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The SEMPARIS seminar webserver hosts annoucements of all seminars taking place in Paris area, in all topics of physics, mathematics and computer science. It allows registered users to receive a selection of announcements by email on a daily or weekly basis, and offers the possibility to archive PDF or Powerpoint files, making it available to the scientific community. [ More information ]
| Upcoming Seminars | ||
| [ scheduler view ] | ||
| Tuesday 7 May 2024, 10:30 at IHES, Amphithéâtre Léon Motchane | MATH-IHES (TBA) | math |
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| Abstract: | The course is based on a minibook that will be published by Springer. The text below is a shortened preface to this book. In the conventional exposition of quantum mechanics, we work in Hilbert space and examine operators within this space. Self-adjoint operators are associated with physical quantities. Physicists predominantly use this methodology, however, it has its limitations. In this course we explore alternative viewpoints; our exposition does not depend on standard textbooks. We consider the algebraic approach, where the initial point is an algebra of observables, an associative algebra with involution, in which the self-adjoint elements are observables. This approach is nearly as old as quantum mechanics itself. In addition, we discuss the geometric approach, where the initial point is a set of states. This viewpoint was advocated in my recent papers; it is much more general. We demonstrate within the framework of this approach that quantum mechanics can be viewed as classical mechanics where our devices permit us to observe only a subset of physical quantities. Furthermore, we show that using this approach we can construct a wide class of physical theories that generalize quantum mechanics. We highlight that the emergence of probabilities in quantum theory can be derived from decoherence caused by adiabatic interaction with a random environment. We underscore that the concept of a particle is not primary in quantum theory. If the theory is translation-invariant we define particles as elementary excitations of the ground state. Quasiparticles are elementary excitations of any translation-invariant state. We analyze the concept of scattering but we do not utilize the concept of a field and do not assume locality and Poincare invariance. We discuss not only the conventional scattering matrix (related to scattering cross-sections) but also the concept of an inclusive scattering matrix, which is closely related to the concept of inclusive scattering cross-sections. Scattering matrix can be expressed in terms of Green's functions by the well-known formula belonging to Lehmann, Symanczyk, and Zimmermann, and the inclusive scattering matrix can be expressed in terms of generalized Green's functions, which first appeared in nonequilibrium statistical physics in Keldysh formalism. As a concrete realization of the geometric approach, we describe the formalism of L-functionals where states are represented by non-linear functionals corresponding to positive functionals on Weyl and Clifford algebras (to states in the algebraic approach). L-functionals can be applied to solve the infrared problem in quantum electrodynamics. | |
| Thursday 9 May 2024, 10:00 at IMO, Online-only. Zoom link by subscribing at https://seedseminar.apps.math.cnrs.fr/ | SEED (Seed Seminar of Mathematics and Physics) | math-ph |
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| Thursday 9 May 2024, 11:00 at IMO, Online-only. Zoom link by subscribing at https://seedseminar.apps.math.cnrs.fr/ | SEED (Seed Seminar of Mathematics and Physics) | math-ph |
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| Friday 10 May 2024, 10:30 at IHES, Amphithéâtre Léon Motchane | MATH-IHES (TBA) | math |
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| Abstract: | The course is based on a minibook that will be published by Springer. The text below is a shortened preface to this book. In the conventional exposition of quantum mechanics, we work in Hilbert space and examine operators within this space. Self-adjoint operators are associated with physical quantities. Physicists predominantly use this methodology, however, it has its limitations. In this course we explore alternative viewpoints; our exposition does not depend on standard textbooks. We consider the algebraic approach, where the initial point is an algebra of observables, an associative algebra with involution, in which the self-adjoint elements are observables. This approach is nearly as old as quantum mechanics itself. In addition, we discuss the geometric approach, where the initial point is a set of states. This viewpoint was advocated in my recent papers; it is much more general. We demonstrate within the framework of this approach that quantum mechanics can be viewed as classical mechanics where our devices permit us to observe only a subset of physical quantities. Furthermore, we show that using this approach we can construct a wide class of physical theories that generalize quantum mechanics. We highlight that the emergence of probabilities in quantum theory can be derived from decoherence caused by adiabatic interaction with a random environment. We underscore that the concept of a particle is not primary in quantum theory. If the theory is translation-invariant we define particles as elementary excitations of the ground state. Quasiparticles are elementary excitations of any translation-invariant state. We analyze the concept of scattering but we do not utilize the concept of a field and do not assume locality and Poincare invariance. We discuss not only the conventional scattering matrix (related to scattering cross-sections) but also the concept of an inclusive scattering matrix, which is closely related to the concept of inclusive scattering cross-sections. Scattering matrix can be expressed in terms of Green's functions by the well-known formula belonging to Lehmann, Symanczyk, and Zimmermann, and the inclusive scattering matrix can be expressed in terms of generalized Green's functions, which first appeared in nonequilibrium statistical physics in Keldysh formalism. As a concrete realization of the geometric approach, we describe the formalism of L-functionals where states are represented by non-linear functionals corresponding to positive functionals on Weyl and Clifford algebras (to states in the algebraic approach). L-functionals can be applied to solve the infrared problem in quantum electrodynamics. | |
| Friday 10 May 2024, 14:00 at IHES, Amphithéâtre Léon Motchane | PT-IHES (Séminaire de physique théorique de l'IHES) | hep-th |
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| Abstract: | The simplest topologically ordered phase in 2+1D is the deconfined phase of Z2 lattice gauge theory. There are two reasonably well-understood ways to exit the deconfined phase: the Higgs transition, where electric charge (the "e" anyon) condenses, and the confinement transition, where magnetic charge (the "m" anyon) condenses. However, we can also exit the deconfined phase via the self-dual line in the phase diagram, where there is a symmetry between "e" and "m". What happens here is more mysterious. If this transition is continuous, it may be the simplest critical point with no useful continuum Lagrangian (as yet). After reviewing the formulation of the model as the statistical mechanics of membranes, I will describe clear Monte Carlo evidence for the continuity of the self-dual transition. I will sketch why it is not a conventional "Landau" critical point. Separately, I will use the membrane formulation to describe a very concrete and intuitive way of understanding the emergent higher-form symmetries which appear in part of the phase diagram (and which are the reason that the Higgs and confinement transitions can be understood using Landau theory, despite lacking local order parameters). Work with Andres Somoza and Pablo Serna (https://arxiv.org/abs/2012.15845 and https://arxiv.org/abs/2403.04025). | |
| Monday 13 May 2024, 10:45 at LPTMC, campus Jussieu, couloir 12-13, 5ème étage, salle 5-23 | SEM-LPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée) | cond-mat |
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| Tuesday 14 May 2024, 10:30 at IHES, Amphithéâtre Léon Motchane | MATH-IHES (TBA) | math |
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| Abstract: | The course is based on a minibook that will be published by Springer. The text below is a shortened preface to this book. In the conventional exposition of quantum mechanics, we work in Hilbert space and examine operators within this space. Self-adjoint operators are associated with physical quantities. Physicists predominantly use this methodology, however, it has its limitations. In this course we explore alternative viewpoints; our exposition does not depend on standard textbooks. We consider the algebraic approach, where the initial point is an algebra of observables, an associative algebra with involution, in which the self-adjoint elements are observables. This approach is nearly as old as quantum mechanics itself. In addition, we discuss the geometric approach, where the initial point is a set of states. This viewpoint was advocated in my recent papers; it is much more general. We demonstrate within the framework of this approach that quantum mechanics can be viewed as classical mechanics where our devices permit us to observe only a subset of physical quantities. Furthermore, we show that using this approach we can construct a wide class of physical theories that generalize quantum mechanics. We highlight that the emergence of probabilities in quantum theory can be derived from decoherence caused by adiabatic interaction with a random environment. We underscore that the concept of a particle is not primary in quantum theory. If the theory is translation-invariant we define particles as elementary excitations of the ground state. Quasiparticles are elementary excitations of any translation-invariant state. We analyze the concept of scattering but we do not utilize the concept of a field and do not assume locality and Poincare invariance. We discuss not only the conventional scattering matrix (related to scattering cross-sections) but also the concept of an inclusive scattering matrix, which is closely related to the concept of inclusive scattering cross-sections. Scattering matrix can be expressed in terms of Green's functions by the well-known formula belonging to Lehmann, Symanczyk, and Zimmermann, and the inclusive scattering matrix can be expressed in terms of generalized Green's functions, which first appeared in nonequilibrium statistical physics in Keldysh formalism. As a concrete realization of the geometric approach, we describe the formalism of L-functionals where states are represented by non-linear functionals corresponding to positive functionals on Weyl and Clifford algebras (to states in the algebraic approach). L-functionals can be applied to solve the infrared problem in quantum electrodynamics. | |
| Tuesday 14 May 2024, 11:00 at LPTMS, Salle des séminaires du FAST et du LPTMS, bâtiment Pascal n°530 | LPTMS (Séminaire du Laboratoire de Physique Théorique et Modèles Statistiques (Orsay)) | cond-mat.stat-mech |
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| Abstract: | After introducing the collective behaviors observed in fish schools, I will outline a methodology for quantitatively measuring social interactions (attraction/repulsion; alignment) within animal groups. The reconstructed interactions can then be directly implemented in analytical models which quantitatively reproduce the collective motion of fish. I will also briefly address an alternative machine learning approach designed to produce realistic fish trajectories. In the latter part of the presentation, I will explore various applications of such analytical or machine learning behavioral models in the context of robotic and drone platforms, and a virtual reality setup… for fish! In particular, our robot-fish and VR setups constitute original and powerful tools to study the social dynamics of fish and their response to controlled perturbations. | |
| Tuesday 14 May 2024, 14:30 at IHES, Amphithéâtre Léon Motchane | MATH-IHES (TBA) | math |
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| Abstract: | The partition function of topological string theory is an asymptotic series in the topological string coupling and provides in a certain limit a generating function of Gromov-Witten (GW) invariants of a Calabi-Yau threefold. I will discuss how the resurgence analysis of the partition function allows one to extract BPS invariants of the same underlying geometry. I will further discuss how the analytic functions in the topological string coupling obtained by Borel summation admit a dual expansion in the inverse of the topological string coupling leading to another asymptotic series at strong coupling and to the notion of topological string S-duality. This S-duality leads to a new modular structure in the topological string coupling. I will also discuss relations to difference equations and the exact WKB analysis of the mirror geometry. This is based on various joint works with Lotte Hollands, Arpan Saha, Iván Tulli and Jörg Teschner as well as on work in progress. | |
| Wednesday 15 May 2024, 13:30 at DPT-PHYS-ENS, ConfIV (E244) - Dépt de Physique de l'ENS - 24 rue Lhomond 75005 PARIS | COLLOQUIUM-ENS (Colloquium of the Physics Department of ENS) | physics |
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| Abstract: | TBA | |
| Thursday 16 May 2024, 14:00 at LPTMC, campus Jussieu, couloir 12-13, 5ème étage, salle 5-23 | SEM-LPTMC (Séminaire du Laboratoire de Physique Théorique de la Matière Condensée) | cond-mat |
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| Tuesday 21 May 2024, 11:00 at LPTMS, Salle des séminaires du FAST et du LPTMS | LPTMS (Séminaire du Laboratoire de Physique Théorique et Modèles Statistiques (Orsay)) | cond-mat.stat-mech |
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| Wednesday 22 May 2024, 12:45 at LPENS, 3 rue d'Ulm | FORUM-ENS (Forum de Physique Statistique @ ENS) | cond-mat.stat-mech |
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| Abstract: | TBA | |
| Thursday 23 May 2024, 11:00 at LPTHE, bibliothèque du LPTHE, tour 13-14, 4eme étage | SEM-DARBOUX (Séminaire Darboux - physique théorique et mathématiques) | hep-th|math.DG |
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| Abstract: | In the last 50 years the study of the Monge-Ampère operator has played a central role in order to solve geometric problems, such as the existence of special metrics (e.g. Kähler-Einstein, cscK) on a compact Kähler manifold. In this talk I am going to present some recent developments in “singular” settings: we will work with a singular variety and we look for singular metrics. The talk is based on a series of joint papers with Támas Darvas and Chinh Lu. | |
| Thursday 23 May 2024, 14:00 at
LPTMC,
LPTMC seminar room, Jussieu, towers 12-13, 5th floor, room 523 ( [11] A.Jouan et al. Nature Elec. 3, 201–206 (2020). ) | SEM-EXCEP (Seminaire exceptionnel) | cond-mat |
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| Abstract: | [For the full abstract see the attached pdf]. A key feature of these electronic systems lies in the possibility to control their carrier density by electric field effect, which results in gate-tunability of both superconductivity and Rashba spin-orbit coupling. In this talk, I will review complementary dc and microwave transport measurements conducted on SrTiO3 and KTaO3-based interfaces employing both back-gate and top-gate configurations. I will discuss, in particular, gate-induced multigap superconductivity [8,9] and the role of phase fluctuations within the Berezinskii-Kosterlitz-Thouless model [10]. I will also present the realization of field effect devices whose physical properties, including superconductivity and Rashba spin-orbit coupling, can be tuned over a wide range of electrostatic doping, and discuss the potential of oxides interfaces for the realization of mesoscopic devices [11]. | |
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| Monday 27 May 2024, 13:30 at LPENS, U209 (29 rue d'Ulm) | LPENS-MDQ (Séminaire Matériaux et Dispositifs Quantiques du LPENS) | cond-mat |
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| Wednesday 29 May 2024, 12:45 at LPENS, 3 rue dUlm, College de France | FORUM-ENS (Forum de Physique Statistique @ ENS) | cond-mat.stat-mech |
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| Wednesday 29 May 2024, 15:00 at IMO, Online-only. Zoom link by subscribing at https://seedseminar.apps.math.cnrs.fr/ | SEED (Seed Seminar of Mathematics and Physics) | math-ph |
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| Monday 3 June 2024, 11:00 at IPHT, Salle Claude Itzykson, Bât. 774 | IPHT-STA (Séminaire de Physique Statistique, CEA/Saclay) | cond-mat |
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| Abstract: | TBA | |
| Tuesday 4 June 2024, 11:00 at LPTMS, Salle des séminaires du FAST et du LPTMS, bâtiment Pascal n°530 | LPTMS (Séminaire du Laboratoire de Physique Théorique et Modèles Statistiques (Orsay)) | cond-mat.stat-mech |
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| Wednesday 5 June 2024, 13:30 at DPT-PHYS-ENS, ConfIV (E244) - Dépt de Physique de l'ENS - 24 rue Lhomond 75005 PARIS | COLLOQUIUM-ENS (Colloquium of the Physics Department of ENS) | physics |
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| Wednesday 5 June 2024, 13:45 at LPENS, 3 rue d'Ulm | FORUM-ENS (Forum de Physique Statistique @ ENS) | cond-mat.stat-mech |
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| Abstract: | TBA | |
| Tuesday 11 June 2024, 11:00 at LPTMS, Salle des séminaires du FAST et du LPTMS, bâtiment Pascal n°530 | LPTMS (Séminaire du Laboratoire de Physique Théorique et Modèles Statistiques (Orsay)) | cond-mat.stat-mech |
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| Wednesday 12 June 2024, 14:15 at IPHT, Salle Claude Itzykson, Bât. 774 | IPHT-MAT (Séminaire de matrices, cordes et géométries aléatoires) | hep-th |
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| Abstract: | TBD | |
| Wednesday 19 June 2024, 12:45 at LPENS, 3 rue dUlm | FORUM-ENS (Forum de Physique Statistique @ ENS) | cond-mat.stat-mech |
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| Abstract: | TBA | |
| Wednesday 19 June 2024, 14:15 at IPHT, Salle Claude Itzykson, Bât. 774 | IPHT-MAT (Séminaire de matrices, cordes et géométries aléatoires) | hep-th |
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| Abstract: | TBD | |
| Tuesday 25 June 2024, 11:00 at LPTMS, Salle des séminaires du FAST et du LPTMS | LPTMS (Séminaire du Laboratoire de Physique Théorique et Modèles Statistiques (Orsay)) | cond-mat.stat-mech |
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| Tuesday 29 April 2025, 14:00 at IMO, Online-only. Zoom link by subscribing at https://seedseminar.apps.math.cnrs.fr/ | SEED (Seed Seminar of Mathematics and Physics) | math-ph |
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