Colloquia

The funding document of CERN states that its two main missions are: "The construction of one or more labs for research in High Energy Physics… including work in the field of cosmic rays".  The second mission has been accomplished: AMS and ALICE have made decisive observations, and we now have a successful theory of Cosmic Rays and Gamma-Ray Bursts. The evidence presented in the talk has not been accepted by the community, for reasons and in ways that I shall outline.

Organised by: Alexander Zhiboedov

Coffee and tea served at 16:00

The Hubble tension—the persistent discrepancy between local and early-Universe measurements of the Hubble constant—remains one of the most intriguing puzzles in cosmology. The James Webb Space Telescope (JWST) now offers a fresh perspective on this issue by allowing an independent look at the same type of stars, Cepheids, used in the Hubble Space Telescope (HST) measurements that help define our best local estimate of cosmic expansion.  I'll show how early JWST data, although still limited in size, serves as a powerful crosscheck of the HST-based distance ladder. When comparing results across multiple techniques and research groups, we find strong consistency with the HST measurements, lending confidence to their accuracy. These comparisons suggest that the observed tension is unlikely to stem from systematic errors in HST's Cepheid distances. Though JWST's smaller sample size limits its precision for now, it already provides valuable validation of the HST approach. As more data accumulates, JWST will play an increasingly important role in testing and refining our understanding of the expanding Universe—and perhaps help us get to the bottom of the Hubble tension.

Bio: Adam Riess is a Bloomberg Distinguished Professor at Johns Hopkins University, a distinguished astronomer at the Space Telescope Science Institute and a member of the National Academy of Sciences.
He was awarded the 2011 Nobel Prize in Physics for his leadership in the High-z Supernova Search Team's discovery that the expansion rate of the universe is accelerating. Currently, he leads the SH0ES Team in efforts to improve the measurement of the Hubble Constant and the HIgher-z Team to find and measure the most distant type Ia supernovae known to probe the origin of cosmic acceleration.

This Colloquium is part of the Invisibles25 Workshop (webpage)

Coffee and tea will be served at 16h

Organised by : Valerie Domcke, Miguel Escudero and Alexander Zhiboedov

Across the North Pole in Arctic Darkness follows legendary explorers Børge Ousland and Mike Horn as they attempt the first-ever crossing of the Arctic Ocean from Alaska to Norway in the depths of polar winter. Departing from Nome in August 2019, they sail, ski, and packraft across shifting ice and open water—crossing the North Pole in total darkness, with temperatures dropping below –40 degrees. Illuminated only by headlamps, they endure injury, equipment failure, and near-death moments in what National Geographic called "the boldest polar expedition of modern times."

More information:
In August 2019, legendary polar explorers Børge Ousland and Mike Horn departed from Nome, Alaska, sailing into the Arctic Ocean before continuing their journey on skis and packrafts. Their objective was audacious: to traverse the Arctic Ocean from Alaska to Norway, crossing the North Pole during the depths of Arctic winter. National Geographic would later call it "the boldest polar expedition of modern times."

As summer light faded in mid-September, they reached the ice edge and stepped onto the frozen ocean, skiing north into total darkness. For nearly three months, with only headlamps to light their way, they endured relentless cold, shifting ice, open leads of freezing water, injuries, equipment failures, and moments that pushed them to the brink. Temperatures plunged below –40 degrees, and the sun never rose.

On December 8, after finishing their final rationed meal, Ousland and Horn reached the ship waiting at the ice edge off the coast of Norway—having completed one of the most demanding expeditions ever undertaken.

Widely regarded as the greatest polar explorer of our time, Børge Ousland has completed solo expeditions to both the North and South Poles, as well as solo crossings of Antarctica and the Arctic from coast to coast. Through journeys to the planet's most extreme environments, he continues to redefine the limits of human endurance—one step at a time.

Coffee and tea will be served at 16h

Organised by : Nikolai Beev, Matthew Chalmers, Pippa Wells and Alexander Zhiboedov

The Deep Underground Neutrino Experiment (DUNE) is a next-generation long-baseline neutrino oscillation experiment currently under construction at the Sanford Underground Research Facility (SURF) in South Dakota, USA. DUNE will test the three-flavor neutrino paradigm in an unprecedented way, and will measure the neutrino mass ordering and the charge-parity (CP)-violating phase. Its broad physics program also includes the detection of astrophysical neutrinos and the search for signatures indicating physics beyond the Standard Model. DUNE comprises a near detector complex at Fermilab and four 17-kton Liquid Argon Time Projection Chamber (LArTPC) far detector modules located 1.5 km underground at SURF, 1,300 km away. The detectors will be exposed to a wide-band neutrino beam generated by a 1.2 MW proton beam at Fermilab, with a planned upgrade to more than 2 MW. Two 770-ton LArTPCs (ProtoDUNEs) have been operated at CERN over the last few years as testbeds for the DUNE far detectors. This talk will present the current status and recent progress of DUNE and the ProtoDUNEs, the main physics goals, and the next steps towards the full operation of the experiment.

Bio:

Inés Gil-Botella is an experimental particle physicist and research professor at CIEMAT in Madrid, specializing in neutrino physics. She was granted a CERN Summer Studentship in 1995 and earned her Ph.D. from the University of Valencia in 1999, working on the ATLAS hadronic calorimeter and supersymmetry searches with DELPHI at LEP. As a postdoctoral researcher at ETH Zurich, she led pioneering studies of supernova neutrino detection in liquid argon TPCs and contributed to the development of the ICARUS detector. Back in Spain since 2004, she founded the CIEMAT neutrino group and played a central role in the Double Chooz reactor experiment, coordinating the European analysis that achieved the first measurement of the theta13 mixing angle. Since 2013, she has focused on liquid argon detectors for the DUNE long-baseline neutrino experiment at the CERN Neutrino Platform, where she is DUNE physics co-coordinator and co-lead the DUNE photon detection system. She has participated in the Physics Preparatory Group on Detector Instrumentation for the 2026 update of the ESPP and is a member of the LHCC and DRDC committees at CERN and ECFA Detector Panel.

Coffee and tea will be served at 16h

Organised by : Augusto Ceccucci and Alexander Zhiboedov

PLEASE NOTE THE UNUSUAL DAY!

The mythical centaur (half human, half horse) has become a metaphor for human-AI collaboration.  In this talk, I explore what centaur science looks like at the intersection of artificial intelligence and fundamental physics.  I share adventures from both directions of this exchange: teaching machines to "think like a physicist" by incorporating physics principles into machine learning frameworks, and teaching physicists to "think like a machine" to maximize discovery opportunities in both experimental and theoretical physics.

Bio:
Jesse Thaler joined the MIT Physics Department in 2010, and is currently a Professor in the MIT Center for Theoretical Physics — a Leinweber Institute (CTP-LI).  From 2006 to 2009, he was a fellow at the Miller Institute for Basic Research in Science at the University of California, Berkeley.  He received his Ph.D. in Physics from Harvard University in 2006, and his Sc.B. in Math/Physics from Brown University in 2002.   In 2020, Prof. Thaler became the inaugural Director of the NSF AI Institute for Artificial Intelligence and Fundamental Interactions.

Coffee and tea will be served at 16h

Organised by : Alexander Zhiboedov

Karl Jakobs is a Professor of Physics at the University of Freiburg / Germany. His main activities of research are the study of the Higgs boson and the search for extensions of the Standard Model of particle physics at the Large Hadron Collider (LHC) at CERN. He participated in experiments at CERN (UA2, ALEPH, and ATLAS) and at the US laboratory Fermilab (DØ). From 2017 to 2021 he was Scientific Leader (Spokesperson) of the ATLAS Experiment. From 2021 to 2023 he was the Chairperson of the European Committee for Future Accelerators (ECFA), and in 2024 he was appointed as Secretary to organize the new update of the European Strategy for Particle Physics. 

Coffee and tea will be served at 16h

Organised by : Andreas Hoecker

Sławosz Uznański-Wiśniewski, ESA Project Astronaut and CERN R&D Engineer, presents a first-hand perspective on the Ignis mission and his role as a mission specialist on Axiom Mission 4 (Ax-4) to the International Space Station. The presentation offers an insider's view of how a human spaceflight mission is conducted, from launch to landing, including daily life and research activities aboard the ISS.

The talk introduces the objectives of the Ignis mission, a Polish-led scientific and technological programme carried out in collaboration with ESA, POLSA, and international partners. Particular attention is given to one of the mission's flagship investigations: a scientific experiment developed at CERN, which Sławosz personally installed and operated on the ISS. He discusses the experiment's scientific goals, technical implementation, and the advantages of conducting fundamental research in a microgravity environment.

Beyond the scientific programme, the talk will also cover education and public engagement and will provide an opportunity to ask questions about the mission, the International Space Station programme, and the future of human spaceflight.

Coffee and tea will be served at 16h

Organised by : Matthew Chalmers

Quantum computing redefines the foundations of information, moving beyond classical bits and Boolean operations (AND, OR, NOT) to a framework built on quantum states and wavelike superposition. This shift enables certain problems, considered intractable, to be solved efficiently, challenging assumptions in cryptography. I examine the state of quantum computer technology and its industrial ecosystem, and I assess opportunities, risks, and emerging geopolitics of this field.

Bio:
Barry Sanders holds two Diplomas, a PhD, and a DSc from Imperial College London and is a Fellow of the Royal Society of Canada, Optica, the American Physical Society, and the UK Institute of Physics. He is known for foundational contributions to quantum optics and quantum information science. His research focuses on quantum information and on strategy for emerging dual-use technologies. Sanders is Scientific Director of the University of Calgary's Quantum City, a Senior Fellow at the Canadian Centre for International Governance and Innovation, and a Visiting Scientist at CERN. He is an advisor for CERN's Open Quantum Institute, the Google-GESDA XPRIZE for applied quantum computing, a few quantum start-ups, and quantum investors. He co-leads the Canada–France Quantum International Research Network, serves on four editorial boards, and has trained over one hundred graduate students and postdoctoral researchers.

Coffee and tea will be served at 16h

Organised by : Alexander Zhiboedov

The hundredth anniversary of quantum mechanics in 2025-26 offers opportunities to consider the history of quantum theory and ask how some of our core ideas were introduced, debated, tested, and ultimately accepted. One of the most central conceptual ingredients of quantum theory is entanglement, nowadays so important to the burgeoning field of quantum information science and technology. Yet the history of quantum entanglement---and of physicists' efforts to understand whether entanglement is a robust feature of the world rather than merely an intriguing hypothesis---has been far from straightforward. In this talk I will describe how a colorful group of physicists during the 1970s wrestled with entanglement and with John Bell's now-famous inequality, exploring the subtle interplay between quantum nonlocality and relativity amid the California counterculture scene. More recently, retracing the history of efforts to conduct experimental tests of Bell's inequality helped to catalyze novel tests, which have aimed to close a series of loopholes, including the recent "Cosmic Bell" experiments. Together this new generation of experiments provides compelling evidence for quantum entanglement while constraining various alternative models---which exploit subtle loopholes---more thoroughly than ever before.
 

Coffee and tea will be served at 15h30

Organised by : Alexander Zhiboedov

The European nuclear physics community, under the guidance of NuPECC, has developed its vision for the coming decade and published it as the NuPECC Long Range Plan 2024. The process took slightly more than two years and involved almost 300 scientists in the steering committee and in ten thematic working groups, plus a town meeting open to the full community. The resulting document presents an outlook and recommendations for five physics topics, applications, and the necessary infrastructures (several of them located at CERN) and tools. Two chapters on open science and data as well as nuclear science – people and society were added compared to previous versions. I will present the key findings and outcome of this process which describes the European Strategy for Nuclear Physics.

Coffee and tea will be served at 16h

Organised by : Matthew Chalmers

Coffee and tea will be served at 16h

Organised by : Matthew Chalmers

Coffee and tea will be served at 16h

Organised by : Matthew Chalmers