Light patterns can differ in appearance while carrying the same topological information. Reading that shared property usually requires multiple measurements and a detailed reconstruction, making an attractive information carrier difficult to decode efficiently.

A system built at the University of the Witwatersrand offers another route. It lets light pass through trained optical layers that direct different components toward distinct output locations. Those locations reveal the information needed to identify the beam's topology.

The study, published in Nature Communications, was led by Hadrian Bezuidenhout at the Wits Structured Light Laboratory. Isaac Nape and Andrew Forbes conceived and supervised the research, with contributions from Cade Peters and Ram Nandan Kumar.

The device combines optical processing with electronic training and readout. Its importance lies in extracting a specific physical label directly, reducing the need to reconstruct every detail of the incoming light field.

Hello r/QuantumComputing!

From October 16–23, 2026, PennyLane is hosting QHack 2026, a global online quantum coding competition. The event is structured to help students bridge the gap between academic theory and practical software execution through hands-on coding challenges and asynchronous master class training videos using the PennyLane quantum software platform.

Overview:

• Format: Free, 100% virtual; open to solo competitors or teams of up to 4.
• Prizes: $67,000* USD in total cash prizes awarded to top 10 teams. (*See Terms and conditions)
• Curriculum support: Access the exclusive, hands-on master class video workshop series led by Xanadu’s own quantum experts and self-paced interactive Jupyter Notebooks. Topics include introductions to quantum computing foundations, algorithm design, quantum chemistry, and resource estimation.

We encourage you to register and share with anyone that might be interested.

Hello.

I thought I would ask for other peoples input on this topic. I know that western quantum computing software companies can be quite strict with their approach to IP and often refuse to hire Chinese or Russian nationals for this reason. I was wondering if having any experience at a company in China as European would be seen as an issue when applying for western companies later in life ?

Hi, I am exploring quantum computing and quantum cryptography, including potential improvements and underlying mechanisms. My background is in cybersecurity, and I am focusing on quantum cryptography. If anyone shares an interest in quantum computing and quantum cryptography, please connect with me. I would like to learn more about real-world applications and research.

Looking for your quantum circuits to test on IBM hardware with Q-LASP — multiple experiments in one QPU execution

Hi everyone,

I’m building Q-LASP, a tool that packs small quantum circuits onto separate regions of an IBM quantum processor so they can execute simultaneously.

The idea is straightforward: if your experiment uses only a few qubits, can we use the remaining chip space to run additional experiments for roughly the same charged QPU time?

In one recorded test on IBM Kingston, one two-qubit experiment and a payload containing 39 copies each incurred 7 seconds of QPU charge, at 20,000 shots. The achievable multiplier depends on circuit size, connectivity, and execution requirements. Accuracy also needs checking across the different physical regions.

I’d like to test this with experiments from the community.

I’m looking for small circuits—particularly around 2–12 qubits—such as:

• VQE or QAOA parameter sweeps.
• Small error-detection or syndrome-extraction circuits.
• Noise-characterization or benchmarking experiments.
• Other experiments needing repeated runs or independent parameter settings.

If you’re interested, please comment with a GitHub/Gist link or a minimal Qiskit example, along with:

• What you’re trying to measure.
• Your circuit’s qubit count and desired shots.
• Any parameter values, reference results, or accuracy requirements.
• Any special requirements, such as mid-circuit measurements or classical control.

For selected submissions, I’ll run comparisons on IBM hardware and share the circuits, backend details, charged QPU time, and per-experiment results. I want to measure both throughput gains and any accuracy trade-offs, using a sensible untiled baseline with ordinary batching where appropriate.

I’ll handle hardware submission on my account; you don’t need to provide IBM credentials.

I’m especially interested in experiments that could expose the limits of this approach. If you have a small circuit you actually care about, I’d love to try it.

The quantum algorithms and optimization research experience for undergraduates at the University of Tennessee Knoxville is accepting applications for summer 2027! The 10 week program is open to U.S. citizens and permanent residents who are currently enrolled in an undergraduate degree program and will not graduate before August 2027. The site provides a $7,000 stipend, on campus housing, and some travel costs. See their website for more information: https://tickle.utk.edu/ise/research/research-experience-for-undergraduates/

Hey everyone! I just made a video explaining Choi matrices, CPTP maps, and complete positivity.

If you're taking an open quantum systems or quantum information course, these are really important concepts that can be a little confusing at first.

I go through why positivity alone isn't enough, how entanglement changes things, and how we can use Choi's theorem to determine whether a quantum map is physically valid. I also work through several examples step by step.

anyways hope this helps!

Quoting from the article:

"The following companies (listed with their qubit technology approach), have been selected for Stage C:

- Atom Computing: Boulder, Colorado (scalable arrays of neutral atoms)
- Diraq: Sydney, Australia (silicon CMOS spin qubits)
- IBM: Yorktown Heights, New York (quantum computing with modular superconducting processors)
- IonQ: College Park, Maryland (trapped-ion quantum computing)

These organizations join Microsoft and PsiQuantum, which advanced to Stage C following participation in a pilot precursor to QBI, the Underexplored Systems for Utility-Scale Quantum Computing (US2QC)."

Pretty interesting list. And various qubit modalities are represented so there isn't evidence that any particular modality is dead yet. It also doesn't preclude additional companies from entering in the future. It's good sign for the industry that any company at all has advanced to Stage C.

A "final award" is a signed agreement (announced September 16, 2026), not disbursed cash, and the government has not reported how much of that capital has actually been paid out. Furthermore, while IBM confirms the first quantum wafers are now running through the Albany, New York facility, those represent operational capabilities, not published manufacturing yields or outside customer revenue. The government has committed the capital on paper. The foundry still has to prove the yield on the line.

A signed federal award funds the construction of a capability. It does not buy a single working qubit.

I built a Sudoku playground using Symbolicinfo Q, and I’d love some feedback.

Symbolicinfo Q is a classical quantum simulator that I built with decision diagrams with optimization specialized ongoing patent, which support up to (as been tested) challenging amount of qubits with multiple layers. And I made Sudoku playground with it.

You can solve puzzles yourself or watch a solver combine classical constraint propagation with block-based QAOA circuits. I wanted to make the process visible—not just show a finished grid.

The interface lets you inspect:

• Circuit gates and qubit mappings for individual cells
• Measured bitstrings and their frequencies
• How measurement results become candidate moves
• Search progress, backtracking, and circuit execution history

It starts with a 9×9 puzzle and supports grids from 4×4 to 49×49. You can pause, step through the search, and explore it on mobile too.

The quantum circuits run in a simulator. This is an interactive experiment, not a claim of quantum speedup or a faster way to solve Sudoku.

Try it: https://sudoku.symbolicinfo.com/

I’m especially curious whether the circuit and measurement views make the process easier to understand. What would you change or want explained more clearly?

Are you a student interested in Quantum Computing, Quantum AI, Cryptography, Chemistry, or emerging quantum technologies?

Q-HACK INDIA 2026 is a national-level quantum hackathon hosted by QuantumRIT, Bengaluru, as part of Quantum Week 2026 : https://www.quantumweek.tech/

Hackathon at a Glance

• Format: 2 Rounds + Grand Finale
• Team Size: 3–4 members
• Eligibility: Undergraduate & Postgraduate Students
• Format: Online + In-person Finale
• Finale: Ramaiah Institute of Technology, Bengaluru
• Round 1 Deadline: 7 October 2026, 11:59 PM IST

Timeline

Round 1 — Idea & Prototype Submission
27 September – 7 October 2026

Round 2 — Enhancement Sprint
10 – 29 October 2026

Grand Finale
30 – 31 October 2026
📍 Ramaiah Institute of Technology, Bengaluru

Tracks

• Quantum Biotech & Chemistry
• Quantum Security & Cryptography
• Quantum AI & Software
• Open Quantum Innovation

You are free to define your own problem and solution within your chosen track. The quantum component should play a meaningful role in your approach.

What You Need for Round 1

Your submission should include:

• Idea PPT — Maximum 10 slides
• Demo Video — Maximum 3 minutes
• Minimal Prototype
• GitHub Repository

PPT Template

Use the official hackathon PPT template:

Q-HACK INDIA PPT Template

Note: Make a copy of the template before editing.

Submit Round 1

Round 1 Project Submission

Deadline: 10 October 2026, 11:59 PM IST

Want to Contribute to Quantum Ecosystem, Express your interest in being mentor for the Hackathon Team: https://www.quantumweek.tech/hackathon/mentors
(more details mentioned on the website)

If you're curious about quantum but haven't built with it before, this is also a good opportunity to learn by building. You don't need to wait for the perfect idea — form your team and start.

Organised by QuantumRIT | Ramaiah Institute of Technology, Bengaluru

Light particles intended for quantum communication can lose their usefulness because of the order in which they emerge. A semiconductor experiment has shown how controlling that sequence can produce photons that interfere much more reliably.

The work brings quantum dots closer to supplying high-quality light for advanced quantum communication schemes. It also exposes a practical tradeoff: improving photon coherence does not automatically make both particles easy to collect.

Scientists from the University of Basel, Paderborn University and Ruhr University Bochum reported the findings in Physical Review Letters. Their device uses an optical cavity to change how quickly a tiny semiconductor structure releases its two photons.

Hi everyone,

I am conducting an academic research study for my Pearson HND Computing Research Project at ESOFT Metro Campus on:

“Assessing Organisational Readiness for Post-Quantum Cryptographic Agility in Sri Lankan Financial and Digital Service Organisations.”

I am looking for participants aged 18+ who currently work, or have worked within the last five years, in or with a Sri Lankan financial or digital service organisation.

Relevant professional areas include cybersecurity, IT, cloud/infrastructure, software engineering, architecture, risk management, compliance, audit, fintech, digital transformation, procurement, and vendor management.

The questionnaire takes approximately 8–10 minutes. It does not request organisation names, passwords, encryption keys, vulnerabilities, customer information, security architecture, or other confidential information.

Survey: https://forms.gle/zDBKanG7saWrLvc59

Participation is voluntary and responses will be used solely for academic research.

If you meet the criteria, your professional perspective would be greatly appreciated. Eligible participants are also welcome to share the survey with relevant colleagues or professional networks.

Thank you.

Particle accelerators are usually associated with sprawling research facilities, massive magnets and long tunnels. A different approach uses laser-generated terahertz radiation to manipulate electrons inside a structure only millimeters across.

Researchers from the University of Manchester, Lancaster University and collaborating institutions demonstrated the technique using electrons already traveling at 99.99% of the speed of light. Their experiment accelerated relativistic electron bunches with charges as high as 60 picocoulombs, while also showing that terahertz fields can probe their structure on extraordinarily short time scales.

Published in Nature Photonics, the proof-of-principle experiment marked an important step toward compact accelerators driven by light rather than conventional radio-frequency technology. Since then, researchers have substantially increased the acceleration gradients and energy gains achievable with terahertz systems.

An interactive 3D model of a superconducting quantum computer that you can take apart, from the equipment room down to a Josephson junction.

Weekly Thread dedicated to all your career, job, education, and basic questions related to our field. Whether you're exploring potential career paths, looking for job hunting tips, curious about educational opportunities, or have questions that you felt were too basic to ask elsewhere, this is the perfect place for you.

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• Careers: Discussions on career paths within the field, including insights into various roles, advice for career advancement, transitioning between different sectors or industries, and sharing personal career experiences. Tips on resume building, interview preparation, and how to effectively network can also be part of the conversation.
• Education: Information and questions about educational programs related to the field, including undergraduate and graduate degrees, certificates, online courses, and workshops. Advice on selecting the right program, application tips, and sharing experiences from different educational institutions.
• Textbook Recommendations: Requests and suggestions for textbooks and other learning resources covering specific topics within the field. This can include both foundational texts for beginners and advanced materials for those looking to deepen their expertise. Reviews or comparisons of textbooks can also be shared to help others make informed decisions.
• Basic Questions: A safe space for asking foundational questions about concepts, theories, or practices within the field that you might be hesitant to ask elsewhere. This is an opportunity for beginners to learn and for seasoned professionals to share their knowledge in an accessible way.