Quantum4J – A Pure Java Quantum Computing SDK

Hacker News

I built Quantum4J because I couldn’t find a clean, dependency-free way to experiment with multi-qubit unitaries from Java. Most QC libraries target Python, so this is meant to bring quantum circuit construction and state-vector simulation to the JVM. It includes: - state-vector simulator (~25 qubits) - standard gates (X, Y, Z, H, S, T, RX/RY/RZ, CX, CZ, SWAP, ISWAP, CCX) - measurement + classical registers - OpenQASM 2.0 exporter Example: QuantumCircuit.create(2).h(0).cx(0,1).measureAll(); Would love feedback on the architecture, gate engine, or ideas for what to add next. Iam considering expanding Quantum4J into a more complete JVM quantum tooling ecosystem. Interested in feedback from practitioners or researchers using Java in QC or simulation.

Visit product View on Hacker NewsNov 20, 2025

Share card

Actual performance

1points

1comments

Did not reach leaderboard

Launch Intel predictions

Analyze your own launch →

Indie HackersFits the IH revenue-focused audience · Missing: supports, reddit linkedin, podcasting

72%72% predicted probability of success on Indie Hackers, based on ML models trained on real launch data.

best fitHighest predicted score across all platforms for this description.

Product HuntOn track for Day 1 leaderboard · Strong signals: using, open · Missing: mac, agents, macos

54%54% predicted probability of success on Product Hunt, based on ML models trained on real launch data.

AppSumoMay struggle as an AppSumo deal · Missing: plus, platform, intuitive

47%47% predicted probability of success on AppSumo, based on ML models trained on real launch data.

Hacker NewsMay not resonate with HN audience · Strong signals: ide, io · Missing: https docs, excited, just released

42%42% predicted probability of success on Hacker News, based on ML models trained on real launch data.

nativeThis product was originally launched on this platform.

TrustMRRLess likely to generate early MRR · Strong signals: way · Missing: mobile apps, ios, personal

37%37% predicted probability of success on TrustMRR, based on ML models trained on real launch data.

Acquire.comPre-revenue stage for this audience · Missing: arr, mrr, revenue

18%18% predicted probability of success on Acquire.com, based on ML models trained on real launch data.

BetaListMay not resonate with beta-testers · Missing: web3, chat, crypto

3%3% predicted probability of success on BetaList, based on ML models trained on real launch data.

Correct prediction on native model

Similar products

Scotty: Quantum Computing in Scala45%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

Scotty: Quantum Computing in Scala

Hacker News2

Quantum Computing – An Applied Approach60%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

Quantum Computing – An Applied Approach

Hacker News3

Quantum Computing – System42%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

Quantum computing for the modern innovator

Product Hunt+5

It's Elementary: Meet Quantum Computing [pdf]45%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

It's Elementary: Meet Quantum Computing [pdf]

Hacker News4

Quantum Computing Notes, with focus on IBM Q [pdf]48%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

Quantum Computing Notes, with focus on IBM Q [pdf]

Hacker News1

Quantum Lings – A LeetCode-style platform for quantum computing52%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

Quantum Lings – A LeetCode-style platform for quantum computing

Hacker News3

QuDotPy a quantum computing emulator in Python62%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

QuDotPy a quantum computing emulator in Python

Hacker News1

I Am Writing an A.I. and Quantum Computing Sci-Fi Novel49%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

I Am Writing an A.I. and Quantum Computing Sci-Fi Novel

Hacker News2

Quantum Computing Tool: Circuit GUI and Integrated Simulator41%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

Quantum Computing Tool: Circuit GUI and Integrated Simulator

Hacker News1

Amazon Ocelot55%Launch Intel prediction score: how likely this product is to succeed on its source platform, based on its name, tagline, and description.

Amazon's first quantum computing chip

Product Hunt+164Amazon

Browse all products Analyze your launch