"Some logical questionings from quantum theories"
14:00 hs - Décio Krause
Department of Philosophy Federal University of Santa Catarina and Graduate Program in Logic and Metaphysics Federal University of Rio de Janeiro, Brasil.
Resumen:
Quantum theories (both quantum mechanics and quantum field theories) bring several puzzles to classical logic, which base almost all books on these theories. In this talk, I have chosen some topics on which I have worked about and which in most cases go unnoticed. Among them, I list the following ones: 1. the prominence of the notion of indiscernibility (or indistinguishability) over identity. This last one, if taken as prescribed by standard logic, implies that any two things are different in a strong sense, namely, there exists a property owned by one but not the other, which goes against the existence of bosons in the same quantum state and fermions in entangled states (where we cannot know ‘which is which’). 2. the ‘quantum logical connectives’ depart from their ‘classical’ relatives. 3. the notion of set of classical theories, understood as collections of discernible objects, depart from collection of indiscernible quantum systems. 4. the topology of ‘quantum space’ should not have the Hausdorff property, since there are no completely separate wave-functions, mainly in the case of entanglement. These are some of the questions which should be taken into account in philosophical and foundational studies of quantum theories.
"Sistemas fermiónicos bajo decoherencia colectiva de entrelazamiento"
14:40 hs - Diego G. Bussandri
Instituto de Física de La Plata - CONICET, La Plata, Argentina.
Resumen:
Analizaremos la dinámica del entrelazamiento bajo decoherencia de un sistema de dos fermiones idénticos con espín 3/2, producto de un entorno bosónico global. Tal evolución, y según el estado inicial del sistema, implica tres tipos de comportamientos cualitativamente diferentes: i) régimen invariante: se identifican estados iniciales que pertenecen a un subespacio libre de decoherencia (DFS), que mantienen invariante su entrelazamiento y coherencia a lo largo de la evolución; ii) decaimiento exponencial: correspondiente a estados iniciales ortogonales al DFS, y evolucionan hacia estados cuyo entrelazamiento y coherencia disminuyen exponencialmente; iii) decaimiento súbito del entrelazamiento: corresponde a estados iniciales que tienen cierta superposición con el DFS y exhiben una dinámica con mayor complejidad que a su vez conduce a un decaimiento súbito del entrelazamiento fermiónico, mientras que la coherencia decae exponencialmente.
15:20 hs - Recreo
"Interacción fuerte y distinguibilidad en trampas armónicas"
15:30 hs - Johanna Fuks
Departamento de Fisica, Universidad de Buenos Aires (UBA) - CONICET, Buenos Aires, Argentina.
Resumen:
We explore the potential of twisted light as a tool to unveil many-body effects in parabolically confined systems. According to the Generalized Kohn Theorem, the dipole response of such a multiparticle system to a spatially homogeneous probe is indistinguishable from the response of a system of non-interacting particles. Twisted light however can excite internal degrees of freedom, resulting in the appearance of new peaks in the even multipole spectrum which are not present when the probe is a plane wave. We also demonstrate the ability of the proposed twisted light probe to capture the transition of interacting fermions into a strongly correlated regime in a one-dimensional harmonic trap. We report that by suitable choice of the probe’s parameters, the transition into a strongly correlated phase manifests itself as an approach and ultimate superposition of peaks in the second order quadrupole response. These features, observed in exact calculations for two electrons, are reproduced in adiabatic Time Dependent Density Functional Theory simulations.
16:10 hs - Mesa de discusión y cierre