[PhilPhys] Lisbon Philosophy of Physics Seminars: Tomasz Bigaj (December 21 on Zoom)

[Andrea Oldofredi]

Dear List Members,

On Wednesday December 21 Tomasz Bigaj (University of Warsaw) will give a
talk at the Lisbon Philosophy of Physics Seminars titled "*Two methods of
individuating quantum particles*" (abstract below).

These events are organized in the context of the activities of the LanCog
Research Group <https://cful.letras.ulisboa.pt/lancog/> at the Centre of
Philosophy of the University of Lisbon, and they will focus on the
foundations of quantum and spacetime physics.

The meeting will be held on Zoom (17:00-19:00 CET). If you have not
registered yet, you can do so here
<https://docs.google.com/forms/d/1pe9-CUZwKFA_uS0j-wD7bRQatIO-SdzxBqKlmkM6XOY/edit?usp=drive_web>
.

You can address any question to Andrea Oldofredi (
aoldofredi at letras.ulisboa.pt).

ABSTRACT:
In this talk I will discuss the possibility of individuating particles of
the same type with the help of some physical properties. The standard
quantum theory of many particles requires that the states of groups of
identical particles should have specific symmetry properties (they should
be symmetric for bosons and antisymmetric for fermions). From the
Symmetrization Postulate it is possible to derive the conclusion that the
expectation values of all measurable properties are identical for all
particles involved. This is commonly seen as invalidating the Principle of
the Identity of Indiscernibles (PII). However, the above-mentioned
derivation is based on an in-principle illegitimate use of non-symmetric
operators as representing properties of individual particles. I will
present and discuss an alternative formalization of individualized
properties for the components of composite systems, which is based entirely
on symmetric projectors. The alternative method of individualization
implies that identical fermions are always discerned by their properties,
while identical bosons may still occupy states that violate PII. I will
further repel some objections to the proposed approach, and I will point
out its main difficulty, which is the existence of a surprising
multiplicity of alternative and mutually incompatible individuations.

Best regards,

Andrea Oldofredi
----------

Dr. Andrea Oldofredi

Postdoc FCT

Internet Resources:
https://unil.academia.edu/AndreaOldofredi
https://www.researchgate.net/profile/Andrea_Oldofredi

Mailing Address:
University of Lisbon
Centre of Philosophy
Alameda da Universidade, 1600-214, Lisbon
Portugal
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