Biggest Breakthroughs in Physics: 2024

This video surveys three cutting-edge physics breakthroughs, all revolving around the theme that the universe’s deepest mysteries are yielding tantalizing, yet incomplete, clues. It begins with dark energy, the unknown repulsive force comprising 68% of the cosmos, and highlights DESI’s 2024 finding that this force may be weakening over time—a result contradicting Einstein’s constant model but still shy of formal discovery at 3.5 sigma. It then explores supersolids, a bizarre phase of matter that is simultaneously a rigid crystal and a frictionless superfluid, which researchers at Innsbruck finally created and imaged in the lab, revealing quantum vortices and suggesting a surprising connection to neutron star “glitches.” Finally, the video introduces the amplituhedron, a geometric object that simplifies particle collisions, and describes a 2024 breakthrough by Figueiredo and Arkani-Hamed that used hidden “zeros” to link this abstract geometry to the real-world physics of pions and gluons. Together, these stories illustrate how physicists are using novel data and radical mathematical tools to push toward answers on the universe's most profound questions.

• ▶ 0:07 Dark energy is one of physics' biggest unsolved mysteries, making up 68% of the universe and driving matter apart via a repulsive force—though "we really don't know what it is."
• ▶ 0:23 Einstein's cosmological constant (lambda) was his early idea of energy infused in space itself, later supported by the 1998 Nobel-winning discovery of dark energy's accelerating expansion.
• ▶ 4:01 DESI's 2024 data delivered a startling hint: dark energy may be weakening over time, contradicting the constant Lambda-CDM model—but at 3.5 sigma, it is not yet a formal discovery, leaving confirmation to future data and a potential Nobel Prize for a successful theorist.
• ▶ 5:52 Supersolids are a phase of matter that is both solid and liquid, possessing a rigid crystal-like structure while flowing with zero viscosity as a superfluid—a possibility debated since the 1950s.
• ▶ 8:03 In 2024, University of Innsbruck researchers created and observed a supersolid in the lab by using laser-cooled dysprosium atoms and steering their magnetic field about 50 times per second, producing images of quantum vortices that confirmed the material's dual nature.
• ▶ 9:37 The experiment revealed an unexpected astrophysical link: the inner crust of neutron stars is predicted to be a supersolid, and escaping vortices in this supersolid interior may explain star "glitches," or sudden changes in rotation speed.
• ▶ 11:13 The amplituhedron is introduced as a geometric object whose hidden geometry answers what happens when particles collide, and a 2024 breakthrough by Carolina Figueiredo and Nima Arkani-Hamed linked this geometry to real-world physics.
• ▶ 11:41 Predicting collisions is hard because quantum physics forbids observing the process in between; physicists sum up all possible Feynman diagrams to get a scattering amplitude, but the number of diagrams can become computationally intractable.
• ▶ 14:19 Figueiredo’s breakthrough: by studying collisions where the numerator of scattering amplitudes becomes small, she found hidden zeros—forbidden collisions shared by associahedron theory and real-world pions/gluons—showing the same master function and marking the first geometric calculation of real-world particle amplitudes.

• ▶ 0:07 Dark Energy and the Cosmological Constant (0:07 - 5:52) - - Describes dark energy, the cosmological constant, and DESI's map challenging Lambda-CDM.
• ▶ 5:52 Supersolids: Creation and Discovery (5:52 - 11:13) - - Explains supersolids as quantum phases, their history, the Innsbruck experiment, and neutron-star implications.
• ▶ 11:13 The Amplituhedron and Particle Collisions (11:13 - 16:46) - - Introduces amplituhedron geometry as a replacement for Feynman diagrams and recent real-world calculations.