BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Pablo Bueno (Instituto Balseiro\, Bariloche) DTSTART:20201021T190000Z DTEND:20201021T201500Z DTSTAMP:20260423T035609Z UID:IFQ/7 DESCRIPTION:Title: Refl ected entropy\, free fields and symmetries\nby Pablo Bueno (Instituto Balseiro\, Bariloche) as part of It from Qubit\n\n\nAbstract\nA well-defin ed notion of von Neumann entropy associated to pairs of spatial subregions has been recently proposed both in the holographic context and for genera l QFTs. I will show that in the case of Gaussian systems ---and similarly to the entanglement entropy (EE)--- this "reflected entropy” can be obta ined in terms of correlation functions of the fields. In particular\, I wi ll present general formulas valid for free scalars and fermions in arbitra ry dimensions. I will apply the results to various free theories in 1+1 an d 2+1 dimensions\, verifying that the conjectural monotonicity property $R (A\,BC)\\geq R(A\,B)$ and the general inequality $R(A\,B)\\geq I(A\,B)$ ho ld in all cases. The results obtained suggest that for general regions cha racterized by length-scales $L_A\\sim L_B \\sim L$ and separated a distanc e $\\ell$\, the reflected entropy in the large-separation regime ($x\\equi v L/\\ell \\ll 1$) is related to the mutual information by: $R(x) \\sim −I(x) \\log x$ for general CFTs in arbitrary dimensions. Finally\, I wil l argue that the notion of reflected entropy can be canonically generalize d in a way which is particularly suitable for theories obtained by restric ting the full algebra of operators to those which are neutral under global symmetry groups. A key role in the discussion is played by type-I von Neu mann algebras\, which differ from the usual type-III algebras associated t o spatial subregions in QFT. I will perform various explicit comparisons b etween both types of algebras.\n LOCATION:https://researchseminars.org/talk/IFQ/7/ END:VEVENT END:VCALENDAR