QUANT26: Quantum Dynamics - Fundamentals and Realizations

The rapid development of commercially available quantum devices is providing the research community with powerful new tools for exploring a broad range of topics in quantum physics. In this talk, I will outline our recent results on open-system atomic physics and coherent many-body dynamics using QuEra’s analog quantum simulator based on neutral-atom Rydberg arrays. First, I will discuss collective loss phenomena in Rydberg atoms. Our observations show that Rydberg atom loss depends strongly on the size and geometry of the array, suggesting that interactions and correlated processes play an important role beyond independent single-atom decay. Measurements of loss rates and spatial loss correlations place strong constraints on the mechanisms underlying the observed many-body loss dynamics. Next, I will switch gears and discuss how the same platform can be used to investigate many-body behavior in Ising models. By varying the detuning and amplitude of the Rydberg drive, we map out the phase diagram of the mixed-field Ising system and examine universal critical behavior near a continuous phase transition. Such universality connects systems with vastly different microscopic details.

abstract

Artificial Intelligence (AI) is everywhere, but getting a model from notebook to production is another story — most projects never make it. I will outline the main obstacles data science teams face in industry, walk through concrete use cases from AI products we currently ship, and show where physics training — rigor, modeling intuition, comfort with uncertainty — gives you a real edge in tackling them.

While an interacting quantum many-body system typically evolves toward a state of thermal equilibrium, strong disorder can theoretically suppress this thermalization process through a phenomenon known as many-body localization (MBL). Despite experimental observations, the nature of MBL as a quantum phase has remained unclear, particularly for high-dimensional systems. Understanding this long-standing problem requires resolving the microscopic mechanisms behind localization, an ideal task for programmable quantum processors. Here, we emulate the dynamics of a disordered two-dimensional Floquet Ising model using 105 superconducting qubits. Utilizing multi-qubit and non-local correlation measurements, we first observe integrals of motion indicative of an MBL regime at strong disorder. Next, focusing on the boundary between MBL and ergodic regimes, we uncover multiple critical behaviors reminiscent of a quantum phase transition. These include a sharp crossing of the Edwards-Anderson order parameter between different system sizes when measured over the effective disorder strength, a maximal sensitivity of spatial correlations to disorder details and a persistent dynamical fluctuation of resonant clusters. Lastly, we test the stability of 2D MBL by implanting an ergodic region. Up to 200 Floquet cycles, the thermalization effect of the ergodic region is found to propagate more slowly in two dimensions than in one. These results indicate that, within experimental time scales, the two-dimensional Floquet Ising model exhibits signatures of a non-equilibrium quantum phase.

The Streda formula provides a remarkable connection between a simple thermodynamic response and the topological properties of quantum matter, relating the quantized Hall conductivity of an insulator to its density response under an external magnetic field. This lecture uses the Streda formula as a guiding thread to connect the quantum Hall effect, Chern insulators, and Floquet topological phases, showing how a simple density response provides physical insight into increasingly rich forms of topological quantum matter. Starting from the integer quantum Hall effect, we will develop an intuitive understanding of the Streda relation through Landau levels, spectral flow, and general thermodynamic arguments, before extending it beyond Landau quantization to lattice realizations of quantum Hall physics, such as Chern insulators. In this broader setting, the magnetic-field-induced density response acquires the interpretation of a local topological marker, providing experimentally accessible signatures of topology even in disordered and spatially inhomogeneous systems. The second part introduces Floquet engineering, where periodic driving is used to realize effective Hamiltonians with properties inaccessible in equilibrium. This naturally leads to Floquet topological phases, including anomalous edge states that challenge the conventional classification of static systems. Building on the Streda framework, we will show how the winding invariants characterizing Floquet phases can be understood from simple physical response principles, providing a physical perspective on the origin of their anomalous edge states.

The steady interest in understanding the thermodynamics of quantum systems has led to several approaches to defining work and heat in a quantum mechanically consistent way. Quantum thermodynamics as a subfield has grown steadily in the last 15 years, revealing the impact that coherence can have on the energetics of quantum systems. I will initially aim to provide an overview of some of the major lines of inquiry in the field, briefly discussing commonly employed definitions of quantum work, its experimental measurement, and some proof-of-principle demonstrations of nano-scale quantum heat engines. We will then zero in on some exciting new directions that the community has begun to explore, as recently collated in Ref [1]. We will aim to touch on the full breadth of applications, ranging from the foundational aspects, e.g. information propagation and scrambling which lie at the interface of quantum information and high energy physics, to the practical ramifications of the theory, which is driving the design of energetically efficient quantum technologies. [1] Roadmap on Quantum Thermodynamics, S. Campbell et al, Quantum Sci. Technol. 11, 012501 (2026).

In this lecture, I shall present some important ideas from the field of quantum magnetism. I shall begin with basic energetics, and then proceed to the notion of geometrical frustration and its consequences, before connecting these to more modern concepts such as deconfined quantum criticality. The emphasis will be on back-of-the-envelope and pictorial arguments that get across the essence of the physics under discussion.

Programmable quantum simulators are rapidly evolving from proof-of-principle devices into experimental platforms for exploring and controlling many-body physics. Their openness to the environment, finite coherence times, and device imperfections are usually treated as obstacles to be overcome. We will see how some of these apparent bugs can instead become features: noise and metastability can be exploited, while initial-state engineering can be used to access regimes and dynamical phenomena that would otherwise remain out of reach. I will show how present-day quantum platforms can be “hacked” beyond their original scope, turning imperfect devices into versatile laboratories for probing relaxation, criticality, and the limits of control.