BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Nicolas C. Menicucci (Royal Melbourne Institute of Technology) DTSTART:20230502T070000Z DTEND:20230502T090000Z DTSTAMP:20260419T092957Z UID:3cqfs/4 DESCRIPTION:Title: Ta chyonic media in sonic relativity\nby Nicolas C. Menicucci (Royal Melb ourne Institute of Technology) as part of Tricontinental Quantum Fundament als Seminar\n\n\nAbstract\nIn sonic models of special relativity\, the fac t that the sonic medium violates (ordinary) Lorentz symmetry is apparent t o observers external to the sonic medium but not to a class of observers e xisting within the medium itself. We show that the situation is symmetric: internal observers will judge physics in the external laboratory to viola te their own sonic Lorentz symmetries. We therefore treat all observers on an equal footing such that each is able to retain a commitment to their o wn Lorentz symmetries.\n\nWe then generalize beyond the case of subsystem- environment decompositions to situations in which there exist multiple pho non fields\, all obeying Lorentz symmetries but with different invariant s peeds. In such cases\, we argue that all observers have freedom to choose which field is symmetry preserving\, and so -- in a certain precise sense -- which other fields are perceived as having an 'ether.' This choice is i nfluenced -- but not determined -- by a desire for simplicity in the descr iption of physical laws.\n\nSending information faster than sound serves a s a model of tachyonic signalling to a distant receiver. Immutable causali ty of the laboratory setup when perceived externally to a sonic medium man ifests internally through the confinement of the tachyons to an apparent e ther (with a rest frame)\, which we call a 'tachyonic medium\,' thereby pr eventing tachyonic exchange from emulating the scenario of a round-trip si gnal travelling into an observer's past causal cone. The assignment of son ic-Lorentz-violating effects to fields that obey 'photonic' Lorentz symmet ries thus ensures that causality associated with the 'sonic' Lorentz symme tries is preserved.\n LOCATION:https://researchseminars.org/talk/3cqfs/4/ END:VEVENT END:VCALENDAR