Events calendar

Giovanni Stagnitto

The Large Hadron Collider (LHC) at CERN, along with its upcoming high-luminosity upgrade (HL-LHC), will provide a vast amount of high-energy data of outstanding quality. To fully leverage this experimental precision, theoretical predictions must reach a comparable level of accuracy. This is essential not only to impose stringent constraints on the Standard Model (SM), but also to explore uncharted domains, such as the Higgs potential, and to search for signs of new physics. Future colliders will likewise require highly-accurate theoretical inputs to achieve their ambitious physics goals. The Electron-Ion Collider at Brookhaven National Laboratory will serve as a cutting-edge facility for studies in quantum chromodynamics (QCD) and for probing the internal structure of hadrons. Furthermore, the proposed Future Circular Collider (FCC) at CERN is envisioned as the next-generation facility for exploring physics beyond the Standard Model, through both direct and indirect searches. In this talk, I will highlight a selection of my contributions to the precision challenge at the LHC and future colliders. These include QCD predictions for processes involving identified light and heavy hadrons (from the fragmentation of charm and bottom quarks), as well as fixed-order calculations at next-to-next-to-leading order (NNLO) and beyond, and their matching to Monte Carlo parton showers. I will also outline possible future research directions within the community’s ongoing effort to achieve percent-level precision.

Federico Buccioni

The Large Hadron Collider (LHC) generates vast amounts of high-quality data that probe elementary particle interactions at unprecedented energies, enabling the scrutiny of forces governing Nature at the smallest scales. The 2012 landmark discovery of the Higgs boson completed the particle content  of the Standard Model (SM), but there is still much to explore regarding the interactions among these particles. With exquisite theoretical control, great opportunities lie before us. The LHC’s broad energy range, exceptional precision, and rich experimental program allow for investigations of the underlying Physics through various lenses. Indeed, first-principle yet highly complex calculations performed within the SM are key to our quantitative understanding of collider reactions. In this talk, I will discuss how recent advances in precision calculations can inform us about the strong and electroweak forces in disparate regimes, offering a rich laboratory to study them at the deepest level.

Aleksas Mazeliauskas

Complex many-body systems often display emergent phenomena that cannot be understood solely from the properties of their individual constituents. Key insights into such behavior come from experiments with maximally interacting quantum systems. For example, high-energy collisions at the Large Hadron Collider create dense matter composed of strongly interacting quarks and gluons. Surprisingly, hydrodynamics applies even to the tiny droplets of this quark-gluon plasma—structures thousands of times smaller than a water molecule. Another illustrative example involves ultracold atomic gases confined in optical traps, which also exhibit collective dynamics governed by strong correlations. Out-of-equilibrium quantum systems can display universal features that transcend the details of their microscopic makeup. This universality is often tied to attractor behavior, wherein the system’s evolution becomes largely independent of its initial state. Understanding such attractors is crucial for describing how quantum chromodynamic (QCD) matter thermalizes following high-energy nuclear collisions. In this talk, I will review our current theoretical understanding of QCD thermalization, the emergence of non-thermal and hydrodynamic attractors, and the universal behaviors shared across strongly correlated quantum systems.

Jacopo Fumagali

Cosmic inflation represents the leading paradigm for understanding the physics of the very early Universe. Its success stems from the ability to coherently connect the primordial epoch with a variety of observations, offering a unique window into physical processes at otherwise inaccessible energy scales. At short scales (below 1 Mpc), the inflationary dynamics remain largely unconstrained. This explicitly allows for scenarios where scalar fluctuations are significantly amplified compared to the scales probed by the Cosmic Microwave Background, potentially leading to the formation of primordial black holes and a detectable stochastic gravitational-wave background. This latter constitutes a leading target for future gravitational wave observatories such as the recently adopted LISA (Laser Interferometer Space Antenna) mission. Consequently, non-standard dynamics at small scales have become a primary focus of the community, pushing us into uncharted territory in both theory and data analysis, where traditional techniques and results cannot be easily extended. I will outline how my studies on small-scale features in the gravitational-wave background, reconstruction pipelines for primordial signals, and loop corrections in inflation puts me in a privileged position to take on these challenges, which lie at the core of my future research quest.

Joseph Davighi

Intervenant: Antoine Bourget

In the last decade, the concept of symmetry in quantum field theory has been vastly generalized, to so-called higher-form symmetries, and, more broadly, categorical symmetries, which can sometimes be non-invertible. If these statements sound weird to you, this lecture series is aimed at you.

I will introduce these generalized symmetries using the viewpoint of gauge (Maxwell and Yang-Mills) theories and anomalies, which both motivate the introduction of the new concepts and illustrate them.

Topics covered:

• Charge conservation and global symmetries in Maxwell theory
• Anomalies and higher-group symmetries
• Self-dual Yang-Mills theories and non-invertible symmetries
• Higher categories as the framework for describing symmetries

Livestream on youtube.com/IPhT-TV: no subscription required

Videoconference: subscribe to the course newsletter to receive links

I will discuss ultralight new physics as a possible way to explain some of the puzzles in modern particle physics and cosmology. After a brief introduction on ultralight new physics and their theoretical motivations, I will discuss several ways to experimentally and observationally confirm or falsify ultralight new physics. Using recent advancements on precision astrophysics (pulsar timing array, astrometry, etc) and quantum sensors (atomic clock, gravity wave detectors), I will show that a wide variety of ultralight new physics can be tested in near future. I will conclude with several potential future directions and challenges for ultralight new physics searches. 

Mariana Carillo-Gonzalez

Intervenant: Antoine Bourget

In the last decade, the concept of symmetry in quantum field theory has been vastly generalized, to so-called higher-form symmetries, and, more broadly, categorical symmetries, which can sometimes be non-invertible. If these statements sound weird to you, this lecture series is aimed at you.

I will introduce these generalized symmetries using the viewpoint of gauge (Maxwell and Yang-Mills) theories and anomalies, which both motivate the introduction of the new concepts and illustrate them.

Topics covered:

• Charge conservation and global symmetries in Maxwell theory
• Anomalies and higher-group symmetries
• Self-dual Yang-Mills theories and non-invertible symmetries
• Higher categories as the framework for describing symmetries

Livestream on youtube.com/IPhT-TV: no subscription required

Videoconference: subscribe to the course newsletter to receive links

TBA.

TBA.

TBA.

Bérengère Dubrulle (IRAMIS/SPEC)

Abstract: 

Turbulence, a phenomenon observed by physicists in natural and laboratory flows, is thought to be described by Navier-Stokes equations (NSE). Yet, it is not yet known whether the Cauchy problem is well posed for these equations, and whether solutions of finite energy are regular or unique. In the physics community, the “singularity hypothesis” is generally discarded, following the reasonable principle that “singularities are a mathematical curiosity, in nature they do not exist”.

In these lectures, I will discuss how recent progresses in mathematics, numerical simulations and laboratory experiments changed such simple vision leading to a new picture where quasi-singularities living beyond Kolmogorov scale play a central role.

Topics covered:

• The basic empirical laws of turbulence
• Some mathematical aspects of Navier-Stokes equations
• Symmetries and their consequences
• Singularities and anomalous laws
• Predictability of turbulence

Conférence-visite de l’IPhT le 17 juin (de 9hà 11h dans l’amphi Bloch, bât 773 Orme des Merisiers, centre CEA de Saclay (144 places)

• 1. La physique quantique par le prisme des symétries

Intervenant: Thibaud Raymond

La physique quantique est notre meilleure description actuelle des phénomènes se produisant aux plus petites échelles de la matière. Elle semble parfois étrange — presque paradoxale — lorsque confrontée à nos intuitions du quotidien. Pourtant, elle est la source des prédictions expérimentales les plus précises et mieux vérifiées parmi toutes les sciences. Comment peuvent bien faire les physiciens pour la manipuler avec autant de succès ? On verra que la notion de symétrie joue un rôle central dans une histoire qui nous emmènera des spectres d’absorption des atomes à la description des interactions fondamentales en passant par le tableau périodique des éléments, et qui continue activement de nos jours.

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• 2. film IPhT, une expérience théorique

•  3. Les trous noirs et le paradoxe de l’information

Intervenant: Raphaël Dulac

Un trou noir est une région de l’espace où la gravité est tellement intense que rien ne peut en sortir, pas même la lumière. D’après la relativité générale, toute information sur ce qui tombe dedans semble perdue à jamais. Mais la mécanique quantique prédit que l’information ne peut jamais disparaître. Cette tension est communément appelée le paradoxe de l’information dans les trous noirs. Nous expliquerons ce qu’est un trou noir ainsi que ce paradoxe, rendu célèbre par Stephen Hawking. Nous présenterons une possibilité de résolution moderne à l’aide d’une théorie de gravité quantique

-questions

TBA.

Bérengère Dubrulle (IRAMIS/SPEC)

Abstract: 

Turbulence, a phenomenon observed by physicists in natural and laboratory flows, is thought to be described by Navier-Stokes equations (NSE). Yet, it is not yet known whether the Cauchy problem is well posed for these equations, and whether solutions of finite energy are regular or unique. In the physics community, the “singularity hypothesis” is generally discarded, following the reasonable principle that “singularities are a mathematical curiosity, in nature they do not exist”.

In these lectures, I will discuss how recent progresses in mathematics, numerical simulations and laboratory experiments changed such simple vision leading to a new picture where quasi-singularities living beyond Kolmogorov scale play a central role.

Topics covered:

• The basic empirical laws of turbulence
• Some mathematical aspects of Navier-Stokes equations
• Symmetries and their consequences
• Singularities and anomalous laws
• Predictability of turbulence

Intervenante: Laura Foini

Résumé disponible ultérieurement.

Bérengère Dubrulle (IRAMIS/SPEC)

Abstract: 

Turbulence, a phenomenon observed by physicists in natural and laboratory flows, is thought to be described by Navier-Stokes equations (NSE). Yet, it is not yet known whether the Cauchy problem is well posed for these equations, and whether solutions of finite energy are regular or unique. In the physics community, the “singularity hypothesis” is generally discarded, following the reasonable principle that “singularities are a mathematical curiosity, in nature they do not exist”.

In these lectures, I will discuss how recent progresses in mathematics, numerical simulations and laboratory experiments changed such simple vision leading to a new picture where quasi-singularities living beyond Kolmogorov scale play a central role.

Topics covered:

• The basic empirical laws of turbulence
• Some mathematical aspects of Navier-Stokes equations
• Symmetries and their consequences
• Singularities and anomalous laws
• Predictability of turbulence