Since 2002 Perimeter Institute has been recording seminars, conference talks, and public outreach events using video cameras installed in our lecture theatres. Perimeter now has 7 formal presentation spaces for its many scientific conferences, seminars, workshops and educational outreach activities, all with advanced audio-visual technical capabilities. Recordings of events in these areas are all available On-Demand from this Video Library and on Perimeter Institute Recorded Seminar Archive (PIRSA). PIRSA is a permanent, free, searchable, and citable archive of recorded seminars from relevant bodies in physics. This resource has been partially modelled after Cornell University's arXiv.org.
In this talk I will discuss the question of how to characterize, in an operationally meaningful way, the inevitable disturbance of a quantum system in a measurement. I will review some well-known limitations of quantum measurements (facts), and give precise formulations of trade-off relations between information gain and disturbance. Famous examples among these limitations are the uncertainty principle, the complementarity principle, and Wigners theorem on limitations on measurements imposed by conservation laws.
Newtons methodology is significantly richer than the hypothetico-deductive model. It is informed by a richer ideal of empirical success that requires not just accurate prediction but also accurate measurement of parameters by the predicted phenomena. It accepts theory mediated measurements and theoretical propositions as guides to research Kuhn has suggested that along with revolutionary changes in scientific theory come revolutionary changes in methodology.
A theory governing the metric and matter fields in spacetime is {\it
Abner Shimony is well-known for, among other contributions, his seminal work on Bell inequalities, turning a philosophical question into an experimental one. In my presentation I like to remind us how this experimental field is nowadays feeding into applied science. This is happening both in terms of the involved technologies and in the conceptual tools.
I will report my efforts to describe elementary Quantum behaviours, specifically single-particle interference and two-particle entanglement, in an accelerating frame.
Entanglement swapping is such a powerful technique for dealing with EPR problems, that it can handle inefficient counters and Bell Theorems without inequalities, even for two particles. We will examine some of the results and pitfalls.
An experimental realization of our spin-1/2 particle version of the Einstein-Podolsky-Rosen (EPR) experiment will be briefly reviewed. In the proposed experiment, two 199Hg atoms in the ground 1S0 electronic state, each with nuclear spin I=1/2, are generated in an entangled state with total nuclear spin zero. Such a state can be obtained by dissociation of a 199Hg2 molecule (dimer) using a spectroscopically selective stimulated Raman process.
Feynman was probably correct to say that the only mystery of quantum mechanics is the principle of superposition. Although we may never know which slit a photon has been passing in a Youngs double-slit experiment, we do have a corresponding classical concept in classical electromagnetic theory: the superposition of electromagnetic fields at a local space-time point is a solution of the Maxwell equations.