A selection of the most important recent news, articles, and papers about Quantum.
General News, Articles, and Analyses
Introducing Qiskit Code Assistant | IBM Quantum Computing Blog
https://www.ibm.com/quantum/blog/qiskit-code-assistant
Authors: Daniella Garcia Almeida; Juan Cruz-Benito; and Robert Davis
(Wednesday, October 9, 2024) “To bring useful quantum computing the world, it isn’t enough to build the world’s most performant quantum software, or its largest fleet of utility-scale quantum processors. We also have to empower users to make efficient and effective use of the tools we’ve created. With the release of Qiskit Code Assistant, now available as a private preview via the IBM Quantum Premium Plan, we’re doing exactly that.”
Quantum computing group Q-CTRL secures $87m top-up for a record $167m Series B capital raise
(Wednesday, October 9, 2024) “Sydney-based quantum computing group Q-CTRL has expanded its Series B Funding round to a record US$113 million ($167.5 million) after raising an additional US$59 million ($87.5 million) led by British technology advisory and investor GP Bullhound.”
‘Quantum computing is taking longer than going to the moon’: Ex-IBM exec Robert Sutor on Europe’s quantum computing startups | Sifted
https://sifted.eu/articles/robert-sutor-quantum-ibm-nu-interview
Author: Daphné Leprince-Ringuet
(Thursday, October 10, 2024) “After nearly 40 years at IBM, Sutor is now taking a keen interest in startups — and he says they are the future of quantum computing.”
Technical Papers, Articles, and Preprints
[2410.06966] Variational approach to photonic quantum circuits via the parameter shift rule
https://arxiv.org/abs/2410.06966
Authors: Hoch, Francesco; Rodari, Giovanni; Giordani, Taira; Perret, Paul; Spagnolo, Nicolò; Carvacho, Gonzalo; Pentangelo, Ciro; Piacentini, Simone; Crespi, Andrea; Ceccarelli, Francesco; Osellame, Roberto; and Sciarrino, Fabio
(Wednesday, October 9, 2024) “In the current era of noisy intermediate-scale quantum computers, variational quantum algorithms represent one of the most viable approaches for their application to solve tasks of interest. These algorithms train a parameterized quantum circuit to execute a specific task encoded in a cost function that needs to be minimized using a classical optimizer. In this context, photonic platforms based on reconfigurable integrated optics appear as one of the prominent platforms for the implementation of variational algorithms. In the circuital model of quantum computation based on qubits, to train variational circuits, the parameter shift rule came into being, which allows for the exact calculation of the derivatives of many functions at the output of a quantum circuit, opening up the possibility of using classical optimisation algorithms based on gradient descent. In this paper, we derive a formulation of the parameter shift rule for reconfigurable optical linear circuits based on the Boson Sampling paradigm. This allows us to naturally embed the common types of experimental noise, such as partial distinguishability, and mixedness of the states, thus obtaining a resilient approach. We also present similar rules for the computations of integrals over the variational parameters. Finally, we employ the developed approach to experimentally test variational algorithms with single-photon states processed in a reconfigurable 6-mode universal integrated interferometer. Specifically, we apply the photonic parameter shift rules to the variational implementation, on a photonic platform, of both an eigensolver and a Universal-Not gate.”
[2410.07065] Enhanced Fault-tolerance in Photonic Quantum Computing: Floquet Code Outperforms Surface Code in Tailored Architecture
https://arxiv.org/abs/2410.07065
Authors: Hilaire, Paul; Dessertaine, Théo; Bourdoncle, Boris; Denys, Aurélie; de Gliniasty, Grégoire; Valentí-Rojas, Gerard; and Mansfield, Shane
(Wednesday, October 9, 2024) “Fault-tolerant quantum computing is crucial for realizing large-scale quantum computation, and the interplay between hardware architecture and quantum error-correcting codes is a key consideration. We present a comparative study of two quantum error-correcting codes – the surface code and the honeycomb Floquet code – implemented on variants of the spin-optical quantum computing architecture, enabling a direct comparison of the codes using consistent noise models. Our results demonstrate that the honeycomb Floquet code significantly outperforms the surface code in this setting. Notably, we achieve a photon loss threshold of 6.4% for the honeycomb Floquet code implementation – to our knowledge the highest reported for photonic platforms to date without large-scale multiplexing. This finding is particularly significant given that photon loss is the primary source of errors in photon-mediated quantum computing.”
[2410.08010] Study of Attacks on the HHL Quantum Algorithm
https://arxiv.org/abs/2410.08010
Authors: Tan, Yizhuo; Kukina, Hrvoje; and Szefer, Jakub
(Thursday, October 10, 2024) “As the quantum research community continues to grow and new algorithms are designed, developed, and implemented, it is crucial to start thinking about security aspects and potential threats that could result in misuse of the algorithms, or jeopardize the information processed with these quantum algorithms. This work focuses on exploration of two types of potential attacks that could be deployed on a cloud-based quantum computer by an attacker circuit trying to interfere with victim circuit. The two attacks, called Improper Initialization Attack (IIA) and Higher Energy Attack (HEA), are for the first time applied to a well-known and widely used quantum algorithm: HHL. The HHL algorithm is used in the field of machine learning and big data for solving systems of linear equations. This work evaluates the effect of the attacks on different qubits within the HHL algorithm: ancilla qubit, clock qubit, and b qubit. This work demonstrates that the two attacks are able to cause incorrect results, even when only one of the qubits in the victim algorithm is attacked. Having discovered the vulnerabilities, the work motivates the need for future work to develop defense strategies for each of these attack scenarios.”
