Events at Physics
Events on Friday, March 4th, 2016
- Atomic Physics Seminar
- Quantum information with cold atom ensembles: beyond continuous variables
- Time: 11:00 am
- Place: 5310 Chamberlin
- Speaker: Tim Byrnes, NYU
- Abstract: An alternative framework to quantum information and computation based on spin coherent states is proposed. Traditionally quantum computing approaches are formulated in terms of either discrete (qubit) or continuous variables. Our approach offers an alternative third path, naturally suited towards implementations in cold atom ensembles and BECs. The scheme is illustrated by an application to quantum algorithms and we discuss the effects of decoherence induced by the large number of particles in the BEC. In particular, we discuss a quantum teleportation protocol that allows for the transfer of spin coherent states beyond the usual continuous variables formalism. The scheme differs from existing protocols in that a large ensemble of spins is teleported, rather than a qubit variable, resulting in a type of macroscopic teleportation. Other techniques such as phase contrast imaging and Deutsch-Jozsa algorithm in a beyond continuous variables context are also discussed.
- Host: Saffman
- Physics Department Colloquium
- Understanding when we can trust climate models: Characterizing uncertainty in climate change from global to regional scales
- Time: 3:30 pm
- Place: 2241 Chamberlin Hall
- Speaker: Chris E. Forest, Penn State
- Abstract: Uncertainty in regional climate predictions is a critical component of understanding risks of future climate impacts. Unfortunately, while State-of-the-science Earth System Models show consistency with observations at global and hemispheric scales, they show limited skill in reproducing climate change at sub-continental and smaller scales (i.e., regional scales) despite their ability detect and attribute climate change at global to continental scales. Significant internal/chaotic climate variability is one reason for this lack of skill. Structural uncertainty in modeling the physical climate system is an additional issue. Uncertainty in the centennial timescale trajectory of greenhouse gases and other factors impacting long-term changes is yet another component. In this talk, we will discuss components in climate models that lead to these uncertainties with a focus on basic physical processes related to both global and regional climate change.
- Host: Susan Nossal