### Department Research Activities:

High Energy Theory

The members of the High Energy Theory Group have broad interests in string theory, quantum field theory, and the connections between the two. Some of the questions being pursued:

- How can we use string theory to solve QCD and other quantum field theories?
- Can we evaluate the QCD path integral numerically and obtain the masses of strongly interacting particles, their decay properties, and the properties of matter at high temperature?
- What is string/M-theory - what is the underlying principle and the precise and complete formulation?
- Is it string field theory, the holographic principle, gauge/gravity duality?
- Can we find toy models that capture some of the essential physics of string theory and quantum gravity?
- Can we use quantum field theory to solve biological questions, such as the folding of RNA and the processing of information?
- What happens to information cast into a black hole?
- Can we use quantum chaos theory to understand the emergence of thermal behavior in isolated systems, and also the quantum properties of black holes?
- What does string theory say about the physics at spacetime singularities, where ordinary general relativity breaks down?
- Can extra dimensions explain the cosmological constant or "dark energy"?
- Is the dark matter a stable supersymmetric particle?
- Can black holes be produced at particle accelerators?
- What is the space of vacua in string theory, and what can we deduce about observable physics in four dimensions?
- Might there be superstrings of cosmic size in the universe today?
- What important question are we overlooking?

Our interests strongly overlap those of the Gravity and Mathematics Groups. In addition, the Kavli Institute for Theoretical Physics (KITP) brings in leading theorists from all areas of physics, as well as a lively group of postdocs.

Recent and upcoming KITP programs include Mathematical Structures in String Theory, Modern Challenges for Lattice Field Theory, QCD and String Theory, Collider Physics, and Superstring Cosmology.

Research efforts within the UCSB High Energy Theory Group include:

**David Berenstein**: Large N Gauge Theory and String Theory**Nathaniel Craig****Steve Giddings**: Quantum gravity, quantum field theory, quantum cosmology, elementary particles**David Gross**: High Energy Physics, Quantum Field Theory, String Theory**Joe Polchinski**: String Theory, Quantum Field Theory, and Duality**Mark Srednicki**: Quantum Chaos and Astroparticle Physics**Bob Sugar**: Lattice Gauge Theory**Tony Zee**: Applications of Quantum Field Theory in Physics and Biophysics