Recent additions to Quantum Computing (QC) processors are without end. During the last three months, Google, Microsoft, and the University of Science and Technology of China (USTC) unveiled several new QC chips with different approaches racing to achieve quantum utility.

Now, Amazon Web Services (AWS) joins the latest race and unveils its recent innovation: the Ocelot quantum computing chip. This chip represents a significant stride in the quest to build fault-tolerant quantum computers capable of tackling complex problems currently beyond the reach of conventional computers. 

The Ocelot chip, developed at the AWS Center for Quantum Computing at the California Institute of Technology, takes a novel approach to quantum error correction.

AWS Quantum Computing Center

The seeds for this breakthrough were sown in 2019 when Amazon launched the AWS Center for Quantum Computing, followed by the opening of its new facility at Caltech in 2021. The center’s ambitious goal was to construct a “fault-tolerant” quantum computer capable of performing accurate computations at a scale. 

The initiative brought together quantum computing experts from Amazon, Caltech, and other leading academic institutions, fostering a collaborative environment to accelerate the development of quantum technologies and applications.

Building a quantum computer is challenging. Qubits can exist in a superposition state, representing both 0 and 1 simultaneously, allowing quantum computers to perform specific calculations exponentially faster than classical computers.

There is no agreement on the most effective method for creating qubits, and it’s uncertain whether future quantum computers will utilize various technologies tailored for specific tasks rather than a single approach. Qubits are incredibly sensitive to environmental noise, such as vibrations or heat, which can cause them to lose information and become error-prone.

EC challenge of Quantum Computing

One of the biggest hurdles in quantum computing is maintaining the stability and fidelity of qubits while scaling their number. Quantum error correction is crucial for building reliable quantum computers. 

The challenge is to encode quantum information across multiple qubits to shield it from environmental noise and enable the detection and correction of errors. However, current approaches to quantum error correction require a massive number of qubits, making them prohibitively expensive.

Ocelot builds on error correction

AWS researchers adopted a new approach with the Ocelot chip to overcome these challenges, building error correction into the architecture from the ground up. “We didn’t take an existing architecture and then try to incorporate error correction afterward,” said Oskar Painter, AWS director of Quantum Hardware. “[and] selected our qubit and architecture with quantum error correction as the top requirement. We believe that if we’re going to make practical quantum computers, quantum error correction needs to come first.”

The Ocelot chip utilizes ‘cat qubits,’ named after Schrödinger’s cat thought experiment. These qubits intrinsically suppress certain forms of errors, reducing the resources required for quantum error correction. By combining cat qubit technology with additional quantum error correction components on a microchip, AWS aims to reduce the costs of implementing quantum error correction by up to 90% compared to current approaches.

Painter estimates that scaling Ocelot to a “fully-fledged quantum computer capable of transformative societal impact would require as little as one-tenth of the resources associated with standard quantum error correcting approaches.”

Reducing resources means that quantum computers can be smaller, more reliable, and cheaper, accelerating the path to real-world applications.

Inside the Ocelot chip

The Ocelot chip is a prototype consisting of two integrated silicon microchips, each with an area of roughly 1 cm². The chips bond together in an electrically connected stack. The surface of each silicon microchip contains thin layers of superconducting materials that form the quantum circuit elements. 

The Ocelot chip comprises 14 core components: five data qubits (the cat qubits), five ‘buffer circuits’ for stabilizing the cat qubits, and four additional qubits for detecting errors in the cat qubits. The cat qubits store the quantum states used for computation, relying on oscillators made from a thin film of superconducting material called Tantalum.

Competitive race in the commercial sector

The announcement of the Ocelot chip comes amid a flurry of activity in the quantum computing arena. Google recently unveiled its Willow chip, boasting 105 qubits and demonstrating breakthroughs in quantum error correction. Willow can perform computations in minutes that would take supercomputers billions of years, showcasing the exponential computational power of quantum computers.

Microsoft has also made waves with its Majorana 1 chip, which utilizes a topological qubit architecture designed to be more resilient to environmental disturbances than conventional qubits. Microsoft’s approach focuses on stability and scalability, aiming to overcome key challenges in the field. The company has placed eight topological qubits on a chip designed to scale to one million.

These advancements highlight the intense competition among major players in the quantum computing race, each pursuing different approaches to achieve quantum supremacy. While Google and others have focused on scaling the number of qubits and demonstrating quantum computational advantage, Amazon and Microsoft are prioritizing error correction and stability.

Gateway to Quantum Computing with AWS Braket

For those eager to explore quantum computing’s possibilities, Amazon Braket provides a managed service that allows scientists, developers, and students to work with various quantum computing hardware, high-performance simulators, and software tools. 

Amazon Braket offers access to quantum hardware based on superconducting qubits from IQM and Rigetti, ion-trap quantum computers from IonQ, and Rydberg atom-based quantum computers from QuEra Computing.

Quantum computing has great potential for addressing complex problems, although it continues to encounter substantial challenges. Technology companies are increasingly dedicated to advancing the development of functional machines, moving from a phase of scientific exploration to actively addressing engineering obstacles.

As the field of quantum computing continues to evolve, collaboration between researchers, engineers, and policymakers will be essential. The journey towards quantum supremacy is a marathon, not a sprint.

From EETimes