Apparently, this paper describes one of the latest breakthroughs in quantum computing developed by QuEra Computing launched on November 17, 2021!
From the company's website:
"The QuEra Approach
The company’s hardware uses arrays of neutral atoms where hundreds of atoms are cooled and then arranged by laser fields in a small vacuum chamber. While the chamber’s glass walls are at room temperature, just millimeters away the atoms are laser-cooled to a virtual standstill, reaching one millionth of a degree Kelvin above absolute zero. That is over a million times colder than deep space and over a thousand times colder than the superconducting qubits by other industry participants like IBM and Google. Unlike quantum computers based on trapped ions, which repel in close-packed quarters, QuEra’s system can arrange hundreds of neutral atoms into sub-millimeter arrays. By way of comparison to classical computing, this density is similar to the transistor density on a late 1990s Intel CPU. However, instead of connecting transistors by wires, QuEra connects its neutral-atom qubits by “Rydberg blockade.” In Rydberg blockade, laser flashes drive electrons in selected atoms to an outer orbital which causes the parent atoms to briefly “puff up” – but only on the condition that it is not blocked by another puffed up atom. This blockade forms QuEra's conditional logic gate and can happen in as short of a time period as a few nanoseconds, once again similar to a 1990s Intel CPU. However, unlike a conventional CPU, the computational power of a quantum computer is exponential in the number of qubits. QuEra has completed the construction of their first 256-qubit device which will be soon accessible to customers. ... closing in on "universal quantum computers" with thousands of logical qubits. ..."
The company’s hardware uses arrays of neutral atoms where hundreds of atoms are cooled and then arranged by laser fields in a small vacuum chamber. While the chamber’s glass walls are at room temperature, just millimeters away the atoms are laser-cooled to a virtual standstill, reaching one millionth of a degree Kelvin above absolute zero. That is over a million times colder than deep space and over a thousand times colder than the superconducting qubits by other industry participants like IBM and Google. Unlike quantum computers based on trapped ions, which repel in close-packed quarters, QuEra’s system can arrange hundreds of neutral atoms into sub-millimeter arrays. By way of comparison to classical computing, this density is similar to the transistor density on a late 1990s Intel CPU. However, instead of connecting transistors by wires, QuEra connects its neutral-atom qubits by “Rydberg blockade.” In Rydberg blockade, laser flashes drive electrons in selected atoms to an outer orbital which causes the parent atoms to briefly “puff up” – but only on the condition that it is not blocked by another puffed up atom. This blockade forms QuEra's conditional logic gate and can happen in as short of a time period as a few nanoseconds, once again similar to a 1990s Intel CPU. However, unlike a conventional CPU, the computational power of a quantum computer is exponential in the number of qubits. QuEra has completed the construction of their first 256-qubit device which will be soon accessible to customers. ... closing in on "universal quantum computers" with thousands of logical qubits. ..."
"... Some background: In 2019, Google announced that its 53-qubit machine had achieved quantum supremacy—performing a task not manageable by a convention computer—but IBM challenged the claim. The same year, IBM launched its 53-bit quantum computer. In 2020, IonQ unveiled a 32-qubit system that the company said was the “world’s most powerful quantum computer.” And just this week [46th week 2021] IBM launched its new 127-qubit quantum processor. Now QuEra claims to have made a device with far more qubits than any of those rivals." (Source)
From the abstract:
"... Here we demonstrate a programmable quantum simulator based on deterministically prepared two-dimensional arrays of neutral atoms, featuring strong interactions controlled by coherent atomic excitation into Rydberg states. Using this approach, we realize a quantum spin model with tunable interactions for system sizes ranging from 64 to 256 qubits. We benchmark the system by characterizing high-fidelity antiferromagnetically ordered states and demonstrating quantum critical dynamics consistent with an Ising quantum phase transition in (2 + 1) dimensions13. We then create and study several new quantum phases that arise from the interplay between interactions and coherent laser excitation, experimentally map the phase diagram and investigate the role of quantum fluctuations. Offering a new lens into the study of complex quantum matter, these observations pave the way for investigations of exotic quantum phases, non-equilibrium entanglement dynamics and hardware-efficient realization of quantum algorithms."
Quantum Phases of Matter on a 256-Atom Programmable Quantum Simulator (open access, preprint)
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