CPT

Calendar of Physics Talks Vienna

Mirror dual Elliptic fibrations and F-theory
Speaker:Paul Oehlmann (Uppsala University)
Abstract:In this talk we discuss pairs of mirror dual elliptic n-folds. We show that under certain conditions mirror duality can factor into a fiber and base action, which yields mirror dual fibrations. For threefolds this allows us to study two F-theory compactifications where Higgs and tensor branches are exchanged. We give several examples and workout the exact base and fiber dictionary and further study (mirror dual) Higgs and tensor branch transitions. We then apply those those results to compute Higgs branches of 4D, N=2 rank one SCFTs.
Date: Tue, 23.11.2021
Time: 14:00
Duration: 60 min
Location:Zoom https://univienna.zoom.us/j/95630887425?pwd=UHNrSjc1SmlXWFFnRTlUOHoranlYQT09 ID meeting: 956 3088 7425 Passcode: 495059
Contact:S. Fredenhagen, D. Grumiller, E. Battista

Some Challenges to the Simulation of Radiation Effects in the Binary Collision Approximation
Speaker:Gerhard Hobler (Institut für Festkörperelektronik, Forschungsbereich Nanoelektronische Bauelemente TU Wien)
Abstract:The simulation of radiation effects in the binary collision approximation (BCA) has been well established for many decades, exemplified by the success of the SRIM/TRIM software. While limitations of the BCA are well known, their ease of use and computational efficiency compared to molecular dynamics simulations will secure them an important role in radiation effects research in the foreseeable future. In this talk, I will discuss some of the challenges I have faced in recent years in doing simulations with my BCA code IMSIL. In particular, I will elaborate on crystal direction dependent sputtering and on topography simulation including radiation induced viscous flow.
Date: Tue, 23.11.2021
Time: 16:00
Location:TU Wien, Institut für Angewandte Physik, E134 1040 Wien, Wiedner Hauptstraße 8-10 Yellow Tower „B“, 5th floor, SEM.R. DB gelb 05 B
Contact:Univ.Prof.Dr. Friedrich Aumayr

Precise predictions at the LHC with GENEVA
Speaker:Alessandro Broggio (University of Milan, Bicocca)
Abstract:In this talk I will first discuss the main features of the GENEVA Monte Carlo framework.After that, as an application, I will present a new NNLO calculation for the photon pair production process at the LHC where the 0-jettiness resolution variable is resummed to NNLL' accuracy by using soft-collinear effective theory methods.Then I will discuss the implementation of this process within the Geneva Monte Carlo focusing on the photon isolation algorithm to remove final-state QED singularities. The partonic events are then showered and hadronised using Pythia8 while retaining the NNLO QCD accuracy for observables which are inclusive over the additional radiation.In the second part of the talk,I will present the theoretical framework and the numerical results for the 0-jettiness resummation for the top-quark pair production process at the LHC,which is the basis for a future Monte Carlo . . .
Date: Tue, 23.11.2021
Time: 16:00
Duration: 60 min
Location: Zoom link to attend remotely is 
 https://univienna.zoom.us/j/93427906843?pwd=YjhSejdUVW16QjVQYUh5TVNSNFNhQT09 Meeting ID: 934 2790 6843 Passcode: 073703
Contact:A. Hoang, M. Procura

Physics with Antihydrogen
Speaker:Prof. Dr. Mike Charlton (Physics Department, Faculty of Science and Engineering, Swansea University)
Abstract:The formation, capture and interrogation of antihydrogen atoms has been pioneered over the last two decades or so. Recently this has included observation and characterization of the 1S-2S­ two-photon transition and use of the 1S-2P transition to effect laser-cooling of a trapped sample of the anti-atoms. Aspects of these advances will be described, as will some of the challenges along the way. We will discuss the physics motivations for undertaking such experiments. We will also describe the results of simulations of positron-antiproton mixing to form antihydrogen, including in a beam-like configuration, and a method to produce an antihydrogen beam using a travelling optical lattice. We will conclude with some speculations on the possibilities for antihydrogen chemistry. (see also: https://indico.cern.ch/event/1091223/)
Date: Wed, 24.11.2021
Time: 16:00
Duration: 60 min
Location:Webinar: request zoom-link by sending an email to martin.simon at oeaw.ac.at by 23.Nov. 16:00
Contact:Prof. Dr. Eberhard Widmann, Dr. Martin Simon

Continuous Gaussian Measurement in the free Boson CFT: An exactly solvable mode
Speaker:Yuri Minoguchi (TU Wien)
Abstract:Hybrid evolution protocols, composed of unitary dynamics and repeated, continuous or projective measurements, give rise to new, intriguing quantum phenomena, including entanglement phase transitions and unconventional conformal invariance. We introduce bosonic Gaussian measurements, which consist of the continuous observation of linear boson operators, and a free Hamiltonian evolution. The Gaussian evolution is then uniquely characterized by the system's covariance matrix, which, despite the stochastic nature of the hybrid protocol, obeys a deterministic, nonlinear evolution equation. The stationary state is exact and unique, and in many cases analytically solvable. Within this framework, we then consider an elementary model for quantum criticality, the free boson conformal field theory, and investigate in which way criticality is modified under a hybrid evolution. Depending on the measu
Date: Wed, 24.11.2021
Time: 16:15
Duration: 45 min
Location:https://tuwien.zoom.us/j/99712909944?pwd=dmlybGJYa2tTUWdFQlNNRmJ6YWx3dz09
Contact:Peter Rabl

Thermodynamics of AdS black holes: Critical behaviour of the central charge
Speaker: Wan Cong (Vienna)
Abstract:Black holes have been accepted as thermodynamic systems ever since Hawking’s discovery of black hole radiation.The thermodynamic phase space of AdS black holes has been extended to include a P-V term in[1]. By studying the equation of state of AdS black holes in this extended phase space, many interesting phase transitions were found;a prominent example is the Van der Waals like small-to-large phase transition of charged AdS black holes which takes place below a critical pressure[2]. Recently,Visser reconsidered the situation in the context of holography [3].While the natural unit G=1 was kept in previous studies,Visser argued that considering variations of G is necessary to achieve a duality between the bulk and boundary thermodynamic first laws.I will briefly review his argument,and rewrite the bulk first law in a new form containing both variations of P and C,the central charge . . .
Date: Thu, 25.11.2021
Time: 14:00
Duration: 60 min
Location:ZOOM https://univienna.zoom.us/j/6540036841?pwd=SytyVkZJZzNyRG9lMm13ejlHeHRRUT09
Contact:P. Chrusciel, D. Fajman

An application of error correction codes in physics
Speaker:Abhiram Kidambi (Kavli IPMU)
Abstract: On the interface of finite group theory, lattice theory and coding theory sits a concept on which relies most of modern technology: Error correction codes. These codes are simple mathematical logical operations to determine if any string of information has been transmitted/received incorrectly, and how they said error can be fixed. However, through breakthroughs in string theory and quantum field theory, in particular anomaly cancellation, these topics have also become part of physics. In this chalk talk, I will explain - what error correction codes are - what codes over fields of characteristic three are - how they relate to elliptic genera of N=1 quantum field theories.
Date: Thu, 25.11.2021
Time: 16:30
Duration: 60 min
Location:Seminar room 10th floor (yellow tower)
Contact:Laura Donnay, Iva Lovrekovic

Horizon violations in quantum physics
Speaker:Ivan Kukuljan (MPQ, DE )
Abstract:Spreading of correlations is one of the key aspects of quantum nonequilibrium physics. For a long time, it has been believed that starting with an initial state with short range correlation functions, these correlations will spread inside the causal horizon with a nonequilibrium time evolution. The intuition was that the correlations spread by pairs of entangled quasiparticles generated in initially correlated regions. We have recently demonstrated that this picture is incomplete and much more intricate effects can occur in quantum field theories with a topological nature. Particularly, we have shown that taking the system out of equilibrium by a quantum quench generates entanglement of topological excitations resulting in infinite range correlations in the system. In the talk, I will present this effect and explain the underlying mechanism.
Date: Fri, 26.11.2021
Time: 10:00
Duration: 45 min
Location:Hörsaal ATI/ https://tuwien.zoom.us/j/99712909944?pwd=dmlybGJYa2tTUWdFQlNNRmJ6YWx3dz09
Contact:Jörg Schmiedmayer

Aspects of threshold resummation at next-to-leading power
Speaker: Leonardo Vernazza (INFN)
Abstract:Collider observables involving heavy states are subject to large logarithmic terms near threshold, which must be summed to all orders in perturbation theory to obtain sensible results. Relatively recently, this resummation has been extended to next-to-leading power in the threshold variable, using diagrammatic and effective field theory techniques.In this talk I will present the state of the art and discuss current limitations, related to the appearance of divergent convolutions, which prevent the application of factorization methods known from leading power resummation. To this end I will focus on partonic channels that turn on only at next-to-leading power, in deep inelastic scattering, Drell-Yan and Higgs boson production. I will illustrate how the study of these channels gives us a better understanding of the origin of such singularities. Furthermore, I will show that an explicit . .
Date: Fri, 26.11.2021
Time: 16:00
Duration: 60 min
Location:ZOOM https://univienna.zoom.us/j/93427906843?pwd=YjhSejdUVW16QjVQYUh5TVNSNFNhQT09 Meeting ID: 934 2790 6843 Passcode: 073703
Contact:A. Hoang, M. Procura