Abstract
We design and implement a quantum annealing simulation platform to observe and study dynamical processes in quantum field theory (QFT). Our approach encodes the field theory as an Ising model, which is then solved by a quantum annealer. As a proof of concept, we encode a scalar field theory and measure the probability for it to tunnel from the false vacuum to the true vacuum for various tunneling times, vacuum displacements, and potential profiles. The results are in accord with those predicted theoretically, showing that a quantum annealer is a promising platform for encoding QFTs. This is the first time it has been possible to measure instanton processes across a freely chosen QFT energy barrier. We argue that this novel and flexible method to study the dynamics of quantum systems has potential application to many field theories of interest. Measurements of the dynamical behavior of such encoded field theories are independent of theoretical calculations and can be used to infer their properties without being limited by the availability of suitable perturbative or nonperturbative computational methods. Soon, measurements using such a quantum annealing simulation platform could therefore be used to improve theoretical and computational methods conceptually and may enable the measurement and detailed study of previously unobserved quantum phenomena.
- Received 8 July 2020
- Accepted 22 January 2021
DOI:https://doi.org/10.1103/PRXQuantum.2.010349
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Published by the American Physical Society
Physics Subject Headings (PhySH)
Popular Summary
Quantum field theories underlie the most fundamental processes in nature. They describe all the fundamental interactions via the Standard Model of particle physics, and they had a profound role in shaping the history of the early universe. Yet their complexity means that only the simplest processes can be fully understood. These are the focus of collider experiments because one can make very accurate predictions for them. On the other hand, some of the most crucial processes (e.g., quantum phase transitions) are difficult to understand analytically. They require the development of highly sophisticated mathematics.
So far no quantum laboratory has been devised that provides an experimental probe of these crucial but complicated processes. We show that a quantum annealer is exactly that—a quantum laboratory for arbitrary field theories. We take advantage of the fact that a quantum annealer is based on an Ising model; that is, an interaction model for spins, originally developed to describe ferromagnetism, but subsequently extended to more general problems. This allows us to build a framework for encoding a general field theory on a quantum annealer. We show that this framework allows one to implement and observe truly quantum dynamical, and nonperturbative, tunneling processes in an arbitrary field theory.
Thus a quantum annealer is a genuine quantum system that, following our method, can be used as a quantum laboratory for general field theories. Consequently, soon many theoretical calculations for quantum field theories could be replaced by such quantum experiments, thereby overcoming computational or theoretical limitations. This highly adaptive approach could have far-reaching implications for future studies of quantum field theories. It could even enable the measurement and detailed study of previously unobserved quantum phenomena that are relevant for field theories of interest in particle physics, condensed matter physics, quantum optics, or cosmology.
