Bose-einstein Condensate Momentum-Selective Transport Achieved Via Controlled Non-Adiabatic Dynamics In Optical Lattices

The precise manipulation of Bose-Einstein condensates holds immense promise for quantum technologies, but achieving rapid and controlled transport remains a significant challenge. Raja Chamakhi, from LSAMA at the University of Tunis El Manar, Dana Codruta Marinica of Université Paris-Saclay, and Naceur Gaaloul from Leibniz Universität Hannover, alongside their colleagues, now demonstrate a method for swiftly moving these delicate quantum systems while maintaining a narrow range of velocities. Their research reveals how carefully timed acceleration within an optical lattice, a pattern of light used to trap atoms, allows for ‘momentum-selective’ transport, meaning the condensate moves with a predictable and focused momentum. This breakthrough, achieved through detailed simulations of atomic behaviour, identifies specific ‘magic times’ during the acceleration process where the condensate’s internal dynamics minimise unwanted spreading of momentum, enabling significantly faster coherent transport than previously possible and opening new avenues for time-sensitive quantum applications.

Fast Momentum Transfer in Optical Lattices

Researchers demonstrate a method for manipulating Bose-Einstein condensates within one-dimensional optical lattices using controlled non-adiabatic dynamics, achieving fast and momentum-selective transport. By rapidly switching the lattice potential, the team selectively excites specific momentum states, enabling targeted transport with transfer times faster than traditional adiabatic methods. The method involves applying a time-dependent modulation to the optical lattice, creating a transient tilted potential that accelerates specific momentum components of the condensate. Numerical simulations confirm that the condensate maintains coherence throughout transport, preserving its quantum properties, and that the efficiency of momentum transfer depends on modulation frequency and initial momentum distribution. This technique offers a promising pathway for manipulating quantum matter in optical lattice systems, with potential applications in quantum information processing and precision measurements.

Momentum Control via Fast Lattice Dynamics

This research presents a detailed numerical study of a protocol for momentum-selective transport of a Bose-Einstein condensate in a one-dimensional optical lattice. The protocol achieves narrow momentum distributions through controlled non-adiabatic dynamics, consisting of non-adiabatic loading, coherent acceleration using a symmetric trapezoidal profile, and non-adiabatic release. Simulations employing the time-dependent Gross-Pitaevskii equation reveal that intra-site breathing dynamics govern spectral purity under fast loading and unloading, demonstrating a pathway to precise control over the condensate’s momentum state.

Fast Atom Interferometry via Shortcuts to Adiabaticity

This research details advancements in creating and manipulating matter-wave interferometers using optical lattices, exploring methods to enhance performance for precision measurements. Researchers focus on shortcuts to adiabaticity and Floquet engineering to achieve fast, efficient, and robust control of atomic wavepackets, improving the sensitivity and stability of atom interferometers for applications like fundamental physics tests and inertial sensing. They investigate techniques to quickly and efficiently load atoms into lattices with minimal excitation, preserving coherence, and explore species-selective lattice launch. A central theme is the application of shortcuts to adiabaticity, techniques that allow for rapid changes in system parameters without exciting unwanted transitions.

Researchers explore protocols to accelerate lattice loading, transport, and manipulation, considering robustness against imperfections and noise. They also investigate time-periodic driving of optical lattices, known as Floquet engineering, to create effective potentials and band structures tailored to optimise interferometer performance, including the use of Floquet-Bloch bands to enhance transport and shaken lattices to induce Bloch oscillations. Accurate numerical simulations, employing techniques such as Fourier split-step methods and imaginary time propagation, are crucial for modelling and optimising designs.

Magic Times Control Condensate Momentum Spread

This research presents a detailed investigation into the accelerated transport of a Bose-Einstein condensate within a one-dimensional optical lattice, demonstrating a method for achieving narrow momentum distributions even with rapid changes in conditions. Through numerical simulations using the time-dependent Gross-Pitaevskii equation, scientists modelled the entire transport sequence and identified the crucial role of timing in determining the final momentum spread. The study reveals that intra-site breathing dynamics significantly influences spectral purity, and that specific loading and acceleration durations, termed “magic times”, can maximize coherence. The team demonstrated a direct correlation between the condensate’s spatial width and the final momentum spread, offering a means to infer spectral purity from real-space observations. A variational model successfully reproduced the simulation results, providing physical insight into the underlying breathing mechanism and the influence of interactions. This approach offers a pathway to rapid generation of coherent matter-wave sources, particularly relevant for applications where timing constraints preclude slower, adiabatic protocols, such as quantum sensing and interferometry.