2015 Robert Hofstadter Memorial Lecturer
Many fundamental experiments in quantum information have been performed with qubits, i.e. in rather low dimensional Hilbert spaces. Various experimental techniques have recently opened up discrete higher dimensions for experiments. These are particularly multi-mode interference and photon states with more complex wavefronts, like orbital angular momentum (OAM) states.
I will present some recent results focusing on OAM states and on verifications of entanglement in very high dimensions. So far, entanglement of quantum states with quantum numbers around 1,000 and of superposition in more than 100-dimensional Hilbert space have been realized. This may shed interesting light on the question of the quantum-classical transition. I will also discuss recent experiments for using some of these states in quantum communication with higher alphabets.
Entangled quantum states also provide novel ways for nonlocal imaging. Most recently, it was seen that one can obtain imaging where the photon interacting with the object does not even have to be detected. This exploits the fact that the phase of a product state cannot be localized.
Prof. Anton Zeilinger of the University of Vienna and the Austrian Academy of Sciences is a distinguished quantum physicist. Zeilinger received the 2007 Isaac Newton Medal of the Institute of Physics (UK) for "his pioneering conceptual and experimental contributions to the foundations of quantum physics, which have become the cornerstone for the rapidly-evolving field of quantum information." Zeilinger's other notable awards include the Wolf Prize (2010) and the King Faisal International Prize (2005). In 2005, Zeilinger was among the "10 people who could change the world," elected by the British newspaper New Statesman.