Two dimensional arrays of Bose-Einstein condensates: interference and stochastic collapse dynamics (2404.14142v1)

Abstract: We demonstrate two-dimensional arrays of Bose-Einstein condensates (BECs) as a new experimental platform with parallel quantum simulation capability. A defect-free array of up to 49 BECs is formed by loading a single BEC with 50,000 atoms into 7*7 optical wells. Each BEC is prepared with independent phases, confirmed by matterwave interference. Based on BEC arrays, we realize fast determination of the phase boundary of BECs with attractive interactions. We also observe the stochastic collapse dynamics from the distribution of atom numbers in the array. We show that the collapse of a BEC can occur much faster than the averaged decay of an ensemble. The BEC arrays enable new forms of experiments to drastically increase the measurement throughput and to quantum simulate, say, large 2D Josephson-junction arrays.

• The paper presents a defect-free 2D BEC array platform that enables parallel quantum simulation experiments.
• It verifies phase-independent matter-wave interference and accurately maps stability boundaries with a critical parameter near 0.51.
• It uncovers rapid stochastic collapse dynamics, providing fresh insights into managing decay in quantum condensates.

Overview of Two-Dimensional Bose-Einstein Condensate Arrays

This paper presents an investigation into two-dimensional arrays of Bose-Einstein Condensates (BECs), leveraging them as a powerful platform for parallel quantum simulations. This notable work introduces a defect-free assembly of up to 49 BECs, providing a new experimental structure significant for advancing quantum simulation techniques. The paper explored several key concepts, including matter-wave interference, phase boundary determination for BECs with attractive interactions, and stochastic collapse dynamics.

The researchers employed optical tweezer arrays to prepare 7×7 matrices of BECs, each containing approximately 1,000 to 2,000 atoms. The assembly was achieved by distributing a single parent BEC with 50,000 atoms into optical wells. A significant aspect of the experiment was phase coherence confirmation via matter-wave interference, which established that these BECs held independent phases post-distribution.

Interference and Phase Independence

One of the paper's crucial demonstrations was the matter-wave interference among the BECs. By examining the interference patterns during time-of-flight expansion, it was determined that the BECs exhibited random phases, verified through both experimental measurements and Gross-Pitaevskii equation simulations. The interference fringes exhibited a wave vector consistent with theoretical predictions, affirming the physical behavior of the BECs in handling random phases. This independence in phases is vital for various applications in quantum simulations, like modeling large 2D Josephson-junction arrays.

Phase Boundary Mapping

Utilizing the unique capabilities of BEC arrays, the paper accelerated the determination of stability phase diagrams for BECs with attractive interactions. By deploying parallel experiments across the array with varying atom numbers and scattering lengths, the team identified the phase boundary where BECs transition from stability to collapse. This was conducted efficiently within a single experimental cycle, marking a significant improvement over traditional repetitive experimental approaches. The findings were consistent with theoretical predictions, with a reported critical condition parameter, $\kappa$, determined to be approximately 0.51.

Stochastic Collapse Dynamics

Another significant element of the research was the exploration of the stochastic dynamics related to the collapse of BECs. Near the stability boundary, fluctuations in atom numbers implied a stochastic nature of collapse, characterized by a delay time followed by an exponential decay. The team modeled this process and identified a fast decay time constant, suggesting the collapse dynamics occurs on a much shorter timescale than previously averaged ensemble decay measurements. This insight into the decay dynamics offers practical understanding for navigating the metadynamics of BECs in condensed matter simulations and potentially other related quantum systems.

Implications and Future Directions

The implications of this research are two-fold, both practical and theoretical. Practically, the development of BEC arrays facilitates high-throughput and parallel experimentation, expanding prospects in quantum simulation and information processing. Theoretically, it provides a robust framework for studying interactions within multi-BEC systems, and the stochastic nature of quantum condensates, pushing the boundaries of our understanding of quantum degeneracy and coherence phenomena.

Looking forward, the paper suggests that deploying larger arrays could further enhance simulation capacities in quantum research, with improvements both in the number of BECs and precision of phase and dynamic controls. This work lays the foundation for future explorations into complex systems that leverage the fine control of optical tweezer arrays, potentially ushering new advances in quantum computing and metrology.

Overall, this paper successfully underscores the integration of optical and quantum principles to advance the utility of Bose-Einstein condensates in experimental physics, reinforcing the practical importance of this quantum state and offering fresh insights into its manipulation and application.