CPT

Calendar of Physics Talks Vienna

Canonical Quantization of Singular Spaces: Symmetry Reduction, Mass Gap Bounds, and Non-smooth Calculus (Vienna Theory Lunch Seminar)
Speaker:Luca Mrini (University of Vienna)
Abstract:We study the canonical quantization of singular configuration spaces and identify natural generalizations of the core structures of quantum mechanics. In this way, we propose new tools to probe non-perturbative quantum properties of singular systems, including those arising from symmetry constraints and gauge theories. Under minimal assumptions, we construct a Hilbert space of quantum states, generalized position and momentum operators, a kinetic-plus-potential Hamiltonian, and unitary quantum dynamics for such systems. Our main result is a new technique to bound the mass gap of certain singular systems obtained via symplectic reduction by analyzing the curvature of the non-reduced configuration space. [[part of the "Vienna Theory Lunch Seminar, see https://lunch-seminar.univie.ac.at ]]
Date: Tue, 04.11.2025
Time: 12:15
Duration: 75 min
Location:TU Wien: Wiedner Hauptstr. 8-10, green area, 5th floor, seminar room DA05E10
Contact:Luciano Montecchio

What if phi^4 theory in 4 dimensions is non-trivial in the continuum?
Speaker:Paul ROMATSCHKE (TU Vienna)
Abstract:Traditionally, scalar phi^4 theory in four dimensions is thought to be quantum trivial in the continuum. In this talk, I critically review what quantum triviality is, and in particular which parts of the idea have actually been mathematically proved as opposed to just assumed to be true. I go on to exploit loopholes in the mathematical proofs, notably multi-component fields, to present a concrete calculation that avoids quantum triviality in scalar phi4 theory in the continuum. There is a price to pay to avoid triviality, but there are also potentially rich rewards. Your mileage will vary. Whatever the outcome, it is great fun to work on this subject!
Date: Tue, 04.11.2025
Time: 14:00
Duration: 60 min
Location:Erwin-Schroedinger-Lecture Hall, 1090 Vienna, Boltzmanngasse 5, 5th floor
Contact:S. Fredenhagen, M. Sperling

q-Desics - Particle motion in quantum gravity
Speaker:Benjamin Koch (TU Wien)
Abstract: We revisit the motion of test particles in quantum-gravitational backgrounds by introducing the concept of q–desics, quantum-corrected analogs of classical geodesics. Unlike standard approaches that rely solely on the expectation value of the spacetime metric, this formulation is based on the expectation value of quantum operators, such as the affine connection operator. This allows to capture richer (quantum)-geometric information. Exemplary results include lightlike radial motion and circular motion with quantum gravitational corrections far above the Planck scale. This framework provides a refined description of motion in quantum spacetimes and opens new directions for probing the interface between quantum gravity and classical general relativity. Note: ArXiv paperpitch: https://youtu.be/sf3A2qnE3F4, Live on YouTube: https://www.youtube.com/c/IQOQIVienna
Date: Tue, 04.11.2025
Time: 15:30
Duration: 45 min
Location:Boltzmanngasse 3, 2nd floor, 1090 Vienna
Contact:Hosted by: Caslav Brukner

ESI Medal 2025 Award Ceremony
Speaker:Georg Kresse, Mariana Rossi, Giuseppe Foffi, Michele Parrinello (U of Vienna, MPI Hamburg, U of Paris-Saclay, ETH Zurich and Istituto Italiano di Tecnologia in Genova)
Abstract:Prof. Michele Parrinello (ETH Zurich and Istituto Italiano di Tecnologia in Genova) is honored for his seminal contributions to computational science, particularly through the development of groundbreaking algorithms that have opened new frontiers in soft matter, biological, and condensed matter physics, as well as for applying these methods to solve important open problems. Among his most recent achievements are the advancement of metadynamics sampling techniques, which have revolutionized the study of complex free-energy landscapes — including those associated with protein conformational changes — and the pioneering integration of machine learning with molecular dynamics, a transformative leap that is redefining the frontiers of numerical simulations. He is also recognized for his efforts in promoting promoting transparency and reproducibility in computational science.
Date: Fri, 07.11.2025
Time: 14:00
Duration: 240 min
Location:Erwin Schrödinger Institute, Boltzmann Lecture Hall, Boltzmanngasse 9, 1090 Wien
Contact:secr@esi.ac.at, https://www.esi.ac.at/events/e593/