Global celebration greeted the 2012 discovery at CERN’s Large Hadron Collider of a particle that matches the textbook description of the Higgs boson. That achievement validated a remarkable chain of theoretical reasoning that combined the notion that symmetries dictate interactions with lessons from superconductivity. It was enabled by triumphs of accelerator art and experimental technique, and by human resourcefulness and collaboration on a global scale.

Some imagine that, once the keystone of the standard model of particle physics has been set, our subject is over. Others worry that we may be at an impasse, without sharp clues to a more complete understanding. I prefer to savor the challenge that our description of nature is incomplete, that we have so much more to learn.

This colloquium surveys themes that explore the breadth and depth of opportunities to enhance our understanding of the physical world, illustrated by examples from my research.

Quantum fluids and solids (QFS) exhibit remarkable macroscopic quantum phenomena and provide exceptionally clean environments for exploring fundamental physics and developing emerging quantum technologies. Superfluid helium-4 (He II), for example, supports frictionless superflow and quantized vortices, while cryogenic surfaces such as liquid helium and solid neon can naturally trap electrons in vacuum with minimal environmental disturbance. In this colloquium, I will discuss our efforts to explore and harness these unusual properties of cryogenic quantum matter. I will begin by introducing He II as a model quantum fluid and describing advanced flow-visualization techniques that allow us to directly probe quantized vortex dynamics, quantum turbulence, and related nonequilibrium phenomena. I will highlight our recent studies of vortex reconnections, quantum dissipation associated with vortex rings, and coherent vortex structures. I will then turn to emerging opportunities for using quantum fluids as platforms for quantum sensing, including our recent work with magnetically levitated He II droplets. Finally, I will discuss our efforts to develop qubits based on single electrons trapped on solid neon surfaces. Recent electron-on-neon experiments have demonstrated excellent coherence, but scaling the platform to larger and more controllable qubit arrays remains a major challenge. I will describe a new architecture based on magnetically levitated solid-neon microparticles that may offer a pathway toward scalable electron-qubit systems. Together, these studies illustrate how quantum fluids and solids can bridge fundamental discoveries in macroscopic quantum physics with emerging opportunities in quantum science and technology.