Understanding Quantum Parallelism and Interference in Quantum Computing

think about this next time you bet big on moving to Quantum Proof cryptography I wonder if this reflects the state across all factions in research or if some covert project where bespoke hardware is purposefully made would make a dent or maybe even break weaker keys we now think unbreakable. I've come to think we shouldn't trust too much in what is now considered Quantum Proof until actual hardware is built running at intended production level reliability and performance. #tech #crypto

Indeed, we need more #quantumalgorithms, we need more quantum algorithms that have the potential to show practical utility and we need to achieve a better understanding - say, on end-to-end complexity or the range of applicability - of those already known.

Beyond Shor's Algorithm: Why His Own Field Has Passed Him By Professor Shor, Your contribution to the field remains the paradigmatic demonstration of what a quantum computer could achieve. But precisely because of the weight your voice carries, I feel compelled to correct several points in your framing. You presented “quantum supremacy” as if it were reducible to the act of factoring large integers on a fault-tolerant machine, and further suggested that this goal remains “several decades away.” With due respect, this is a mischaracterization. Supremacy is not, and has never been, synonymous with cryptographic collapse. It is a complexity-theoretic notion: the existence of any problem in BQP demonstrably intractable for classical machines. By that definition, supremacy demonstrations already exist—random circuit sampling (Google’s Sycamore), boson sampling (Xanadu’s Borealis), Gaussian boson sampling with threshold detectors. These are not speculative curiosities; they are experimentally verified instantiations of separations between quantum and classical resources, unless one chooses to redefine supremacy post hoc as “breaking RSA or nothing.” Your suggestion that improved classical algorithms may refute these demonstrations is a valid caveat but ultimately bounded. Complexity theory (Aaronson–Arkhipov; Bremner–Montanaro–Shepherd) shows that efficient classical simulation of such distributions would collapse the polynomial hierarchy—an outcome more radical than accepting the reality of quantum advantage. Temporary algorithmic workarounds (tensor networks, Clifford+T stabilizer simulators) narrow but do not erase the separation. Moreover, the prediction that factoring is “decades away” rests on a linear extrapolation of today’s error rates. This ignores the non-linear trajectory of progress: bosonic encodings (GKP states), LDPC codes with constant overhead, modular ion-trap arrays, and photonic cluster states. Logical qubits with demonstrated break-even error suppression already exist. To dismiss these as incremental curiosities is to repeat, in 1946, the claim that stored-program digital machines were “obviously” incapable of scaling. What matters here is conceptual clarity. Supremacy is not utility. Factoring will indeed be the cryptographically dramatic instantiation, but it is not the definitional gatekeeper. To equate supremacy with factoring is to erase the very progress that your own algorithm inspired. Supremacy has already been achieved in restricted but complexity-theoretically rigorous models. To suggest otherwise risks turning a scientific milestone into a rhetorical mirage. Few individuals have shaped quantum computation as deeply as you have. For that reason, when you speak, the community listens—and sometimes uncritically. With admiration for your foundational work, but with equal commitment to correcting what must not remain unchallenged, Marcos Eduardo Elias Founder, Holosystems Quantum Algorithms / EquiVerse AI

Dear quantum experts and enthusiasts, you want to tell apart reality, realistic forecast and hype? You want to know which players, use cases,... are winning? Then take three steps: 1. Follow Jens Eisert and his advice: "quantum computing is also interesting if you only say things that are true" 2. As nothing in the world comes for free: If you want to leverage a machine for your needs, know your requirements and specs (hardwarefootprint aka "end-to-end" complexities for your algorithm and use case) 3. If step 2 is unclear ask your trusted advisor and providers for help Because if a foreign prince is offering you a magic machine that prints money at no effort and for free, the output of your efforts will very likely be snake oil. #quanta4breakfast

Logical consistency between disagreeing experts can be used to keep us safer when we use their noisy decisions. My latest on this overlooked tool to tame AIs -- submitted to IEEE SaTML 2026 in Berlin. arxiv.org/abs/2510.00821

I completely agree with the conclusion: "What's needed are new algorithms". This is by no means a trivial matter. Factorization is often seen as the poster child of quantum computing, thanks to Shor's algorithm, but there is much more potential to explore. This is why I encourage students to invest more in mathematical skills. I believe there are great benefits to quantum computing that can be unlocked by applying the appropriate algorithms that leverage quantum phenomena like superposition and entanglement. This is actually the same principle behind Shor's own factorization algorithm: transform an existing problem into a different one (period finding) and design a quantum algorithm that "excels" at it .

Quantum today= bigger chips or smarter algorithms. what's missing= the glue. A unifying framework that orchestrates hybrid computation, decides when to use what, audits results, and keeps it all coherent across noisy subsystems. like the internet before TCP/IP, the breakthrough isn't speed or smarter algorithms alone, its the connection. -Ps, We will also need hardware capable of computing based on non abelian algebra if we want fault tolerant, truly scalable quantum computation. and not the one that uses superconductors since they need cryogenic systems.

Recently published in Quantum: Towards violations of Local Friendliness with quantum computers by William J. Zeng, Farrokh Labib, and Vincent Russo https://lnkd.in/efMbaMgd

Our Local Friendliness violations paper has now been published in the journal Quantum! Quantum tech has important commercial as well as basic science applications. We show how you can use quantum computers to run increasingly important quantum foundations experiments. We use quantum computers to try and shed light on what observers are, proposing further experimental tests to help resolve the measurement problem in quantum mechanics. Work from Unitary Foundation joint with Farrokh Labib and Vincent Russo. w/ thanks to O'Shaughnessy Ventures and James O'Shaughnessy for supporting this work and to IBM Quantum, IQM Quantum Computers, and Quantinuum for their devices.

Quantum computing delivers measurable competitive advantages when deployed strategically. Dr. Bhavika B. and Dr. Markus B. represented Unisys at IEEE Quantum Week 2025, presenting two breakthrough studies on aircraft loading optimization and enhanced financial risk prediction. Learn more: http://spr.ly/6043Ap7iB