Talks by Guido Bacciagaluppi, David Wallace and Andrea Oldofredi

[Dardashti, Radin]

Speaker: Guido Bacciagaluppi (Aberdeen)
Date: Tue., April 14
Location: Geschwister-Scholl-Platz 1, E210
Time: 16:00 -⁠ 18:00

Title: The Misleading Equivalence of Decoherence and Branching

Abstract:
Well-known theorems relating decoherence and branching suggest
using the time-arrow of decoherence to explain the macroscopic branching
structure of the Everettian multiverse. It is argued by general 
considerations
and in a toy model that branching can be explained naturally also in the 
case
of time-symmetric decoherence as a purely perspectival effect of 
coarse-graining
over 'records' of future events. This result may impinge on the 
discussion of identity,
uncertainty and probability in Everett.

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Speaker: Guido Bacciagaluppi (Aberdeen)
Date: Thu., April 16
Location: Hans-Kopfermann-Str. 1, Campus Garching, MPQ, seminar room 
B2.46
Time: 14:00 -⁠ 15:00

Title: Leggett–Garg Inequalities, Pilot Waves and Contextuality

Abstract:
In this talk we first analyse Leggett and Garg's argument to
the effect that macroscopic realism contradicts quantum mechanics. After
making explicit all the assumptions in Leggett and Garg's reasoning, we
argue against the plausibility of their auxiliary assumption of 
non-invasive
measurability, using Bell's construction of stochastic pilot-wave 
theories as
a counterexample. Violations of the Leggett–Garg inequality thus do not
provide a good argument against macrorealism per se. We then apply
Dzhafarov and Kujala's analysis of contextuality in the presence of 
signalling
to the case of the Leggett–Garg inequalities, with rather surprising 
results. An
analogy with pilot-wave theory again helps to clarify the situation.

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Speaker: Guido Bacciagaluppi (Aberdeen)
Date: Fri., April 17
Location: Hans-Kopfermann-Str. 1, Campus Garching, MPQ, seminar room 
B0.22
Time: 10:15 -⁠ 11:45

Title: Did Bohr Understand EPR?

Abstract:
Contrary to widespread belief, I argue that Niels Bohr's arguments
in his reply to Einstein Podolsky and Rosen in 1935 take fully into 
account the
separation between the two particles. Specifically, I argue that there 
is no
sleight of hand in the passage from Bohr's discussion of a single 
particle
passing through a slit and his subsequent discussion of the EPR example.

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Speaker: David Wallace (Oxford)
Date: Wed., April 15
Location: Ludwigstr. 31, ground floor, room 021
Time: 16:15 -⁠ 17:45

Title: Statistical mechanics from an emergentist viewpoint

Abstract:
  I sketch a view of the philosophy of statistical mechanics as (a) 
concerned primarily with the interrelations between different dynamical 
systems describing more or less coarse-grained degrees of freedom of a 
system, and only secondarily with thermodynamic notions like equilibrium 
and entropy, and (b) informed by developments in contemporary mainstream 
physics. I develop, as concrete examples, (i) the projection-based 
approach to kinetic equations developed in the 1970s by Balescu, 
Prigogine, Zwanzig et al, and (ii) the relevance of quantum mechanics to 
nominally “classical” systems like the ideal gas.

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Speaker: Andrea Oldofredi (Lausanne)
Date: Thu., April 16
Location: Ludwigstr. 31, ground floor, room 021
Time: 12:15 -⁠ 13:45

Title: Extensions of Bohmian Mechanics to Quantum Field Theory (WIP 
Talk)

Abstract:
The aim of this talk is twofold: firstly I will show the extensions of 
Bohmian Mechanics (BM) to Quantum Field Theory (QFT) pointing out 
virtues and limits of these models, and secondly I will discuss whether 
or not they are interesting alternatives to the conventional QFT.
Since it is widely believed that BM cannot be extended to the realm of 
QFT in virtue of several no go theorems that exclude the possibility to 
have a particle ontology in relativistic quantum mechanics, I will show 
how this criticism misses the point.  The severe problems that BM 
encounters within the relativistic framework are discussed as well.
Finally, I will point out the necessity to have a clear ontology as a 
basic ingredient of a physical theory.