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A Neutral Atom Quantum Computer: From Nobel Prize to Reality

January 26, 2023 by Jake Hertz

Pasqal, a company based on Nobel Prize-winning research, has recently secured over $100M in funding to progress its neutral atom architecture. With the field of quantum computing still in its infancy, researchers are attempting to scale up quantum technology using several different methods. The feasibility of quantum computers is still mostly conjecture since no existing devices have proven the commercial advantages of classical computers yet. Paris-based quantum computer company Pasqal hopes to change that with a new approach to quantum computing they believe will offer commercial advantages over classical computers by 2024. Pasqal recently secured €100M ($108.6 USD) in funding to further bolster these efforts.

Rendering of the inside of one of PASQAL's quantum computers. Image courtesy of Pasqal

In this article, we’ll take a look at conventional approaches to qubits, Pasqal’s neutral atom technology, and the details of the startup's new funding round.

What Is Neutral Atom Quantum Computing?

While quantum computing typically involves superconducting circuits or silicon spin qubits, Pasqal's hardware is based on neutral atom quantum computing, a concept that is directly derived from Nobel Prize-winning research

In neutral atom quantum computing, arrays of single neutral atoms are manipulated by light beams to encode and read out quantum states. In these types of quantum processors, a qubit is defined by one of two electronic states of an atom, and these single neutral atoms are arranged in configurable arrays. In this architecture, arrays are analogous to classical registers, where each atom plays the role of a single qubit.

A system diagram of a PASQAL’s neutral atom quantum computer. Image courtesy of Quantum

In most real-world applications, Pasqal's element of choice is rubidium, a common element in atomic physics that has been long-investigated and well understood. Since atoms technically can occupy an infinite number of electronic states, two specific electronic levels must be defined for the architecture, representing 0 and 1.

Pasqal uses light as the main tool to control both the position and the quantum state of the atoms; the light of different wavelengths can force the neutral atoms into different states. These processors require both lasers and electronic controls to tune the light properties, apply instructions from the quantum software stack, and extract information through atomic detection.

Neutral atom quantum computing is undoubtedly a complex field, which includes far more depth than this piece can provide. For more information about neutral atom quantum computing, please read this research paper presented by Pasqal's lead researchers and founders.

Benefits of a Neutral Atom Architecture

Compared to other forms of quantum computing, the neutral atom architecture has a number of benefits.

For one, the neutral atoms offer long coherence times, meaning the qubits can maintain their quantum state for a long period of time. In rubidium-based neutral atom solutions, the qubit is often defined as the two hyperfine ground states (F = 1 and F = 2) of the rubidium atom, which creates qubits with coherence on the order of tens of milliseconds. This is important for the development of large-scale quantum computers because the qubits can store quantum information for longer periods of time with fewer chances of environmental variables impacting the state of the qubit.

Depiction of how a neutral atom quantum processor works. Image courtesy of Medium

Additionally, neutral atom solutions are said to be extremely flexible and scalable. This is because many qubits can be manipulated in parallel—another necessary factor to develop large-scale quantum computers. According to Pasqal, neutral atoms pave a clear path forward to build large-scale, thousand-qubit quantum computers.

Pasqal Secures Funding

This week, Pasqal secured over \$100M in a series B funding round.

According to the company, the new funding will be used to fuel the company’s research and development efforts toward the goal of a 1,000-qubit quantum computer. Along with this, the company’s major R&D effort will focus on developing a quantum computer that offers commercial advantages over classical computers by 2024.

The company will also expand its global footprint by opening new offices in the Middle East and Asia, adding 100 new employees, and increasing the production of its quantum systems.