Abstract
Quantum simulators built from ultracold atoms promise to study quantum phenomena in interacting many-body systems. However, it remains a challenge to experimentally prepare strongly correlated continuous systems such that the properties are dominated by quantum fluctuations. Here, we show how to enhance the quantum correlations in a one-dimensional multimode bosonic Josephson junction, which is a quantum simulator of the sine-Gordon field theory. Our approach is based on the ability to track the nonequilibrium dynamics of quantum properties. After creating a bosonic Josephson junction at the stable fixed point of the classical phase space, we observe squeezing oscillations in the two conjugate variables. We show that the squeezing oscillation frequency can be tuned by more than one order of magnitude, and we are able to achieve a spin squeezing close to 10 dB by utilizing these oscillatory dynamics. The impact of improved spin squeezing is directly revealed by detecting enhanced spatial phase correlations between decoupled condensates. Our work provides new ways for engineering correlations and entanglement in the external degree of freedom of interacting many-body systems.
- Received 17 April 2023
- Revised 21 December 2023
- Accepted 9 February 2024
DOI:https://doi.org/10.1103/PhysRevX.14.011049
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
Ultracold atoms serve as a well-controlled platform for quantum simulations of systems with many interacting particles. However, it remains a challenge to experimentally prepare strongly correlated continuous systems such that the properties are dominated by quantum fluctuations. In this study, we show how to prepare such a system in a regime where quantum properties, such as quantum fluctuations, dominate over thermal fluctuations.
We use two 1D quasicondensates in a double potential well to realize a bosonic Josephson junction, a microscopic system that gives rise to interesting quantum phenomena resulting from the interplay of quantum tunneling and interaction. The multimode characteristics within the quasicondensates make the system suitable as a quantum field simulator. To prepare quantum states, we split a single condensate into two and, consequently, we witness the dynamical evolution of quantum fluctuations in the relative degree of freedom between the two split condensates. We demonstrate how to use these dynamics to effectively prepare more strongly correlated quantum states and how those influence spatial phase coherence.
Our work introduces innovative methods for engineering correlations and entanglement in the external degree of freedom of interacting many-body systems. It is a leap forward in understanding and harnessing quantum correlations, paving the way for exciting possibilities in quantum simulation research.
