Commentary and a selection of the most important recent news, articles, and papers about Quantum.
Today’s Brief Commentary
Ahead of my talk at Q2B Silicon Valley on December 12 and an Analyst Insight article for The Futurum Group, I’ve been looking at companies around the world who claim to be creating quantum processing units (QPUs). Here are some of my impressions that I’ve gleaned from personal knowledge, company websites, listings of quantum computing companies, and general research:
- It’s difficult to tell if a company is really (still) actively in business. Clues that it may not include a missing website, a one-page website, no listing of team members, and no company physical address.
- A minority of companies mention how many physical qubits they have and whether they have demonstrated entanglement.
- Companies often spend so much time repeating why we think quantum computing will be valuable. I understand you want to be self-contained, but could you try to be slightly original in your descriptions? After a while, many websites look alike with very little differentiation. Help is available for messaging. I compliment many companies on their graphics, especially animations. Just don’t make me wait too long or have to scroll to find out what you do.
- You are not all “world leaders in quantum computing.” Perhaps you are the leader in your region or country.
- You do not all do “full-stack quantum computing.” “Full-stack” does not equal “whatever we happen to do.” I repeat this a lot, but it is a hollow claim for many organizations, and people know it. Like your claim of intergalactic quantum predominance, it can leave a bad first impression that makes people question any later claims.
- Tell us why you have a chance to do something great. Expand upon your unique expertise in science, engineering, and business. Make me understand why I should pay attention to you. Please.
P.S. Some of you need to be much clearer about whether you are using silicon spin qubits or superconducting qubits such as transmons.
Semiconductor Chipsets and Infrastructure
First ever CMOS transistor fully optimized for cryogenic conditions released by SemiQon
(Tuesday, November 26, 2024) “This new innovation dramatically increases performance of electronics through elimination of heat dissipation and enables scalability of quantum computers.”
Government Policy and Legislation
Bipartisan quantum funding bill advances from committee | Washington Technology
Author: Alexandra Kelley
Commentary:
It’s not at all clear that this will get passed and signed into law before the US change of government in January.(Monday, November 25, 2024) “The Department of Energy Quantum Leadership Act of 2024 — a bipartisan bill authored by Sens. Dick Durbin, D-Ill., and Steve Daines, R-Mont. — contains multiple provisions related to quantum technology and sciences research, namely funding federal efforts in quantum networking research and development, establishing domestic foundry programs and conducting industry outreach efforts.”
Quantum Computing
Qubit that makes most errors obvious now available to customers | Ars Technica
https://arstechnica.com/science/2024/11/first-commercial-dual-rail-qubit-hardware-announced/
Author: John Timmer
Commentary:
Also see the two technical research dual-rail papers below.(Wednesday, November 20, 2024) “The technology is called a dual-rail qubit, and it is intended to make the most common form of error trivially easy to detect in hardware, thus making error correction far more efficient. And, while tech giant Amazon has been experimenting with them, a startup called Quantum Circuits is the first to give the public access to dual-rail qubits via a cloud service.”
IBM Quantum 2024 State of the Union: From utility to algorithm discovery | YouTube
https://youtu.be/4MpLnAo2974?si=za3JjKAxAN4S2wPz
Author: Jay Gambetta
(Tuesday, November 26, 2024) “Last year, IBM Quantum announced that the field had entered the era of quantum utility. Now, it’s time to use utility-scale quantum computers for algorithm discovery. This talk covers the remarkable performance breakthroughs and software and hardware innovations that will allow users to explore uncharted computational territory with quantum computers, plus progress as we push forward along our development and innovation roadmaps.”
IQM to deploy quantum computer in Taiwan | DCD
https://www.datacenterdynamics.com/en/news/iqm-to-deploy-quantum-computer-in-taiwan/
Author: Dan Swinhoe
Commentary:
Five qubits are only good for research, experimentation, and education.(Friday, November 29, 2024) “European quantum computing firm IQM is to deploy a system in Taiwan. The company saw the Taiwan Semiconductor Research Institute (TSRI), under the National Applied Research Laboratories, announce the acquisition of a five-qubit Spark quantum computer.”
Quantum Computing – Technical
Dual-rail encoding with superconducting cavities | Processings of the National Academy of Sciences
https://www.pnas.org/doi/10.1073/pnas.2221736120
Authors: Teoh, James D.; Winkel, Patrick; Babla, Harshvardhan K.; Chapman, Benjamin J.; Claes, Jahan; de Graaf, Stijn J.; Garmon, John W. O.; Kalfus, William D.; Lu, Yao; ; …; and Schoelkopf, Robert J.
(Friday, October 6, 2023) “Here, we propose an architecture for quantum computing that applies the dual-rail encoding from quantum optics to a superconducting quantum circuit platform. In doing so, we not only benefit from the error detection properties of this encoding but also exploit the strong nonlinearities available in superconducting circuits, which enable gate-based quantum computation. While any useful quantum computer is expected to need quantum error correction, direct error detection allows us to know exactly where and when a qubit has an error, making error correction much easier. By designing the dual-rail qubits such that most of their errors can be detected, we believe that practical quantum error correction can already be achieved with the coherence times of today’s superconducting circuits.”
A superconducting dual-rail cavity qubit with erasure-detected logical measurements | Nature Physics
https://www.nature.com/articles/s41567-024-02539-4
Authors: Chou, Kevin S.; Shemma, Tali; McCarrick, Heather; Chien, Tzu-Chiao; Teoh, James D.; Winkel, Patrick; Anderson, Amos; Chen, Jonathan; Curtis, Jacob C.; ; …; and Schoelkopf, Robert J.
(Tuesday, July 2, 2024) “Dual-rail encodings of quantum information can be used to detect loss errors, allowing these errors to be treated as erasures. The measurement of dual-rail states with error detection has now been demonstrated in superconducting cavities.”
[2411.03683] Polylog-time- and constant-space-overhead fault-tolerant quantum computation with quantum low-density parity-check codes
https://arxiv.org/abs/2411.03683
Authors: Tamiya, Shiro; Koashi, Masato; and Yamasaki, Hayata
(Wednesday, November 6, 2024) “A major challenge in fault-tolerant quantum computation (FTQC) is to reduce both space overhead – the large number of physical qubits per logical qubit – and time overhead – the long physical gate sequences per logical gate. We prove that a protocol using non-vanishing-rate quantum low-density parity-check (LDPC) codes, combined with concatenated Steane codes, achieves constant space overhead and polylogarithmic time overhead, even when accounting for non-zero classical computation time. This protocol offers an improvement over existing constant-space-overhead protocols, which have polynomial time overhead using quantum LDPC codes and quasi-polylogarithmic time overhead using concatenated quantum Hamming codes. To ensure the completeness of this proof, we develop a technique called partial circuit reduction, which enables error analysis for the entire fault-tolerant circuit by examining smaller parts composed of a few gadgets. With this technique, we resolve a previously unaddressed logical gap in the existing arguments and complete the proof of the threshold theorem for the constant-space-overhead protocol with quantum LDPC codes. Our work highlights that the quantum-LDPC-code approach can realize FTQC with a negligibly small slowdown and a bounded overhead of physical qubits, similar to the code-concatenation approach, underscoring the importance of a comprehensive comparison of the future realizability of these two approaches.”
Sovereign Initiatives
Quantum Computing in India: Key Advancements in 2024 | The Quantum Insider
https://thequantuminsider.com/2024/11/27/quantum-computing-advancements-in-india/
Author: Cierra Choucair
Commentary:
Great survey article by Cierra Choucair.(Wednesday, November 27, 2024) “India is actively building a quantum ecosystem powered by government support, academic research, and private-sector collaboration.”
