Tuesday, August 23, 2022

Quantum Gate 100x Faster Than Quantum Noise

Amazing stuff! Physics at the extremes!

"... Now scientists in Japan have successfully executed an operation with two qubits in just 6.5 nanoseconds—the fastest ever, which may essentially outrun the effects of any outside interference. ...
However, quantum computers are notoriously fragile to outside interference, such as electronic, ionic, or thermal fluctuations. This means present-day state-of-the-art quantum computers are highly prone to mistakes, typically suffering roughly one error every 1,000 operations. ...
“We can manipulate [neutral atom qubits] on completely new timescales, and it redefines what can be done with this platform.” ...
One way to deal with the effects of noise in quantum computers is to speed up the rate at which they perform elementary operations known as quantum gates—the quantum-computing version of the logic gates that conventional computers use to perform computations. The chance that a quantum gate will experience a mistake from noise grows over time, so the faster they operate, the lower the probability they will fail. ...
In the new study, researchers experimented with qubits composed of neutrally charged rubidium atoms. Neutral atoms may possess a number of benefits as qubits in comparison with other quantum computing platforms. ...
In addition, the fact that neutral atoms lack electric charge means they do not interact easily with other atoms. ...
The scientists first trapped and cooled neutral atoms with arrays of laser beams. They next used these lasers to excite electrons to so-called Rydberg orbitals far from their atomic nuclei. The resulting “Rydberg atoms” can be hundreds to thousands of times as large as the atoms would be in their ground states. ...
In the new study, the researchers used laser beams to control the distance between atoms with a precision of 30 nanometers. They also cooled the atoms to an ultralow temperature about 1/100,000 of a degree above absolute zero, to reduce any jittering from heat.
The researchers next used ultrashort laser pulses that lasted just 10 picoseconds—trillionths of a second—to excite a pair of these atoms to a Rydberg state at the same time. This let them execute a quantum gate entangling the qubits in just 6.5 ns, making it the fastest quantum gate to date. (The previous speed record for a quantum gate was 15 ns, achieved by Google in 2020 with superconducting circuits.) ..."

Quantum Gate 100x Faster Than Quantum Noise - IEEE Spectrum Superfast operations may help neutral-atom-based machines outrun disruptions


Fig. 1: Ultrafast Rydberg platform.


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