BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Alvaro Martin Alhambra (MPI-Quantenoptick. Garching) DTSTART:20210114T150000Z DTEND:20210114T160000Z DTSTAMP:20260423T003250Z UID:IFTWeb/26 DESCRIPTION:Title: Quantum thermal states on the lattice: correlations\, area laws and tensor network representations\nby Alvaro Martin Alhambra (MPI-Quantenoptick . Garching) as part of IFT-Madrid Webinars\n\n\nAbstract\nIn the past coup le of decades\, one of the biggest triumphs of quantum information theory has been the characterization of correlations of ground states of quantum many-body systems. This usually takes the form of area laws for the entang lement entropy\, which can be rigorously linked to the efficient classical simulability of ground states. A similar intuition applies to thermal sta tes\, which are known to obey an area law for the quantum mutual informati on. Here\, we will present the tightest area laws known for quantum therma l states on lattices\, with an improved dependence on the temperature. The se involve the mutual information\, as well as other information-theoretic measures of correlations\, such as the entanglement of purification. Whil e the direct connection between thermal area laws and simulability is stil l unknown\, we show how the same techniques that lead to improved area law s also lead to provably efficient tensor network algorithms for thermal st ates. In doing so\, we provide the first rigorous quasilinear-time algorit hm for one-dimensional models\, which closely matches what is found in heu ristic numerical approaches.\n LOCATION:https://researchseminars.org/talk/IFTWeb/26/ END:VEVENT END:VCALENDAR