PRISMA Colloquium

More than 25 years after the discovery of the accelerated expansion of the Universe, understanding dark energy remains the biggest open problem in cosmology. The Dark Energy Spectroscopic Instrument (DESI) is the first of a new generation of “Stage-IV” cosmology survey experiments aiming to improve this understanding. By precisely mapping the positions of over 50 million galaxies and quasars, DESI is measuring the expansion history of the Universe over the last 11 billion years. I will describe the experiment and discuss the cosmological results from the first 3 years of data, from baryon acoustic oscillations (BAO) and the full shape of the clustering power spectrum. These include exciting hints of an anomaly in the cosmological constant model of dark energy, and unprecedented constraints on the neutrino mass scale. I will describe the nature of the data constraints and comment on the implications for fundamental physics models.

Understanding the confinement mechanism in gauge theories and the universality of effective string-like descriptions of gauge flux tubes remains a fundamental challenge in modern physics. We probe string modes of motion with dynamical matter in a digital quantum simulation of a (2+1) dimensional gauge theory using a superconducting quantum processor with up to 144 qubits, stretching the hardware capabilities with quantum-circuit depths comprising up to 192 two-qubit layers. We realize the Z_2-Higgs model (Z_2HM) through an optimized embedding into a heavy-hex superconducting qubit architecture, directly mapping matter and gauge fields to vertex and link superconducting qubits, respectively. Using the structure of local gauge symmetries, we implement a comprehensive suite of error suppression, mitigation, and correction strategies to enable real-time observation and manipulation of electric strings connecting dynamical charges. Our results resolve a dynamical hierarchy of longitudinal oscillations and transverse bending at the end points of the string, which are precursors to hadronization and rotational spectra of mesons. We further explore multi-string processes, observing the fragmentation and recombination of strings. The experimental design supports 300,000 measurement shots per circuit, totaling 600,000 shots per time step, enabling high-fidelity statistics. We employ extensive tensor network simulations using the basis update and Galerkin method to predict large-scale real-time dynamics and validate our error-aware protocols. This work establishes a milestone for probing non-perturbative gauge dynamics via superconducting quantum simulation and elucidates the real-time behavior of confining strings. [arXiv:2507.08088]