects of gauge field theories

- use of causality and unitarity in phenomenological studies

- behavior of all order quantities in quantum field theories

- discretizations of field theories

- physical processes in strong external electromagnetic fields

• Structural aspects of classical and quantum field theories

- gauge invariance and anomalies in the causal approach

- nonlocal field theories in reduced dimensionality and solvable models

- noncommutative and random tensor models in three and four dimensions

- continuum limit of discrete theories and relevance for quantum gravity

• Symmetries and conservations laws as basic tools in the investigation of physical systems

- generalized symmetries on curved spaces

- symmetry analysis of physical processes in external fields

- general formalisms for the description of dynamics

- singularities in general relativity and cosmological models

• Beyond the standard model and phenomenology of supersymmetric models

- supersymmetric models

- alternatives to the supersymmetric versions of the SM

- the naturalness problem

- dark matter models

• String theory in particle physics and cosmology

- string and F- theory model building

- flux and orbifold compactifications, effective supergravity theories

- moduli stabilization, supersymmetry breaking

- nonperturbative effects, grand unification, models of inflation.

**C. Mathematical Physics**

• Superstring theory (topological field theory, string field theory, dualities and conformal field theories, advanced mathematical methods in renormalization theory, extensions of combinatorial matrix models to the tridimensional case, singular space-times and black holes);

• Geometric methods in quantum physics, quantum optics, study of symmetries using theory of representations, geometry of coherent states, representations of Jacobi-type groups with applications to quantum squeezed states;

• Nonlinear integrable dynamical systems - discrete and supersymmetric integrability, cellular automata, resolutions of singularities and algebraic entropy using techniques from the algebraic geometry of rational elliptic surfaces, integrable soliton-hierarchies described by infinite-dimensional Lie algebras and super-algebras, integrability and super-integrability of geodesic equations on curved spaces with various geometries;

• Nonlinear dynamics of conservative and dissipative systems, localized structures in optics, fluids, plasma and interface plasma-short pulse lasers (study of soliton dynamics, pattern formations, stability, self-focusing, and weak (integrable) turbulence);

• Advanced computational methods in nonlinear photonics, Bose-Einstein condensate and in quantum and nuclear processes (numerical methods and high performance software, including by parallel and distributed Grid computing on multicore systems).

**D. Quantum Information Theory**

Quantum Information Processing and Communication has the potential to revolutionize many areas of science and technology:

- it exploits fundamentally new modes of computation and communication, because it is based on the physical laws of quantum mechanics instead of classical physics

- it holds the promise of immense computing power beyond the capabilities of any classical computer

- it guarantees absolutely secure communication

- it is directly linked to emerging quantum technologies.

• Study of fundamental aspects of quantum mechanics and quantum information theory (principles of quantum mechanics – wave-particle dualism, quantum channels etc);

• Study of quantum correlations (entanglement, discord etc) in quantum systems of discrete or continuous variables;

• Study of quantum processing and transmission protocols of quantum information (quantum teleportation, quantum cryptography, quantum computing);

• Application of models and methods of quantum information theory to quantum technologies (quantum imaging etc);

• Study of dissipative phenomena in open quantum systems, role of quantum decoherence in processing and transmission of quantum information.

**E. Condensed Matter and Nanophysics**

• Theoretical materials science:

- it ranges from new superconducting materials, magnetic materials, to more complex structures, like photo-voltaic cells and topological insulators;

- in a more loose sense it also includes systems of reduced dimensionality, like graphene and nanotubes; this is an area of overlap between materials sciences and nanophysics;

- it is essential in almost all areas of technological development and has direct economical consequences.

• Theoretical nanophysics:

- q-bits and development of quantum computers;

- structures of reduced dimensionality for technological applications;

- nanosensors for medicine, security, and fundamental science;

- functional materials;

- application in medicine, like drug delivery.

• Statistics

- It is an essential tool in almost all areas of physics, especially in condensed matter and nanophysics;

- It is becoming more and more useful in social sciences and economics, which are strategic research directions in Romania and in general, in the developed countries.

• Theoretical biophysics

- Although it is an independent research area, biophysics relies heavily on statistics and nanophysics. This is a very dynamic field of research with major implications in medicine and economics.

• Interaction of electromagnetic radiation with condensed matter - it is a research area of importance from the perspective of the ELI-NP experiment.

**CONTACT**

Prof. Dr. Aurelian ISAR

Email:
This e-mail address is being protected from spambots. You need JavaScript enabled to view it

Phone: 004 021 404 6254