QuEra Computing Inc.’s Post

📌 Article presented by BBVA and CSIC under the title "Multiobjective variational quantum optimization for constrained problems: an application to cash handling": https://lnkd.in/dijrFhfc Combinatorial optimization problems are ubiquitous in industry. In addition to finding a solution with minimum cost, problems of high relevance involve a number of constraints that the solution must satisfy. Variational quantum algorithms (VQAs) have emerged as promising candidates for solving these problems in the noisy intermediate-scale quantum stage. However, the constraints are often complex enough to make their efficient mapping to quantum hardware difficult or even infeasible. An alternative standard approach is to transform the optimization problem to include these constraints as penalty terms, but this method involves additional hyperparameters and does not ensure that the constraints are satisfied due to the existence of local minima. In this paper, we introduce a new method for solving combinatorial optimization problems with challenging constraints using VQAs. We propose the multi-objective variational constrained optimizer (MOVCO) to classically update the variational parameters by a multiobjective optimization performed by a genetic algorithm. This optimization allows the algorithm to progressively sample only states within the in-constraints space, while optimizing the energy of these states. We test our proposal on a real-world problem with great relevance in finance: the cash handling problem. We introduce a novel mathematical formulation for this problem, and compare the performance of MOVCO versus a penalty based optimization. Our empirical results show a significant improvement in terms of the cost of the achieved solutions, but especially in the avoidance of local minima that do not satisfy any of the mandatory constraints. #ProyectoCUCO #BPQCO #QuantumComputing #QuantumCircuitOptimization #QuantumSimulation

As members of the quantum consortium QED-C, we are proud to collaborate with the National Institute of Standards and Technology (NIST) and colleagues on exploring quantum benchmarking. As part of this effort, we recently co-authored a new paper on application-oriented performance benchmarks. Benchmarking is a critical element in the fast-changing landscape of quantum computing – quality benchmarking allows potential users and investors to compare different quantum computing architectures, algorithms, and approaches intelligently and efficiently. In particular, users need to gauge the performance of real-world applications.     Our recent paper extends a suite of Application-Oriented Benchmarks for quantum computing, covering a range of sizes and inputs, capturing key performance metrics related to the quality of results, total time of execution, and resources consumed. This paper includes the results of running these extended benchmarks with a variety of architectures and software tools, giving a clear measure of the field at present.    Read more here: https://lnkd.in/dp_RfUSh

Preprint 3/3 for this year is done! Check out it here: https://lnkd.in/eidZehF2 It was a pleasure to work with the fantastic Grzegorz Rajchel-Mieldzioć on this work for over a year. I look forward to our continued collaboration on further cutting edge, exciting topics in quantum information and dynamics. Special thanks also go to Marcin Płodzień, PhD, José Ramón Martínez Saavedra for their feedback on the manuscript! In other news, our first work of the year (https://lnkd.in/eURzRvkE) has now been accepted into PRA. Special thanks to David Jansen for getting this one over the line. Abstract: The ability to characterise and discern quantum channels is a crucial aspect of noisy quantum technologies. In this work, we explore the problem of distinguishing quantum channels when limited to sub-exponential resources, framed as von Neumann (projective) measurements. We completely characterise equivalence classes of quantum channels with different Kraus ranks that have the same marginal distributions under compatible projective measurements. In doing so, we explicitly identify gauge freedoms which can be varied without changing those compatible marginal outcome distributions, opening new avenues for quantum channel simulation, variational quantum channels, as well as novel adversarial strategies in noisy quantum device certification. Specifically, we show how a Sinkhorn-like algorithm enables us to find the minimum admissible Kraus rank that generates the correct outcome marginals. For a generic d-dimensional quantum system, this lowers the Kraus rank from d**2 to the theoretical minimum of d. For up to d=20, we numerically demonstrate our findings, for which the code is available and open source. Finally, we provide an analytic algorithm for the special case of spoofing Pauli channels.

This is a great, insightful work from Tim Heightman and Grzegorz Rajchel-Mieldzioć! In layperson's terms (and, hopefully, I'm not oversimplifying), they show how most complex quantum channels can be described using other, more simple ones without losing any information about their measurable effects. These results improve the simulation of quantum channels by simplifying their description, making it easier to analyze, simulate, and certify quantum devices. Moreover, these results can also be applied to developing adversarial strategies, which will become increasingly important as these devices become more involved in practical applications. Congratulations to the authors!

It is great to see advancements in all the use cases for quantum algorithms.

Amazing new #quantum research result from Google ❤️: a new quantum algorithm that gives an exponential speedup over known classical methods for solving certain #optimization problems: „decoded quantum interferometry” (DQI) 👏😎 Optimization algorithms are a cornerstone of many applications, and we always assumed that quantum computers can achieve max quadratic speedups over best possible classsical algorithm. This new result now is amazing! https://lnkd.in/eg2xE2Zr

A perfect example of a joint work between tool developers and hardware experts: Our comprehensive overview paper of software compilation for Neutral Atom #QuantumComputing just got published in Quantum Science and Technology. Neutral Atom #QuantumComputing seems to be everyone’s darling these days. And with good reason as it offers numerous computational capabilities! But those are only as good as the corresponding compilers that make use of it. Hence, to fully utilize the potential of this technology, tool developers and hardware experts need to work hand-in-hand. Our paper aims to provide a basis for that: It reviews the physical background of Neutral Atoms and translates the corresponding principles into a form with which also tool developers can do something with. A special "feature": All take home-messages for tool developers are summarized in form of optimization constraints and figures of merit in self-contained boxes. For everyone interested in developing tools for this technology, definitely worth a look: 👉 https://lnkd.in/e4fTP4px This work is one of the results from several Technical Exchange Meetings we conducted within the Munich Quantum Valley in an effort to close the gap between tool developers and hardware experts (involving Technische Universität München, RWTH Aachen University, Forschungszentrum Jülich, Ludwig-Maximilians-Universität München, Max Planck Institute, Munich Center for Quantum Science and Technology, and the Software Competence Center Hagenberg). Huge thanks to Ludwig Schmid, David F. Locher, Manuel Rispler Sebastian Blatt, Johannes Zeiher, and Markus Müller for this great collaboration and Munich Quantum Valley as well as the European Research Council (ERC) for the support.

While analog neutral-atom machines are highly performant, it is widely understood that the limitations of problems they can address represent an issue to the technology adoption. In this work, our algorithms team introduces a “non-native hybrid algorithms” paradigm which utilizes the quantum system to provide hints that enhance the performance of classical routine for problems outside the architecture’s native space (i.e. maximum independent sets on unit-disk graphs). Data from Aquila, our 256 quantum computer, demonstrate solutions for Max k-cut problems and more, indeed showcasing the power of this methodology. https://hubs.ly/Q02t8HBT0

Following up, a paper led by Madelyn Cain from Harvard, with participation of QuEra researchers. If you followed up the big news of last December on experiments demonstrating complex circuits with 48 logical neutral atom qubits, you may have read about the advances in error-correction decoding protocols that enabled the work. This paper describes exactly those advances in detail, showcasing how joint decoding of qubits during transversal entangling gates can reduce error propagation and substantially reduce the overheads on rounds of syndrome extraction per gate. https://hubs.ly/Q02t8P5H0

Looks like we're quickly closing the gap on this optimization problem - "Extrapolating their numerical simulation results, the team estimated that there may be a quantum speedup for this problem with a 2-qubit gate infidelity around 10-5 and roughly 2000 qubits. Our H1 system already boasts a world-class 2-qubit gate infidelity of 8.8 × 10-4."