Talks

In this talk, I will briefly review the recent progress on quantum computation and simulation in the trapped ion system, with particular emphasis on the idea of scaling (how to scale up the number of qubits). I will discuss ideas towards large-scale quantum computation/simulation based on the network approach or the use of transverse phonon modes in anharmonic traps and then review the recent experimental progress along this direction.  At the end of the talk, I will also briefly mention recent activities in Tsinghua-Michigan Joint Institute for quantum information.

Finding the exact, quantum corrected metric on the hypermultiplet moduli space in Type II string compactifications on Calabi-Yau threefolds is still an open problem. We address this issue by relating the quaternionic-Kähler metric on the hypermultiplet moduli space to the complex contact geometry on its twistor space. In this framework, Euclidean D-brane instantons are captured by contact transformations between different patches. We derive those by recasting the previously known A-type D2-instanton corrections in the language of contact geometry, covariantizing the result under electro-magnetic duality, and using mirror symmetry. As a result, we are able to express the effects of all D-instantons in Type II compactifications concisely as a sum of dilogarithm functions.