Event report · 26 September 2026 · Shibuya Hikarie, Tokyo
The last session on day two of Newton Fes, a large event built around the Japanese science magazine Newton, brought together Yobinori Takumi, who runs the popular YouTube channel teaching university maths and physics, and Yasunori Nomura, a theoretical physicist and professor at UC Berkeley. They went from how physics learned to live with infinities to black holes, the shape of the universe and Nomura's research this year. This report is based on notes taken in the hall.
In short
TalkThe conversation began with the infinities that show up in physics calculations, and with the names Sin-Itiro Tomonaga and Kenneth Wilson.
ContextCalculate naively in the theory of electrons and light (quantum electrodynamics) and some terms come out infinite. Tomonaga found a way to absorb those infinities into quantities we actually measure, such as the electron's mass and charge — renormalisation — and shared the 1965 Nobel Prize in Physics with Feynman and Schwinger. Kenneth Wilson recast theories as things that change with the scale at which you look — the renormalisation group — and received the 1982 Nobel Prize. Infinities stopped being a sign that a theory is wrong and became a sign that something is hidden at the scale you are looking at.
TalkNext came the black hole information problem raised by Stephen Hawking.
ContextHawking showed that black holes give off a faint heat (Hawking radiation) and can eventually evaporate. Then where does the information about what fell in end up? Quantum mechanics assumes information is never destroyed, so the two clash. In July this year Nomura co-authored a paper on the “complexity” of an evaporating black hole (source 3).
TalkThe notes record a discussion of what an observer who stays outside the horizon — who never falls in — sees, and the point that changing viewpoint shifts the description of space.
ContextAn observer who stays outside a black hole and one who falls through the horizon seem to give conflicting descriptions of the same events. One response is to pick an observer's standpoint and build a consistent description within it (black hole complementarity). Nomura has worked in this area for years, including a 2024 co-authored paper.
TalkWith gravity, a cube 100 units on a side can hold not “100 cubed” worth of information but only “100 squared”. The contents of a space can be described by information written on its boundary — that is holography. From there the talk moved to anti-de Sitter space (AdS) and the AdS/CFT correspondence.
ContextThe idea grew from the fact that a black hole's entropy — how much information it can hide — scales with its surface area, not its volume. 't Hooft and Susskind framed it as the holographic principle in the 1990s. In 1997 Maldacena showed, in string theory, that gravity inside anti-de Sitter space (a negatively curved spacetime) and a theory without gravity on its boundary describe the same physics in different languages.
TalkBut our universe is not anti-de Sitter space. Taking what string theory achieves in AdS and extending it to more general spacetimes is what many researchers — Nomura among them — are working on.
ContextIn February this year Nomura also co-authored a paper with Tomonori Ugajin on quantum gravity in a closed universe (source 4).
TalkSteven Weinberg's name came up too.
ContextWeinberg won the Nobel Prize for electroweak unification, and is also known for a 1987 paper estimating why the cosmological constant — the energy driving the universe's accelerating expansion — is small, using anthropic reasoning: otherwise neither galaxies nor people would exist. He connects directly to Nomura's work on the multiverse.
TalkNomura mentioned writing two papers this year and posting an explanation of dark matter on arXiv, where physics papers first appear.
ContextOn arXiv, his two dark matter papers from 2026 are:
Both are papers for specialists. What dark matter is made of is still unsettled; proposals like these are what observations will test next.
TalkThe biggest laugh came from a green-room story Yobinori Takumi told. Before the start, there was the urge to peek at the hall from backstage. But even a quick look — a “weak measurement” — might spoil things; if the audience noticed and thought “wait, is that Professor Nomura looking?”, that would be bad. Still, wanting to see how many people had come, it was impossible to resist.
ContextIn quantum mechanics, measuring a system changes its state. A weak measurement gets less information in exchange for barely disturbing the state; Aharonov and colleagues proposed it in 1988.
TalkFinally, from Nomura, who does his research in the US: enthusiasm for science is no different in America and in Japan. And even if your English isn't great, what matters is understanding the physics. A clear message for the high school and university students in the hall.