El profesor José Bernabéu (Departamento de Física Teórica de la Universidad de Valencia) ofrece la conferencia «Time vs reality: Entanglement in particle physics», en el marco del ciclo Fronteras de la Física.
Resumen:
Entanglement in particle anti-particle systems, like K0-K0bar and B0-B0bar in charge conjugation C = -, offers several novelties not present in other fields. This includes the mixing between the partners, charge-parity CP violation – either in the mixing, the interference between mixing and decay or the decay- and above all a non-trivial time evolution of the system. Besides the study of the time history of the system since the production to its fate, with the tag of the living partner and the quantum filtering of the first-decayed state, a way to inquire into the states at entanglement times t1 before the first decay appears.
A novel surviving quantum correlation-in-time emerges from the observation of the second decay at time t2 > t1, when the system is no longer entangled, to the post-tag of the past- decayed state before its decay when the system was entangled. The two correlations, from past to future and from future to past, are asymmetric and the second adds the surprising result that the past-decayed state depends on the future observation time t2. This dependence is fully observable from the t1-distribution of events for two identical observations at distinct times t2 and can be quantified for the K0-K0bar system, where the KLOE-2 collaboration at DAPHNE has presented preliminary results. Neither in classical nor in quantum mechanics time is an observable, it is a parameter describing the definite evolving reality. Past states depending on future observation times call for a novel role of time in quantum mechanics and establish a lack of instant realism.
The two correlations are most rewarding as a tool to bypass existing no-go arguments for single unstable particles. I shall first discuss the conceptual basis for a direct test of Time Reversal – and CPT – in the Delta t = t2-t1 evolution of the living partner in the B0-B0bar system. The observation of Time-Reversal-Violation by the BABAR experiment followed these ideas. An asymmetry «independent of the decay products» allows the reversal of meson states in Delta t.
CP violation and the non-orthogonality of the KS,L states of definite time evolution in the K0- K0bar system preclude their tag on an event-by-event basis. The novel correlation-in-time from future to past establishes for the first time (after 60 years of rare KL decays) the condition to tag a KS-beam with any desired purity. This fact opens an entirely new field in particle physics.
- Fecha: Viernes 22 de Septiembre de 2023
- Lugar: Facultad de Ciencias. Aula F-01.
La conferencia también podrá seguirse ONLINE en el siguiente enlace: https://meet.google.com/jhs-eqvg-tdd - Horario: 12:30 h
- Organizan: Grupo de Física de Altas Energías e Instituto Carlos I de Física Teórica y Computacional (UGR)
- Más información: https://ic1.es/index.php/actividades/fronteras-de-la-fisica/