Gleason-Busch theorem for sequential measurements

Gleason's theorem is a statement that, given some reasonable assumptions, the Born rule used to calculate probabilities in quantum mechanics is essentially unique [A. M. Gleason, Indiana Univ. Math. J. 6, 885 (1957)]. We show that Gleason's theorem contains within it also the structure of sequential measurements, and along with this the state update rule. We give a small set of axioms, which are physically motivated and analogous to those in Busch's proof of Gleason's theorem [P. Busch, Phys. Rev. Lett. 91, 120403 (2003)], from which the familiar Kraus operator form follows. An axiomatic approach has practical relevance as well as fundamental interest, in making clear those assumptions which underlie the security of quantum communication protocols. Interestingly, the two-time formalism is seen to arise naturally in this approach

When Torts is More than a Series of Accidents: Epstein on Torts

By using the Epstein book, the students learn the basics of torts in a way that is not frustrating, but in which they are still challenged by legal theory and pushed to think. Coupled with the interest and entertainment that are behind the choice of cases, I find the Epstein book to be very appropriate for our students. Of course, no book will fit everyone\u27s needs or styles of teaching. But if you can determine what it is you wish to emphasize, both substantively and doctrinally, you can use this information to assist in selection. If, like me, you want your students to see torts as a whole system of legal thought rather than a seres of entertaining cases or things gone wrong, then the Epstein book may be for you