The goal of the quantum computing community has been to develop what are called “universal quantum computers.” These devices are all intended to run the same standard algorithms, such as Grover’s Algorithm, Quantum Phase Estimation (QPE), and Shor’s Factoring Algorithm. They’re compared, generally, on factors related to their ability to do so qualitatively: coherence times, gate execution speeds, and single-qubit and multi-qubit operation errors.
But not every quantum computer architecture is the same. Without getting technical, a quantum computer hardware architecture based on nitrogen vacancy centers can fit within a standard server rack in a datacenter, while an ion trap architecture requires an estimated 200 ft2 of floor space. Even within the same modality, the quantum computer design can vary substantially. For example, cat qubits are superconducting qubits, but they’re resilient to one of the two major types of errors. Furthermore, even the term “neutral atom” can refer to different species of atoms.
Among all the modalities currently in development and being researched, a quantum computer architecture based on neutral atoms offers a few key advantages. Some of these advantages are shared with other modalities. However, no other modality shares all of the following advantages:
Having briefly mentioned atomic clocks, it is worth noting that neutral atoms have applications beyond quantum computing. For another example, neutral atoms are used in various quantum sensors, such as portable, highly-sensitive gravimeters.
The advantages of using neutral atoms are not just nice to have. In fact, qualitative benefits can be derived from them. Diving a little deeper into these advantages, some of the potential benefits of neutral atom architectures include:
These benefits help to illustrate why neutral atom quantum computing is gaining in popularity. The availability of the 256-atom “Aquila” device was recently extended – almost quintuple its initial availability – in response to public demand.
The components of quantum computing vary wildly depending on what is being used as a qubit. For that matter, they can vary quite a bit using the same qubit. At a very high level, a sampling of the variation out there includes:
Other architectures are in development, and may vary even more wildly than these. Electron traps, for example, combine the vacuum chambers of ion traps with the microwave controls and dilution refrigeration of superconducting architectures. But then there are topological qubits, which don’t closely resemble any of the other modalities. Furthermore, research into other novel modalities may be as yet unpublished.
An SDxCentral article titled “Inside quantum computing architecture,” despite its generic title, provides further detail specifically into superconducting architectures. Because they leverage existing knowledge of semiconductor fabrication, this architecture is currently the most common. It’s not without its challenges, however. As already noted, despite this semiconductor experience, the largest publicly-available quantum computer in the world is the 256-atom “Aquila.” Also, the article mentions the glass enclosures of superconducting architectures. These glass enclosures, as well as the space surrounding these glass enclosures and the space for the control systems, adds up to a significant footprint. In some cases, an entire room with a side closet is dedicated to a single superconducting quantum computer.
An article by Red Hat titled “An introduction to quantum computing architecture” compares in-house quantum computers to the early days of classical computing. However, any discussion of quantum computing infrastructure should include all the technology to make it cloud accessible. Whether or not they are publicly-accessible, many quantum computers are cloud-accessible. In our article titled “Exploring the Advantages of Cloud-Based Quantum Computing,” we go into detail as to why that is the case.
Finally, our article titled “Quantum Computer Technology: Architecture, Advantages and Disadvantages” further explores the advantages and disadvantages of quantum computing technology. It differs from this article in that its more generic, whereas this article delves more specifically into neutral atom architectures.
For technical insights into neutral atom architectures, be sure to check out the learning resources for the Bloqade and Bloqade-Python libraries. Because operation is currently analog, soon to be hybrid digital-analog, these resources go into detail about atom positioning, pulse shapes and durations, and so forth. These resources include recordings of training sessions, during which an expert instructor explains the operations of the device and answers trainee questions.