Networks of coupled photon Bose-Einstein condensates: when condensation becomes a computation

Project Information

BEC-NETWORKS

Grant agreement ID: 101001512

DOI

10.3030/101001512

EC signature date 20 January 2021

Start date 1 February 2021

End date 31 July 2026

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 2 000 000,00

EU contribution

€ 2 000 000,00

Coordinated by

UNIVERSITEIT TWENTE
Netherlands

Periodic Reporting for period 3 - BEC-NETWORKS (Networks of coupled photon Bose-Einstein condensates: when condensation becomes a computation)

Reporting period: 2024-02-01 to 2025-07-31

Summary of the context and overall objectives of the project

Despite the significant progress in both algorithmic development and computer hardware, many computationally intensive problems remain elusive for today's most advanced computers. There's an emerging interest in alternative computational devices that diverge from the standard paradigms of digital electronic computers, aiming to bypass these challenges. Within this context, this project focuses on creating a network of coupled photon Bose-Einstein condensates, aiming to serve as an experimental platform for ultrafast simulations of classical spin systems. The primary objective is to address the ground-state problem in spin glasses, which are essentially disordered magnets. While this may sound like a niche concern, the spin glass problem is a cornerstone combinatorial challenge with implications extending to other intricate computational issues found in fields like machine learning, logistics, computer chip design, and DNA sequencing. The ultimate goal of this research is to provide a proof-of-principle demonstration, showcasing that the proposed spin glass simulator can tackle this computationally demanding optimization problem more efficiently than existing computational solutions.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The analog simulator under investigation in this project is comprised of a network of photon Bose-Einstein condensates situated within an optical microcavity formed by two mirrors. These condensates represent states of light that are similar to, but distinct from, a laser. For the experimental implementation of this system, precise control of light flow within the microcavity is paramount. This involves maintaining the relative orientation of the two mirrors, applying advanced techniques to manage the surface morphology of the mirrors, and controlling the index of refraction of the optical medium. The first half of this project has successfully tackled these challenges. Building on these techniques, the project has initiated studies on the couplings between the condensates, leading to the experimental demonstration of various coupling modalities. Such coupled condensates act as the foundational building blocks for the projected spin glass simulator.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Optical microresonators, while understood in principle for many decades, are anticipated to be central tools for exploring open quantum systems in future studies. This renewed interest is primarily due to the considerable advancements in experimental techniques for controlling such systems in recent years. This project stands at the cutting edge of this evolving field. Today, the transverse motion of photons in resonators can be controlled with remarkable precision. Photons can be confined to specific locations, manipulated to move at determined speeds, or even split and combined. Moreover, we have the capability to attenuate or amplify wavefunctions through optical gain and loss, pushing the boundaries beyond traditional Hermitian quantum mechanics. The project has already showcased the potential of creating small-scale networks of photon Bose-Einstein condensates with tunable couplings. In its next phase, the emphasis will be on scaling up this approach.

Network of 22 photon Bose-Einstein condensates simulating a two-dimensional magnet