Physicists in Germany built atoms 10,000 times larger than normal, held them steady at room temperature, and still broke three world records that usually demand near-absolute-zero cooling.
- 3 world records set in a single experiment
- 20x longer atom stability than comparable free-space measurements
- 11 milliseconds the excited circular state survived
- 133 milliseconds the atom stayed held in a laser trap
Why "Giant" Atoms Matter
The team, based at the University of Stuttgart's 5th Institute of Physics, worked with circular Rydberg atoms — atoms with an electron pushed into a wide, circular orbit far from the nucleus. That pushes the atom's effective size to roughly 10,000 times that of an ordinary atom, letting it interact with neighboring atoms across distances of about 5 micrometers, large enough for lasers to address and control individually.
That property makes Rydberg atoms attractive building blocks for quantum simulators — devices that recreate quantum systems scientists want to study, and test beds for techniques future quantum computers will need. The problem has always been durability: Rydberg atoms are so sensitive to their surroundings that they typically survive only briefly before environmental noise knocks them out of their excited state.
"One major challenge in developing high-performance quantum simulators was that Rydberg atoms are highly sensitive and remain stable for only a short time," said Prof. Tilman Pfau, who leads the institute.
"We overcame this challenge and increased the stability of the atoms by a factor of 20."
Blocking Microwaves Instead of Cooling the Atoms
The three records, published in Nature Communications, cover the longest lifetime ever measured for an individual Rydberg atom, the largest circular Rydberg atom controlled in a lab, and the longest time such an atom has been held in an optical tweezer — a focused laser beam used to trap and position single atoms.
Normally, achieving that kind of stability requires liquid-helium cooling to suppress the thermal microwave radiation that surrounding surfaces emit at room temperature, radiation that easily disturbs an atom's delicate excited state. The Stuttgart group, led by Dr. Florian Meinert, instead revived a shielding technique from the 1980s: placing the atoms between two transparent, electrically conductive plates that block the interfering microwaves without any cryogenic cooling at all.
"We achieved these record results at room temperature without the costly liquid helium cooling previously required," Meinert said, according to details compiled by the 5th Institute of Physics.
What a Longer-Lived Atom Buys You
More milliseconds of stability translate directly into more computational steps a quantum simulator can perform before noise wrecks the result — the physical equivalent of extending a computer's attention span. Longer-lived states also allow researchers to control interactions between atoms with greater precision, a prerequisite for scaling neutral-atom systems into larger, more capable machines.
The Stuttgart team says its room-temperature circular-Rydberg platform is now unique worldwide, and the group plans to use it to push toward full quantum simulators, quantum computers and ultra-precise quantum sensors — all without the helium dewar that has defined this corner of physics for decades.
