Anand Natarajan (Quantum Information Theory Search) “Interactive proofs and quantum entanglement” Monday, March 23, 2020 1:15 – 2:15pm VIRTUAL TALK - Click here to join talk: https://harvard.zoom.us/j/219078028 This talk will be held via Zoom and we hope you will be able to participate remotely! The public Zoom link can be used to sign into the live talk from your office, home, etc. Please note that these talks will be recorded. Please also review the below guidelines for accessing and participating in the Zoom talk. Topic: Anand Natarajan - Faculty Candidate Time: Mar 23, 2020 01:00 PM Eastern Time (US and Canada) Join Zoom meeting https://harvard.zoom.us/j/219078028 Join by telephone (use any number to dial in) +1 312 626 6799 +1 929 436 2866 +1 253 215 8782 +1 301 715 8592 +1 346 248 7799 +1 669 900 6833 International numbers available: https://harvard.zoom.us/u/acfXWMMcSC One tap mobile: +13126266799,,219078028# US (Chicago) Join by SIP conference room system Meeting ID: 219 078 028 219078028@zoomcrc.com<mailto:219078028@zoomcrc.com> Ahead of the talk time, please: * Download Zoom<https://harvard.service-now.com/ithelp?id=kb_article&sys_id=5d3… and test your log-in. * Log in and join the meeting<https://harvard.zoom.us/j/680480385> on time. * Make sure your video is turned off. * Use headphones so as not to distract others with whom you share a space. * You should be muted, but please check this upon entering. * At any time during the talk, typed comments or questions can be directed to the moderator via Zoom’s chat function<https://support.zoom.us/hc/en-us/articles/203650445-In-Meeting-Chat>. Messages sent this way will only be visible to the moderator (and facilitator) and will be addressed as opportunity allows. * At the end of the talk, there will be a question period. Use the “raise your hand” feature to enter the question queue, and wait for a prompt to unmute your microphone. The moderator will select questions from the queue of “raised hands” as time allows. Title: Interactive proofs and quantum entanglement Abstract: Interactive proof systems are a classic idea in theoretical computer science, and have led to fundamental advances in complexity theory (hardness of approximation and the PCP theorem) and cryptography. Remarkably, in quantum information, interactive proof systems with multiple provers have become an important tool for studying quantum entanglement, extending the pioneering work of Bell in the 1960s. In this talk I will discuss recent progress in characterizing the power of the complexity class MIP* of such proof systems where the provers share entanglement. In addition to revealing an area of quantum complexity theory that is strikingly different from its classical counterpart, this work has led to new schemes for delegating quantum computations to untrusted servers, as well as to consequences for Tsirelson’s problem in mathematic physics, and the Connes embedding problem in operator algebras. At the heart of this work are new protocols that use classical PCP techniques together with the rules of quantum mechanics to let a classical client precisely control an untrusted quantum server.