Theoretical Physics

Supports the development of qualitative and quantitative understanding of fundamental physical systems, ranging from the most elementary constituents of matter through nuclei and atoms to astrophysical objects and the cosmos. This includes formulating new approaches for theoretical, computational, and experimental research that explore the fundamental laws of physics and the behavior of physical systems; formulating quantitative hypotheses; exploring and analyzing the implications of such hypotheses analytically and computationally; and, in some cases, interpreting the results of experiments. Support is given for research and conferences in the following categories: elementary particle physics; nuclear physics; atomic, molecular, optical, and plasma physics; astrophysics and cosmology; gravitational physics, and a broad spectrum of topics in mathematical physics, described below. The effort also includes a considerable number of interdisciplinary grants.

In addition, the program supports infrastructure activities such as short- and long-term visitor programs, workshops, and research centers involving the participation of external scientists from universities, national laboratories, and industry, as well as graduate students and postdoctoral fellows.

Information for Principal Investigators

The categories listed below have separate Program Directors. These personnel are listed in the MPS/PHY Staff Directory.

Atomic, Molecular, and Optical Physics

The Atomic, Molecular, and Optical Physics program supports theoretical and computational research in all areas of atomic structure, the molecular structure of small molecules, electron, and atomic collisions, photoionization and photodetachment of electrons from atoms and small molecules, time-dependent interactions with atoms and small molecules, quantum optics, ultracold phenomena in Bose and Fermi gases and quantum information science.  Investigations primarily directed toward a theoretical understanding of  larger molecules or condensed matter systems should be directed toward the appropriate programs in the Division of Chemistry or the Division of Materials Research.

Nuclear Theory

The Nuclear Theory program encompasses the structure and reactions  of nuclei, and of hadrons in few-nucleon and nuclear environments, and the quark/gluon substructure expressed by QCD.  Supported research includes contributions to broad theoretical advances as well as model building and applications to experimental programs at facilities such as RHIC and Jefferson Laboratory, and to astrophysical phenomena.

Elementary Particle Theory

The Elementary Particle Theory program encompasses different theoretical tools for understanding the interaction of elementary particles at different energy scales. These include String Theory, Quantum Field Theory, Lattice Field Theory, Effective Field Theories, and Phenomenology based on the above theoretical tools. The program supports both formal string theory as well as string-theory-inspired model building.  However String Theory proposals which are primarily mathematical should consider applying to the Mathematical Physics program.  Predictions for upcoming experiments at the LHC involve Supersymmetric Model building, Grand Unified Theories, Extra Dimensions, String Inspired phenomenology as well as high order calculations in the Standard Model (of strong weak and electromagnetic interactions) to sort out what new physics might be discovered at the next generation of accelerators and cosmic ray and neutrino detectors. High precision simulations of QCD processes using lattice gauge theory are also a crucial ingredient for understanding present and future experiments at various collider facilities. Certain aspects of formal string theory are supported in Mathematical Physics.

Mathematical Physics

Proposals to the Mathematical Physics Program are evaluated by a PHY Mathematical Physics Panel, composed of physicists and mathematicians expert in the many varied aspects of the field. The areas covered include fundamental quantum theory, quantum field theory, string theory, nonlinear dynamics, fluid mechanics, turbulence, chaos and complexity, and statistical physics. The importance of the mathematics is a critical consideration along with the merit and implications for physics of the application. A proposal for which the mathematics is mainly computational or standard, though it could be very sophisticated, may be more competitive for funding in another program.

Astrophysics and Cosmology Theory

The Astrophysics and Cosmology Theory program supports proposals that primarily are involved with theoretical particle astrophysics and big-bang cosmology as well as more speculative string theory inspired cosmologies. Understanding the quarks to cosmos connection has been a recent focus of the program as well as better understanding the implications of the fluctuation spectra of the cosmic microwave background.  The cosmology and astrophysics research supported by the program is usually associated with people with training in particle theory and encompasses dark matter, dark energy, high energy cosmic rays as well as exotic cosmologies arising from Brane-world and String Theory scenarios. Cosmology and Astrophysics not covered by the above topics is supported by the Astronomy Program in MPS.

Gravitational Theory

The Gravitational Theory program supports research on classical and quantum gravity theory, including gravitational wave source simulations and other phenomena associated with strong field gravity and the interface between gravitation and quantum mechanics.

Theoretical Plasma Physics

Theoretical plasma physics is supported by the Plasma Physics Program, see that Program Description for more details: (http://www.nsf.gov/funding/pgm_summ.jsp?pims_id=503252&org=PHY&from=home)