BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Itamar Procaccia (Weizmann Institute of Science) DTSTART:20211013T160000Z DTEND:20211013T170000Z DTSTAMP:20260404T111006Z UID:IIPSeminar/1 DESCRIPTION:Title: Anomalous Elasticity and Plastic Screening in Amorphous Solids\nby Itamar Procaccia (Weizmann Institute of Science) as part of Virtual Seminar of the International Institute of Physics\n\n\nAbstract\nIn this lecture I will argue that elasticity theory needs to be fundamentally chan ged in order to deal with amorphous solids. In a recent paper [Phys. Rev. E 104\, 024904] we showed that mechanical strains in amorphous solids are screened via the formation of plastic events that are typically quadrupol ar in nature. At low densities of quadrupoles the screening effect is rem iniscent of the role of dipoles in dielectrics\, while the effect at high density has no immediate electrostatic analog\, and is expected to change qualitatively the mechanical response\, as seen for example in the displac ement \nfield. The phenomenon is akin to a Kosterlitz-Thouless transition as will be explained in this lecture. I will show that high-density screen ing results in undulating displacement \nfields that strictly deviate from elasticity theory. Theoretical analysis\, experimental measurements and n umerical simulations of frictional granular amorphous assemblies are in ag reement with each other and provide a strong support for the theory.\n LOCATION:https://stable.researchseminars.org/talk/IIPSeminar/1/ END:VEVENT BEGIN:VEVENT SUMMARY:Antonio Duarte Pereira (Federal Fluminense University) DTSTART:20211020T160000Z DTEND:20211020T170000Z DTSTAMP:20260404T111006Z UID:IIPSeminar/2 DESCRIPTION:Title: Spacetime and matter under the microscope\nby Antonio Duarte Pereira (Federal Fluminense University) as part of Virtual Seminar of the International Institute of Physics\n\nAbstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/IIPSeminar/2/ END:VEVENT BEGIN:VEVENT SUMMARY:Thiago Tomei (UNESP) DTSTART:20211103T160000Z DTEND:20211103T170000Z DTSTAMP:20260404T111006Z UID:IIPSeminar/3 DESCRIPTION:Title: BSM and Dark Matter searches in Colliders\nby Thiago Tomei ( UNESP) as part of Virtual Seminar of the International Institute of Physic s\n\n\nAbstract\nThe search for physics beyond the standard model remains one of the main directives of the LHC experiments. One possible direction for this search is the understanding of the "dark matter" phenomena\, a se t of astronomical and cosmological evidences that seem to point in the dir ection of a hitherto unknown kind of invisible matter. The quest for dark matter profits from the complementarity between direct/indirect detection and collider experiments. In this talk we will quickly introduce dark matt er\, the LHC and the general-purpose LHC experiments. We will then underst and how to search for dark matter in a hadron collider\, and finish with t he latest results on dark matter searches from the LHC.\n LOCATION:https://stable.researchseminars.org/talk/IIPSeminar/3/ END:VEVENT BEGIN:VEVENT SUMMARY:Ady Stern (Weizmann Institute of Science) DTSTART:20211110T160000Z DTEND:20211110T170000Z DTSTAMP:20260404T111006Z UID:IIPSeminar/4 DESCRIPTION:Title: Spread and erase - How electron hydrodynamics can eliminate the Landauer-Sharvin resistance\nby Ady Stern (Weizmann Institute of Scien ce) as part of Virtual Seminar of the International Institute of Physics\n \n\nAbstract\nIt has long been realized that even a perfectly clean electr onic system harbors a Landauer-Sharvin resistance\, inversely proportional to the number of its conduction channels. This resistance is usually asso ciated with voltage drops on the system's contacts to an external circuit. Recent theories have shown that hydrodynamic effects can reduce this resi stance\, raising the question of the lower bound of resistance of hydrodyn amic electrons. Here we show that by a proper choice of device geometry\, it is possible to spread the Landauer-Sharvin resistance throughout the bu lk of the system\, allowing its complete elimination by electron hydrodyna mics. We trace the effect to the dynamics of electrons flowing in channels that terminate within the sample.\n LOCATION:https://stable.researchseminars.org/talk/IIPSeminar/4/ END:VEVENT BEGIN:VEVENT SUMMARY:Veronika Baumann (Institute for Quantum Optics and Quantum Informa tion) DTSTART:20211117T160000Z DTEND:20211117T170000Z DTSTAMP:20260404T111006Z UID:IIPSeminar/5 DESCRIPTION:Title: Observers in superposition and the quantum measurement problem\nby Veronika Baumann (Institute for Quantum Optics and Quantum Informat ion) as part of Virtual Seminar of the International Institute of Physics\ n\n\nAbstract\nThe quantum measurement problem is one of the oldest concep tual problems of quantum theory and based on the fact that (standard) quan tum theory comprises two different dynamics\, namely the collapse of the w ave function\, which without any ontological commitment means the applicat ion of the state-update rule\, and unitary evolution. Quantum theory\, how ever\, does not tell us when to use which dynamics\, meaning that it does not specify what qualifies some interactions as measurements\, but not oth ers. \n\nWigner’s-friend experiments consider observations of observers in order to illustrate the measurement problem. They comprise observers — friends — who measure quantum systems\, as well as so-called superob servers – Wigners– who perform joint measurements on the quantum syste ms\, the friends and potentially other relevant degrees of freedom. The fr iends describe their interactions with the respective quantum systems as m easurements and\, therefore\, apply the state-update rule\, while the Wign ers describe the same interactions unitarily.\n\nIn recent years new propo sals involving Winger’s friend experiments have been used to devise argu ments against the consistency of quantum theory and the existence of objec tive\, observer-independent facts\, which sparked renewed debate in the qu antum-foundations community. We made a clear distinction between the forma lism and the interpretations of quantum theory and showed that there are a ctually two inequivalent quantum formalisms. If different agents in a Wign er’s-friend experiment use different formal descriptions for a quantum m easurement\, they arrive at contradicting statements. This\, however\, bec omes manifest only if there are classical records of these statements that can be compared at some point.\n LOCATION:https://stable.researchseminars.org/talk/IIPSeminar/5/ END:VEVENT BEGIN:VEVENT SUMMARY:Michael Berry (University of Bristol) DTSTART:20211124T160000Z DTEND:20211124T170000Z DTSTAMP:20260404T111006Z UID:IIPSeminar/6 DESCRIPTION:Title: Divergent series: from Thomas Bayes’s bewilderment to today’ s resurgence via the rainbow\nby Michael Berry (University of Bristol) as part of Virtual Seminar of the International Institute of Physics\n\nA bstract: TBA\n LOCATION:https://stable.researchseminars.org/talk/IIPSeminar/6/ END:VEVENT BEGIN:VEVENT SUMMARY:Rodrigo Pereira (International Institute of Physics) DTSTART:20211027T160000Z DTEND:20211027T170000Z DTSTAMP:20260404T111006Z UID:IIPSeminar/7 DESCRIPTION:Title: Majorana fermions bound to line defects in Kitaev spin liquids\nby Rodrigo Pereira (International Institute of Physics) as part of Vir tual Seminar of the International Institute of Physics\n\n\nAbstract\nThe field-induced Kitaev spin liquid is a strongly correlated topological phas e which may have been realized in the layered material alpha-RuCl3. It is characterized by the presence of gapped non-Abelian anyon excitations in t he bulk and gapless chiral Majorana modes at the edges. In this talk I wil l show that gapless one-dimensional modes can also survive in the bulk of the Kitaev spin liquid when they are bound to line defects at which the ex change interaction falls below a critical value. Treating the weak interac tion at the line defect within a mean-field approximation\, we determine t he critical interaction strength as a function of the external magnetic fi eld. In the gapless regime\, we use the low-energy effective field theory to calculate the spin-lattice relaxation rate for a spin near the defect. I will also discuss the relevance of these results to nuclear magnetic res onance experiments that claimed to have observed gapless excitations in th e putative spin liquid phase of alpha-RuCl3.\n LOCATION:https://stable.researchseminars.org/talk/IIPSeminar/7/ END:VEVENT END:VCALENDAR