From one of the directors of LSE’s Center for Philosophy of Natural and Social Science, Roman Frigg:

Below is this term’s Sigma Club programme. As always, talks are from 5.15pm to 6.45pm in LAK206, preceded by a tea at 4.45pm in the Centre’s common room on the 1st floor. Further details can be found at http://www2.lse.ac.uk/CPNSS/events/SigmaClub/Home.aspx

29 October

Gábor Hofer-Szabó, Institute of Philosophy, Hungarian Academy of Sciences

Bell Inequality and Common Causal Explanation in Algebraic Quantum Field Theory

In the talk it will be argued that the violation of the Bell inequality in algebraic quantum field theory does NOT exclude a common causal explanation of a set of quantum correlations if we abandon commutativity between the common cause and the correlating events. Moreover, it will turn out that the common cause is local, i.e. localizable in the common past of the correlating events. It will be argued furthermore that giving up commutativity helps to maintain the validity of Reichenbach’s Common Cause Principle in algebraic quantum field theory.

19 November

Giovanni Valente, Department of Philosophy, University of Pittsburgh

Local Disentanglement in Relativistic Quantum Field Theory

In their paper on “Entanglement and Open Systems in Algebraic Quantum Field Theory”, Clifton and Halvorson (2001) raised the question whether entanglement between quantum systems can be destroyed by means of local operations and claimed that, contrary to non-relativistic quantum mechanics, this can never be the case in relativistic quantum field theory. In this talk I will argue that Clifton and Halvorson’s no-go result applies only to a special kind of local operations, and thereby I will reject their conclusion. In fact, after providing sufficient conditions for local disentanglement to be achieved, I will show that, if the split property holds, there exists a class of local operations which disentangle all states across any pair of spacelike separated quantum field systems.

3 December

Hugo Touchette, School of Mathematical Sciences, Queen Mary, University of London

The large deviation approach to statistical mechanics: A basic introduction

I will give in this talk a basic overview of the theory of large deviations, developed in 1970s by Varadhan (Abel Prize 2007), and of its recent application in statistical mechanics. In the first half of the talk, I will discuss basic results of large deviation theory, which can be traced back in mathematics to Cramer (1938) and Sanov (1960), and on the physics side to Einstein (1910) and Boltzmann (1877). In the second half, I will then discuss how these results can be used to rebuild or re-interpret the foundations of equilibrium and nonequilibrium statistical mechanics.