XXVI IFT Christmas Workshop
Program
Day 1: Wednesday, 16 December 2020 


Schedule  Speaker  Title  Slides  
15:00  16:15  Alessandra Buonanno  The Making of HighPrecision Gravitational Waves to Explore the Dark Universe  
16:15  17:30  George Efstathiou  The Hubble Tension  
17:30  17:45  Virtual Coffee Break  
17:45  19:00  Manfred Lindner  The XENON1T excess, interpretations and implications 
Day 2: Thursday, 17 December 2020 


Schedule  Speaker  Title  Slides  
15:00  16:15  Thomas SchwetzMangold  The fate of hints: recent developments in neutrino physics  
16:15  17:30  Jesse Thaler  Collider Physics and Machine Learning  
17:30  17:45  Virtual Coffee Break  
17:45  19:00  Netta Engelhardt  The Information Paradox in the Age of Holographic Entanglement Entropy 
Day 3: Friday, 18 December 2020 


Schedule  Speaker  Title  Slides  
15:00  16:15  Zohreh Davoudi  Toward quantum simulation of systems of relevance to nuclear and particle physics  
16:15  17:30  Pol FornDíaz  A superconducting Qbit as a universal approximant 


17:30  17:45  Virtual Coffee Break  
17:45  19:00  Nima ArkaniHamed  Spacetime, Quantum Mechanics and Positive Geometry at Infinity 

Abstracts/Topics:
Speaker (Affiliation): Nima ArkaniHamed (Institute for Advanced Study, Princeton)
Title: Spacetime, Quantum Mechanics and Positive Geometry at Infinity
Abstract: TBA
Speaker (Affiliation): Alessandra Buonanno (Max Planck Institute for Gravitational Physics)
Title: The Making of HighPrecision Gravitational Waves to Explore the Dark Universe
Abstract: The solution of the twobody problem in General Relativity has been crucial in observing gravitational waves from binary systems composed of black holes and neutron stars, and inferring their astrophysical, cosmological and gravitational properties. I will review the theoretical groundwork that has enabled these observations, and discuss recent theoretical advances aimed at predicting highly accurate waveform models for future detectors on the ground and in space. Finally, I will highlight some interesting observational findings obtained recently by the LIGO and Virgo detectors.
Speaker (Affiliation): Zohreh Davoudi (University of Maryland)
Title: Toward quantum simulation of systems of relevance to nuclear and particle physics
Abstract: A vibrant program has formed in recent years in various scientific disciplines to take advantage of nearterm and future quantumsimulation and quantumcomputing hardware to study complex quantum manybody systems, building upon the vision of Richard Feynman for quantum simulation. Such activities have recently started in nuclear and particle physics, hoping to bring new and powerful experimental and computational tools to eventually address a range of challenging problems in strongly interacting quantum field theories and nuclear manybody systems. In this talk, I first motivate the need for quantum simulation in nuclear physics by showcasing some of the state of the art in our classical simulations and discussing the existing challenges to move ahead. I will then review a number of important developments in quantum simulation, including proposals for simulating strongly interacting field theories with the ultimate goal of studying strong dynamics of quarks and gluons, and of nucleons. Some of the requirements for hardware technologies that are expected to enable both the analog simulations and the digital quantum computations of these problems will be enumerated, and an experimenttheory codevelopment program will be motivated with an emphasis on trappedion platforms.
Speaker (Affiliation): George Efstathiou (Kavli Institute for Cosmology, Cambridge)
Title: The Hubble Tension
Abstract: I will review the constraints on H_0 from the Planck CMB measurements and compare the best fit Planck model with recent results from ACTpol. The CMB value of H_0 is secure, yet is in tension with Cepheid based measurements of H_0. Although the CMB value is based on the Lambda CDM cosmology, there has been no compelling theoretical modification of the model that can explain the tension. I will therefore explore whether systematic errors may be affecting the Cepheid distance scale and if so, what must these errors look like.
Speaker (Affiliation): Netta Engelhardt (MIT)
Title: The Information Paradox in the Age of Holographic Entanglement Entropy
Abstract: The black hole information paradox — whether information escapes an evaporating black hole or not — remains one of the greatest unsolved mysteries of theoretical physics. The apparent conflict between validity of semiclassical gravity at low energies and unitarity of quantum mechanics has long been expected to find its resolution in the deep quantum gravity regime. Recent developments in the holographic dictionary and in particular its application to entanglement, however, have shown that a semiclassical analysis of gravitational physics has a hallmark feature of unitary evolution. I will describe this recent progress and discuss some potential new avenues for working towards a resolution of the information paradox.
Speaker (Affiliation): Pol FornDíaz (IFAE)
Title: A superconducting Qbit as a universal approximant
Abstract: A single qubit can approximate any bounded complex function as stored in the degrees of freedom defining the quantum state. This result is analogue to two known theorems ensuring approximations for functions, namely Fourier series and the Universal Approximation Theorem (UAT), that holds for neural networks with a large enough single, intermediate hidden layer. The single qubit circuit becomes more accurate as the independent function variable is reuploaded in an increasing number of gates, analogous to the classical methods that grow in accuracy with an increased number of intermediate steps. We further implement a onequbit approximant in a real superconducting qubit device consisting of a transmon qubit in a threedimensional cavity, explicitly showing how the ability to describe a set of functions improves with the depth of the quantum circuit.
Speaker (Affiliation): Manfred Lindner, (Max Planck Institute for Nuclear Physics, Heidelberg)
Title: The XENON1T excess
Abstract: The XENON1T experiment aims at detecting signatures of dark matter. The latest analysis showed, however, an unexpected excess of events with low recoil energy. The talk will cover in detail how the signal is obtained and different interpretations of this excess. The signal might point to new physics and several theoretical directions and their implications for future measurements and other experiments will be discussed.
Speaker (Affiliation): Thomas SchwetzMangold (Karlsruhe Institute of Technology)
Title: The fate of hints: recent developments in neutrino physics
Abstract: Finite neutrino mass points to new physics beyond the Standard Model. In this talk I give an overview over recent results in neutrino physics, including the results of a combined analysis of latest neutrino oscillation data. We comment on the implications of this years results for the type of neutrino mass ordering (normal versus inverted) and on the status of leptonic CP violation within the minimal 3flavour framework. I review the status of absolute neutrino mass searches and searches for leptonnumber violation. I will briefly discuss some examples for searches for more exotic physics in the neutrino sector, including sterile neutrinos. The guidline of my talk will be various "hints" for standard as well as nonstandard physics, which have been around for some time in neutrino data, and their fate due to recent developements.
Speaker (Affiliation): Jesse Thaler (MIT)
Title: Collider Physics and Machine Learning
Abstract: Modern machine learning has had an outsized impact on many scientific fields, and particle physics is no exception. What is special about particle physics, though, is the vast amount of theoretical and experimental knowledge that we already have about many problems in the field. In this talk, I draw on examples from collider phenomenology and quantum chromodynamics to highlight the fascinating interplay between theoretical principles and machine learning strategies.
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