papers

Publications (16)

quant-ph2024

Capturing long-range memory structures with tree-geometry process tensors

Neil Dowling, Kavan Modi, Roberto N. Muñoz +2

We introduce a class of quantum non-Markovian processes -- dubbed process trees -- that exhibit polynomially decaying temporal correlations and memory distributed across time scale…

quant-ph2026

Diagnosing chaos with projected ensembles of process tensors

Peter O'Donovan, Neil Dowling, Kavan Modi +1

The process tensor provides a general representation of a quantum system evolving under repeated interventions and is fundamental for numerical simulations of local many-body dynam…

quant-ph2026

Page Curve for Local-Operator Entanglement from Free Probability

Neil Dowling, Silvia Pappalardi

The local-operator entanglement (LOE) measures the classical simulability of a Heisenberg operator and is conjectured to witness many-body chaos in locally interacting systems. Usi…

quant-ph2025

Free Independence and Unitary Design from Random Matrix Product Unitaries

Neil Dowling, Jacopo De Nardis, Markus Heinrich +2

Unitary randomness underpins both fundamental tasks in quantum information and the modern theory of quantum chaos. On one side, a central concept is that of approximate unitary des…

quant-ph2020

Second law of thermodynamics for relativistic fluids formulated with relative entropy

Neil Dowling, Stefan Floerchinger, Tobias Haas

The second law of thermodynamics is discussed and reformulated from a quantum information theoretic perspective for open quantum systems using relative entropy. Specifically, the r…

quant-ph2025

Bridging Entanglement and Magic Resources within Operator Space

Neil Dowling, Kavan Modi, Gregory A. L. White

Local-operator entanglement (LOE) dictates the complexity of simulating Heisenberg evolution using tensor network methods, {and bears witness to many-body chaos for local dynamics}…

quant-ph2026

Noise-induced Simulability Transition from Operator Scrambling

Neil Dowling, Xhek Turkeshi, Jacopo De Nardis +1

The complexity of simulating quantum many-body dynamics, or quantum computations, in the Heisenberg picture is governed by the scrambling of initially simple operators into superpo…

quant-ph2024

Operational Metric for Quantum Chaos and the Corresponding Spatiotemporal Entanglement Structure

Neil Dowling, Kavan Modi

Chaotic systems are highly sensitive to a small perturbation, and are ubiquitous throughout biological sciences, physical sciences and even social sciences. Taking this as the unde…

quant-ph2025

Stabilizer Tensor Networks with Magic State Injection

Azar C. Nakhl, Ben Harper, Maxwell West +4

This work augments the recently introduced Stabilizer Tensor Network (STN) protocol with magic state injection, reporting a new framework with significantly enhanced ability to sim…

quant-ph2023

Scrambling is Necessary but Not Sufficient for Chaos

Neil Dowling, Pavel Kos, Kavan Modi

We show that out-of-time-order correlators (OTOCs) constitute a probe for Local-Operator Entanglement (LOE). There is strong evidence that a volumetric growth of LOE is a faithful…

quant-ph2026

Classical Simulability from Operator Entanglement Scaling

Neil Dowling

Local-operator entanglement (LOE) quantifies the nonlocal structure of Heisenberg operators and serves as a diagnostic of many-body chaos. We provide rigorous bounds showing when a…

quant-ph2025

Magic Resources of the Heisenberg Picture

Neil Dowling, Pavel Kos, Xhek Turkeshi

We study a non-stabilizerness resource theory for operators, which is dual to that describing states. We identify that the stabilizer Rényi entropy analog in operator space is a g…

quant-ph2023

Equilibration of Multitime Quantum Processes in Finite Time Intervals

Neil Dowling, Pedro Figueroa-Romero, Felix A. Pollock +2

A generic non-integrable (unitary) out-of-equilibrium quantum process, when interrogated across many times, is shown to yield the same statistics as an (non-unitary) equilibrated p…

quant-ph2026

Adversarial Robustness Guarantees for Quantum Classifiers

Neil Dowling, Maxwell T. West, Angus Southwell +4

Despite their ever more widespread deployment throughout society, machine learning algorithms remain critically vulnerable to being spoofed by subtle adversarial tampering with the…

quant-ph2025

A graph-theoretic approach to chaos and complexity in quantum systems

Maxwell West, Neil Dowling, Angus Southwell +4

There has recently been considerable interest in studying quantum systems via dynamical Lie algebras (DLAs) -- Lie algebras generated by the terms which appear in the Hamiltonian o…

quant-ph2023

Relaxation of Multitime Statistics in Quantum Systems

Neil Dowling, Pedro Figueroa-Romero, Felix A. Pollock +2

Equilibrium statistical mechanics provides powerful tools to understand physics at the macroscale. Yet, the question remains how this can be justified based on a microscopic quantu…