New Phases of Matter Explored with NISQ Computations

Abstract:

An important aspect of thermodynamics is the exploration of the phase space of matter, typically in equilibrium conditions. However, equilibrium may not be the most intriguing state of matter, as it restricts the scope for evolution and general dynamics. Unfortunately, studying non-equilibrium states is often highly complex, and our understanding of these systems remains limited. Nevertheless, driven systems provide a controlled means of operating out of equilibrium, allowing us to apply traditional thermodynamic tools alongside new methodologies to analyze their dynamics. 

In this context, NISQ (Noisy Intermediate-Scale Quantum) computers offer significant value, as they enable us to explore the quantum properties of matter in a dynamic manner. In this presentation, I will discuss the case of time crystal phases. Crystals form in space by breaking spatial translational symmetry; similarly, in the time dimension, breaking temporal translational symmetry results in a subharmonic response. In spin systems that are periodically driven at a frequency f, this manifests as an evolution at a frequency  f/2, indicating the presence of a time crystal phase. The robustness of this phase is due to many-body interactions, which create resilience against imperfect driving, ultimately producing the subharmonic response.

A NISQ machine can replicate the physics of a time crystal, allowing for the characterization of model systems involving more than 100 spins—something that is currently beyond the capabilities of classical computers.

Vita:

Nicolás Lorente obtained his Ph.D. from the Universidad Autónoma de Madrid, focusing on the physics of surfaces within condensed matter theory. His research has spanned a range of topics, including the dynamics of electronic states on surfaces, density functional theory, magnetism, correlations, and superconductivity. One of his recent projects involves creating a time crystal on a surface by positioning magnetic atoms and driving them with a scanning tunneling microscope. Thus, a comparison between NISQ results and experiments conducted at the Centro de Física de Materiales could open new avenues in both scientific understanding and methodological development.