Calendar
- 22March 22, 2020No events
- 23March 23, 2020
CMSA Mathematical Physics Seminar: Bit Threads: Understanding Gravitation from Quantum Entanglement
via Zoom Video Conferencing: https://harvard.zoom.us/j/738333299
The AdS/CFT correspondence stipulates that gravitational evolution in a bulk spacetime is dual to a boundary description that has no gravity. In the AdS/CFT picture the bulk spacetime evolves gravitationally against an anti-de Sitter space background, and the boundary dual theory is a conformal gauge theory in a spacetime of one dimension less. Recent insights by Ryu and Takayanagi have conjectured that quantum entangled boundary states quantitatively give rise to geometry in the bulk. They do so by explicitly referring to “minimal surfaces” in the bulk, connecting them to the entropy of a related area in the boundary. I will present a conceptually and technically powerful complementary holographic entanglement picture, reformulating Ryu–Takayanagi to no longer refer to minimal surfaces, and suggesting a new way to think about the holographic principle and the connection between spacetime gravitation and information. I will introduce the idea of bit threads, and show how they can be used for fun and profit.
- 24March 24, 2020
QAOA: Landscape Independence and the Sherrington-Kirkpatrick Models
via Zoom Video Conferencing: https://harvard.zoom.us/j/881015355
- 25March 25, 2020
CMSA Quantum Matter/Quantum Field Theory Seminar: Fluctuating pair density wave in cuprates
via Zoom Video Conferencing: TBA
Recent high-field low-temperature data shed new light on the mysterious pseudogap phase in cuprates. I will introduce a simple way
to synthesize the low-temperature data, the charge density wave, and the previous ARPES and optical data. In the meantime, I will discuss
the general problem of how fluctuating superconducting order changes the fermion spectrum and other response functions.Sato-Tate groups of abelian threefolds
via Zoom Video Conferencing: https://harvard.zoom.us/j/136830668
The Sato-Tate group of an abelian variety A of dimension g defined over a number field is a compact real Lie subgroup of the unitary
simplectic group of degree 2g that conjecturally governs the limiting distribution of the normalized Frobenius elements acting on the Tate module
of A. In previous joint work with Kedlaya, Rotger and Sutherland, it was shown that there are 52 such subgroups (up to conjugacy) that occur as
Sato-Tate groups of abelian surfaces over number fields. In this talk I will present several aspects of the classification of the 410 subgroups (up
to conjugacy) of the unitary symplectic group of degree 6 that occur as the Sato-Tate groups of abelian threefolds over number fields. This is a joint
work with Kiran Kedlaya and Andrew Sutherland.Absolute period leaves and the Arnoux—Yoccoz example in genus 3
Seminar will meet via Zoom Video Conferencing: https://harvard.zoom.us/j/972495373
- 26March 26, 2020No events
- 27March 27, 2020
The spacetime positive mass theorem and path connectedness of initial data sets
via Zoom Video Conferencing: https://harvard.zoom.us/j/635180669
The purpose of this talk is twofold: First we present a new proof of the spacetime positive mass theorem (joint with Demetre Kazaras and Marcus Khuri); second we discuss some new results about the topology of initial data sets (joint with Martin Lesourd).The spacetime positive mass theorem that the mass of an initial data set is non-negative with equality if and only if the initial data set arises as subset of Minkowski space. This result has first been proven by Schoen and Yau using Jang’s equation. There are further proofs by Witten using spinors and by Eichmair, Huang, Lee and Schoen using MOTS. Our proof uses Stern’s integral formula technique and also leads to a new explicit lower bound of the mass which is even valid when the dominant energy condition is not satisfied.A central conjecture in mathematical relativity is the final state conjecture which states that initial data sets will eventually approach Kerr black holes. In particular, this would imply that the space of initial data sets is path connected. Building upon the work of Marques and using deep and beautiful results of Carlotto and Li, we show that indeed the space of initial data set with compact trapped interior boundary is path connected. - 28March 28, 2020No events