IBM Quantum and UC Berkeley researchers have published a paper in Nature demonstrating the utility of quantum computing. Quantum utility refers to a quantum computer’s ability to perform reliable computations beyond the capabilities of classical computing methods. This marks a significant milestone in the field, as quantum computers were previously small, experimental devices used primarily for studying quantum computing. IBM’s Quantum Theory and Computational Science director, Katie Pizzolato, and Quantum Theory and Capabilities senior manager, Sarah Sheldon, emphasise the potential of quantum computers as tools for scientific exploration.
Quantum Computing: A New Era of Utility
Quantum computers are now capable of solving problems that were previously only accessible to classical approximation methods. This significant development is referred to as quantum utility. Quantum utility is achieved when a quantum computer can perform reliable computations at a scale beyond the capabilities of classical computing methods. This is a significant milestone in the field of quantum computing, as until recently, quantum computers were primarily used for advancing the study of quantum computing itself. Now, they are valuable tools that researchers can use to explore meaningful scientific problems.
Quantum utility is different from quantum advantage. Quantum utility refers to quantum computation that provides reliable, accurate solutions to problems that are beyond the reach of classical computing methods. On the other hand, quantum advantage refers to quantum computation that delivers a significant, practical benefit beyond either brute force or approximate classical computing methods, calculating solutions in a way that is cheaper, faster or more accurate than all known classical alternatives.
Quantum Utility vs Quantum Advantage
Quantum utility and quantum advantage are two distinct concepts in the field of quantum computing. Quantum utility refers to the ability of quantum computers to provide reliable, accurate solutions to problems that are beyond the reach of classical computing methods. This does not mean that quantum methods have achieved a proven speed-up over all known classical methods.
Quantum advantage, on the other hand, refers to quantum computation that delivers a significant, practical benefit beyond either brute force or approximate classical computing methods. This means that quantum computers can calculate solutions in a way that is cheaper, faster or more accurate than all known classical alternatives. Researchers believe that quantum advantage will not occur as a single moment in time, but rather as an incremental journey.
The Importance of Quantum Utility
The era of quantum utility signifies that quantum computers have now reached a level of scale and reliability that allows researchers to use them as a tool for scientific exploration. This could potentially lead to groundbreaking new scientific insights. This is particularly relevant for researchers working on simulations of quantum systems.
When modelling a quantum system of around 20 qubits, brute force classical methods can yield very good results. However, once simulations grow to the 50-qubit range and beyond, classical resources cannot overcome the need for clever, time-consuming, problem-specific approximations. With the growing scale and reliability of quantum hardware, quantum computers can now deliver reliable results for simulation problems at a scale beyond 100 qubits.
The Journey to Quantum Advantage
The journey to quantum advantage is a process that involves running quantum circuits faster on quantum hardware and mapping interesting problems to quantum circuits. These applications can only be solved with quantum circuits and are known to be difficult to simulate using classical techniques.
The journey to quantum advantage will be one in which utility-scale experiments empower researchers to first find applications with practical relevance, and then quantum advantage. To begin this journey, organisations exploring quantum computing must move beyond classical simulations of quantum hardware and small experiments on devices with fewer than 100 qubits.
The Future of Quantum Computing
The future of quantum computing involves more quantum experiments and more benchmarking against ever-improving classical methods. This will require a back-and-forth between quantum and classical methods. The recent utility experiment conducted by IBM and UC Berkeley was quickly followed by numerous papers demonstrating new classical methods designed to match or exceed the IBM result.
In the future, quantum computers will continue to advance, and so will classical approximation methods. The hope is that there will be a back-and-forth between the two sides, which in time the quantum device will end up winning. This will require continuous effort in understanding what the systems we do have available are really capable of, as this is the only path to discovery.
“We’re finally moving past the days when quantum computers were only useful for learning more about quantum computing,” said Katie Pizzolato, IBM’s director of Quantum Theory and Computational Science. “These are scientific tools that are like nothing scientists have ever had access to before. We have an idea of the kinds of problems we want to start exploring with these tools, but there is a lot of exploring to do.”
“This is why we’re so excited to see what will happen once users start exploring more utility-scale problems with these devices,” said Sarah Sheldon, IBM’s senior manager of Quantum Theory and Capabilities. “We haven’t yet found a practical problem for which quantum computers offer a meaningful speedup over classical methods, but the more users experiment with these systems, the more optimistic we are that it will happen.”
“Getting reliable results at this scale is something many people doubted would ever be possible on current devices,“ said Kristan Temme, a principal research staff member in Quantum Theory and Capabilities at IBM. “Quantum computers will continue advancing, and so will classical approximation methods. Our hope is that we will start to see a back-and-forth between the two sides, which in time the quantum device will end up winning.”
“Utility is basically the first key step towards a demonstration of advantage,” said Abhinav Kandala, IBM’s manager of Quantum Capabilities and Demonstrations. “You want to show that quantum machines can provide reliable results for problems at a scale beyond what we can do with brute force classical simulation. Once you show that, the next step is to find hard problems that are valuable to researchers and solvable with quantum computation. Being able to do both gets you quantum advantage.”
“We’re enabling enterprise and research organizations to use the capabilities that power utility-scale demonstrations so they can explore use cases at a non-trivial scale,” said Tushar Mittal, IBM’s head of product for Quantum Services. “We’re entering a time where, now that we have the capabilities to take on large-scale problems, we need help from our partners to figure out which of their use cases will actually benefit. Ultimately, it will be our clients and partners who claim the first instances quantum advantage, not IBM.”
“Quantum computing is finally proving itself as a computational tool for scientific exploration,” Kandala said. “I’m excited to see what we can do with the next set of improvements to quantum hardware, and with input from the community on where to look for challenging circuits.”
Executive Summary
Quantum computers are now capable of solving problems beyond the reach of traditional computing methods, marking a significant milestone in the field. This development, termed ‘quantum utility’, allows researchers to use quantum computers to explore complex scientific problems, potentially leading to groundbreaking new insights.
- Quantum computers are now capable of solving problems beyond the reach of classical computing methods, marking a significant milestone in the field. This is referred to as ‘quantum utility’.
- Researchers at IBM Quantum and UC Berkeley have published a paper on this topic in the scientific journal Nature.
- Quantum utility is different from ‘quantum advantage’, which refers to quantum computation delivering significant, practical benefits beyond classical computing methods.
- Quantum computers were previously small, experimental devices used mainly for studying quantum computing itself. Now, they are valuable tools for exploring scientific problems.
- IBM’s Quantum Theory and Computational Science director, Katie Pizzolato, and senior manager of Quantum Theory and Capabilities, Sarah Sheldon, have expressed optimism about the potential of quantum computers.
- Quantum computers can now deliver reliable results for large-scale problems, which can help verify classical approximations.
- IBM’s manager of Quantum Capabilities and Demonstrations, Abhinav Kandala, sees quantum utility as the first step towards demonstrating quantum advantage.
- IBM’s head of product for Quantum Services, Tushar Mittal, believes that research partnerships and the search for useful quantum computing applications will reveal useful information about the near-term hardware and software capabilities needed to achieve quantum advantage.
- Quantum computers are expected to continue advancing, with a back-and-forth between quantum and classical methods.