Invited Talk on Quantum Reference Frames and Causality by Prof. Caslav Brukner
Date: 2019-06-02 Source:
Prof. Caslav Brukner from University of Vienna was invited by the Research Center for Quantum Computing and delivered a speech at Peng Cheng Laboratory on May 30. Prof. Brukner is a Full Professor at the University of Vienna, Austria and the director of the Institute of Quantum Optics and Quantum Information in Vienna (IQOQI-Vienna), and he was a Chair Professor at Tsinghua University from 2005 to 2008. His primary research interests are foundations of quantum physics and quantum information theory with particular emphasis on quantum non-locality, reconstructions of quantum mechanics, quantum communication complexity and quantum-to-classical transition.
Titled “Quantum Reference Frames and Causality: From Fundamentals to Application”, Prof. Brukner’s speech mainly addresses two foundational aspects from the interface between quantum and space-time physics: quantum reference frames and the indefinite causal structures. In the speech, Prof. Brukner introduced and explained the concept of “quantum causal structures”. In the classical sense, the operational order is either from A to B, or from B to A. However, the quantum causal structure allows such a situation where the experimenter can use the method of quantum coherence to “simultaneously” complete the experiment from A to B and B to A, i.e. A and B at this time have no definite operation sequence. This phenomenon is called “indefinite causal structure” and can be used to design a type of verifiable quantum computing protocols which have been experimentally verified. In addition, Prof. Brukner in his speech introduced the process of bringing the quantum causal structure into three-dimensional space-time, and discussed the influence of a large mass on the sequence of operations, thus enriching our understanding of time and space.
The audience communicated with Prof. Brukner in the Q&A session.