Talks

In this talk I will report on a recent work [arXiv:0908.1583], which investigates general probabilistic theories where every mixed state has a purification, unique up to reversible channels on the purifying system. The purification principle is equivalent to the existence of a reversible realization for every physical process, namely that to the fact that every physical process can be regarded as arising from the reversible interaction of the input system with an environment that is eventually discarded. From the purification principle one can also construct an isomorphism between transformations and bipartite states that possesses all structural properties of the Choi-Jamiolkowski isomorphism in Quantum Mechanics. Such an isomorphism allows one to prove most of the basic features of Quantum Information Processing, like e.g. no information without disturbance, no joint discrimination of all pure states, no cloning, teleportation, complementarity between correctable and deletion channels, no programming, and no bit commitment, without resorting to the mathematical framework of Hilbert spaces.

The quest to understand the nature of dark matter is entering a remarkable data-rich era. Hypothetical stable, electrically neutral particles with TeV-scale mass and weak-strength couplings are a simple, theoretically appealing, but untested candidate for the dark matter. I will summarize recent results in both direct and indirect searches for dark matter, and highlight what upcoming data may teach us. I will also discuss the key role of accelerator-based experiments and novel astrophysical measurements in understanding dark matter and its connection to Standard Model physics. The prospects are particularly rich if dark matter interacts through new, non-Standard-Model dynamics, as recent cosmic-ray data may suggest. I will discuss a range of collider-based searches and fixed-target experiments under development to search for this dynamics, and the complementary sensitivity of searches for cosmic rays originating from dark matter annihilation in the sun.

The LHC will explore fundamental physics at a new energy frontier. A spectrum of new particles at the TeV scale is expected on two theoretical grounds: explaining dark matter and generating the electroweak scale. Understanding the properties of such particles can clarify the nature of dark matter, the origin of the weak scale, symmetries of nature, and the multiverse. These particles can be discovered by identifying collision events characteristic of new physics in LHC data. Their properties can be measured by characterizing such new physics events in terms of decay modes and basic kinematics. I will describe how this can be accomplished and exciting possibilities for what we may discover.

Final states involving hadronic jets are an important background to new physics processes in colliders, as well as a probe of QCD over a large range of energies. Because the physics of jets involves multiple energy scales, they are both complex theoretically and ideally suited to study using effective field theory techniques. In this talk I will discuss some recent progress in using effective field theory to describe the physics of jets.