Giant atoms ‘trapped’ for record time at room temperature

Giant atoms have emerged as strong contenders for creating advanced quantum simulators and computers, as researchers have achieved unprecedented control over them for an extended period in a room-temperature experiment.

By manipulating atoms and adjusting their quantum properties using electromagnetic pulses or laser light to alter the energies of their electrons, these atoms can be utilized to encode information. When this process is applied to thousands of atoms, it paves the way for the development of quantum computers or simulators for studying complex quantum materials. However, the challenge lies in the fact that atoms tend to undergo spontaneous state changes over time, leading to errors. The usefulness of these atoms is limited by their finite “lifetime”, which has previously been capped at 1400 seconds for room-temperature experiments. While scientists have managed to trap atoms for longer durations, these methods often required the entire setup to be housed in a large refrigerator, presenting logistical hurdles.

Zhenpu Zhang and Cindy Regal from the University of Colorado Boulder, along with their team, have broken the room-temperature record by employing Rydberg atoms, which are characterized by their oversized diameter due to the electrons being situated far from the nuclei. The researchers placed these atoms in a container devoid of any air particles that could disrupt them, and then used lasers or “optical tweezers” to manipulate each atom. This method is commonly used to control Rydberg atoms, given their high sensitivity to electromagnetic fields and light.

Additionally, the researchers lined the container’s walls with a layer of copper, which was cooled to -269°C (-452°F). This coating served to shield the atoms from heat-induced state changes. Zhang explained that any stray air particles were attracted to the copper surface, akin to how warm water droplets condense on a cold object, thereby enhancing the vacuum within the container. As a result, the team succeeded in trapping and maintaining control over the atoms for approximately 50 minutes – equivalent to 3000 seconds, or roughly double the duration achieved in previous similar experiments.

Regal mentioned that Zhang had been working on developing this setup from scratch for about five years. She stated, “This is like a total overhaul in terms of how you approach designing these experiments.”

Clément Sayrin from the Kastler Brossel Laboratory in France lauded the new approach, highlighting its potential to enable the manipulation of a larger number of atoms, thereby boosting the computational power of any computer or simulator built using these atoms. Sayrin remarked, “Three thousand seconds is a significant duration. Achieving such long lifetimes for these atoms requires dedicated efforts.” However, he noted that incorporating more atoms into the chamber would necessitate the use of additional lasers for control, which might diminish the atoms’ lifetimes, indicating that there are still engineering challenges to address.