JA 7.07, Department of Physics,
University of Strathclyde,
107 Rottenrow, Glasgow, G4 0NG, Scotland, U.K.
Telephone: +44 141 548 4652
Fax: +44 141 552 2891
THE MANY BODY PROBLEM
I am interested in the quantum many body problem, how is it possible that the same constituents atoms, when joined together in different scenarios produce such a beautiful and diverse world? This is a consequence of collective emergence a field of study that is relevant to diverse disciplines such as condensed matter physics (think of superconductors), high energy physics (think of quark confinement), quantum information (think of topological quantum computers) and ultimately quantum gravity (think of the emergence of space and time).
Entanglement was originally introduced in the context of the foundation of quantum mechanics, and it encodes the fact that the evolution of a composite system cannot be described as the consequence of the separate evolution of its constituents. Nowadays entanglement provides a unifying framework to quantitatively describe emergence.
Tensor networks provide an ansatz for the wave function of many body systems based on the contraction of a network of small constituent tensors. They can be used both as a numerical tool to compute the low energy states of some interesting Hamiltonian, but they also constitute a completely new theoretical framework where one can develop the theory of many body systems
Alternatively one can try to artificially mimic nature, by experimentally engineer some exotic emerging phenomena using ultra-cold atoms or trapped-ions interacting with light. This allows to implement a hands-on approach on emergence, and observe experimentally emerging phenomena in different context from those in which they physically arise, and thus simulate nature using quantum building blocks
Gauge symmetry seems to be one of the underlying principles responsible for interactions. Gauge theories provide concrete examples of collective emergence that we still do not completely understand. I work to extend tensor networks and quantum simulations so to be able to apply them to gauge theories.
While we can characterize emergence in a unified way through entanglement, it is very difficult to measure it in experiment, wouldn’t it be great to be able to detect exotic emerging phenomena in experiments by measuring the underlying entanglement?