Researchers at Rice University and Durham University have developed a ‘magic trap’ that prolongs quantum behavior in an experimental system by nearly 30 times. The team, led by Kaden Hazzard and Simon Cornish, used ultracold temperatures and laser wavelengths to delay the onset of decoherence, a process that causes quantum effects to vanish. The molecules were cooled to a billion times below room temperature and set to rotate quantum mechanically using microwave radiation. The ‘magic trap’ kept the molecules rotating for nearly 1.5 seconds, a 30-fold increase, allowing scientists to study fundamental questions about interacting quantum matter.
Quantum Technologies and Their Challenges
Quantum technologies, with their potential to revolutionize computing, drug development, and sensing applications, are a hot topic in the scientific community. However, studying quantum behaviors experimentally presents a significant challenge. Most systems can only sustain quantum effects for a short time due to a process called decoherence. As Kaden Hazzard, associate professor of physics and astronomy at Rice University, explains, decoherence occurs when a quantum system interacts with its surroundings, causing it to behave in a classical, non-quantum fashion. This interaction limits the ability to investigate phenomena at the quantum level.
The ‘Magic Trap’ and Prolonging Quantum Behavior
A recent study published in Nature Physics, authored by Hazzard and his team at Rice University, along with collaborators from Durham University in the United Kingdom, has made a significant breakthrough in prolonging quantum behavior. The researchers were able to extend the duration of quantum behavior in an experimental system nearly 30-fold by using ultracold temperatures and laser wavelengths to generate a “magic trap” that delayed the onset of decoherence. This is the first experimental demonstration of its kind and opens a new arena to study quantum interactions.
Ultracold Molecules and Quantum Rotation
The research teams at Rice and Durham Universities cooled molecules to a billion times below room temperature to create a unique quantum mechanical system. They then used microwave radiation to set these molecules to rotate quantum mechanically, a situation analogous to molecules aligning and rotating both clockwise and counterclockwise simultaneously. Simon Cornish, from Durham University, explains that at these extremely low temperatures, atoms or molecules can be controlled with light, allowing for a level of precision and control not normally achievable.
The ‘Magic’ Wavelength and Quantum Coherence
The coherence of this rotating behavior in the ultracold molecules typically decays over a very short amount of time. However, inspired by theoretical work by Svetlana Kotochigova from Temple University, Cornish’s group suggested that a certain “magic” wavelength of light could preserve quantum coherence for a longer period. When this theory was applied in the laboratory, the researchers created a “magic trap” that kept the molecules rotating quantum mechanically for nearly 1.5 seconds, a 30-fold increase from the previous record of 1/20 of a second.
Implications for Quantum Technologies
Zewen Zhang, a graduate student in Hazzard’s group, believes that improved coherence times will allow scientists to study fundamental questions about interacting quantum matter. As coherence times become longer, new effects are unveiled, and scientists can begin exploring by comparing experimental measurements to calculations. Improved coherence is also a step towards using ultracold molecules as a platform for various quantum technologies. Hazzard, a member of the Rice Quantum Initiative and the Smalley-Curl Institute, adds that understanding what is happening at the quantum level is crucial for developing new materials, sensors, and other quantum technologies.
Funding and Support
The research was supported by several institutions, including the U.K. Engineering and Physical Sciences Research Council, U.K. Research and Innovation Frontier Research Grant, the Royal Society, Durham University, the Robert A. Welch Foundation, the National Science Foundation, the Office of Naval Research, the W.F. Keck Foundation, and the U.S. Air Force Office of Scientific Research.
“The reason why quantum physics’ mysterious features tend to vanish so quickly is a process called decoherence,” said Kaden Hazzard, associate professor of physics and astronomy at Rice University and a corresponding author on a study published in Nature Physics. “It occurs when a quantum system interacts with its surroundings and this changes the physics. The bigger the system and the larger the couplings to the surroundings, the more the system will behave in a classical, non-quantum fashion ⎯ and you lose your ability to investigate things at the quantum level.”
“When you cool atoms or molecules to these extremely low temperatures, you can control them with light,” Cornish said. “You can actually use lasers to push on the atoms and make them go where you want them to go. You can also use lasers to trap or hold them, and that gives you a level of precision and control that you wouldn’t have normally.”
“Quantum behavior becomes more prominent the colder the system is and brings the quantum behavior to larger length scales,” said Jonathan Stepp, a graduate student in Hazzard’s group. “And having lasers at the right wavelength can ‘trap’ the molecules, so they can rotate in lockstep, which preserves the quantum coherence for a longer time.”
“While I’m not surprised it worked, I’m definitely surprised at how well it worked,” Hazzard said.
“As coherence times become longer, new effects are unveiled,” Zhang said. “We can begin exploring by comparing the experimental measurements to our calculations. Improved coherence is also a step to using ultracold molecules as a platform for various quantum technologies.”
“Even though quantum behavior sounds like a very exotic thing, it’s actually responsible for things we see every day, from how metals conduct electricity to how fusion is produced by the sun,” added Hazzard, who is a member of the Rice Quantum Initiative and the Smalley-Curl Institute. “If you want to make new materials, new sensors or other quantum technologies, you need to understand what is happening at the quantum level, and this research is a step toward achieving new insights.”
Quick Summary
Scientists at Rice University and Durham University have developed a method to prolong quantum behaviour in an experimental system by nearly 30 times, using ultracold temperatures and laser wavelengths to create a ‘magic trap’ that delays the onset of decoherence. This breakthrough, which allows molecules to rotate quantum mechanically for significantly longer periods, opens up new possibilities for studying quantum interactions and advancing quantum technologies.
- Researchers at Rice University and Durham University have made a significant breakthrough in quantum technology by prolonging quantum behaviour in an experimental system nearly 30-fold.
- The team, led by Kaden Hazzard at Rice and Simon Cornish at Durham, used ultracold temperatures and laser wavelengths to create a ‘magic trap’ that delayed the onset of ‘decoherence’, a process that causes quantum effects to vanish quickly.
- The researchers cooled molecules to a billion times below room temperature to create a unique quantum mechanical system, then used microwave radiation to set these molecules to rotate quantum mechanically.
- The ‘magic trap’ kept the molecules rotating quantum mechanically for nearly 1.5 seconds, a 30-fold increase from the previous record of 1/20 of a second.
- This improved coherence time will allow scientists to study fundamental questions about interacting quantum matter and could potentially lead to advancements in quantum technologies.
- The research was supported by various institutions including the U.K. Engineering and Physical Sciences Research Council, the Royal Society, Durham University, the Robert A. Welch Foundation, the National Science Foundation, the Office of Naval Research, the W.F. Keck Foundation and the U.S. Air Force Office of Scientific Research.