1f:I[80718,["/_next/static/immutable/chunks/3lt7t0nu_ly9n.js","/_next/static/immutable/chunks/2fiudfqkvf43z.js","/_next/static/immutable/chunks/1ap93zgtlmsug.js","/_next/static/immutable/chunks/3kynn6d0ykii1.js"],"default"] 20:T1e8a,# strange [![Build](https://github.com/redfx-quantum/strange/actions/workflows/build.yml/badge.svg)](https://github.com/redfx-quantum/strange/actions/workflows/build.yml) [![Test Coverage](https://github.com/redfx-quantum/strange/blob/gh-pages/badges/jacoco.svg?raw=true)](https://redfx-quantum.github.io/strange/) [![Maven Central](https://img.shields.io/maven-central/v/org.redfx/strange)](https://search.maven.org/#search|ga|1|org.redfx.strange) [![License](https://img.shields.io/github/license/redfx-quantum/strange)](https://opensource.org/licenses/GPL-3.0) [![javadoc](https://javadoc.io/badge2/org.redfx/strange/javadoc.svg)](https://javadoc.io/doc/org.redfx/strange) # Quantum Computing API and simulator for Java This project defines a Java API that can be used to create Quantum Programs. A Quantum Program, defined by org.redfx.strange.Program can be executed on an implementation of the org.redfx.strange.QuantumExecutionEnvironment. You can read more about Java and QuantumComputing in [Quantum Computing in Action](https://www.manning.com/books/quantum-computing-in-action?a_aid=quantumjava&a_bid=e5166ab9) ![qcj](https://github.com/redfx-quantum/strange/assets/767876/324f682d-eaaf-4829-b411-4ab2abc104cc) ## Core Concepts The following diagram depicts the core components of the Strange quantum computing library. A `QuantumExecutionEnvironment` executes a `Program`, which is composed of `Step`s and uses some `Qubit`s. Each `Step` contains `Gate`s that operate on the `Qubit`s defined for the `Program`. ```mermaid classDiagram direction LR class QuantumExecutionEnvironment { <> +runProgram(Program) Result } class Program { -numberQubits: int -steps: List~Step~ +addStep(Step) } QuantumExecutionEnvironment ..> Program : executes Program "1" o-- "0..*" Step class Step { -gates: List~Gate~ +addGate(Gate) } Step "1" o-- "0..*" Gate class Gate { <> +getAffectedQubitIndexes() List~Integer~ } Program "1" -- "1..*" Qubit : operates on Gate "1" -- "1..*" Qubit : operates on class Qubit { } ``` # Getting Started Strange is distributed via Maven Central and can thus easily be used leveraging maven or gradle build software. ## Using JBang JBang makes it easy to run simple Java applications without setup hassle. You can download JBang from jbang.dev. The following code is a very simple Java application that is using Strange (and StrangeFX). Save this code in a file named ShortStrangeDemo.java and execute it by typing the following command in a terminal: `jbang ShortStrangeDemo.java` ``` //DEPS org.redfx:strangefx:0.1.4 import org.redfx.strange.*; import org.redfx.strange.gate.*; import org.redfx.strange.local.SimpleQuantumExecutionEnvironment; import org.redfx.strangefx.render.Renderer; import java.util.Arrays; public class ShortStrangeDemo { public static void main(String[] args) { Program p = new Program(2, new Step(new X(0)), new Step(new Hadamard(0), new X(1))); SimpleQuantumExecutionEnvironment sqee = new SimpleQuantumExecutionEnvironment(); Qubit[] qubits = sqee.runProgram(p).getQubits(); Renderer.renderProgram(p); Arrays.asList(qubits).forEach(q -> System.out.println("qubit with probability on 1 = "+q.getProbability()+", measured it gives "+ q.measure())); } } ``` The result of this is some output to the terminal, and a Window showing the Quantum Circuit you created: ``` qubit with probability on 1 = 0.4999999701976776, measured it gives 1 qubit with probability on 1 = 0.9999999403953552, measured it gives 1 ``` (note that the first qubit can be measured as `0` or as `1`) ![demo output](assets/shortdemo.png) ## Using maven A typical `pom.xml` file looks as follows: ```maven 4.0.0 org.redfx.javaqc simplestrangedemo jar 1.0-SNAPSHOT SimpleStrangeDemo http://maven.apache.org org.redfx strange 0.1.3 org.openjfx javafx-maven-plugin 0.0.8 SimpleStrangeDemo ``` ## Using gradle A typical build.gradle file looks as follows: ```gradle plugins { id 'application' } repositories { mavenCentral() } dependencies { implementation 'org.redfx:strange:0.1.1' } mainClassName = 'SimpleStrangeDemo' ``` # About the sample application. The code pasted above in the `ShortStrangeDemo` snippet is a short version of the code below. Both applications are similar, but the code below is more verbose which makes it easier to explain what is going on. ```java import org.redfx.strange.*; import org.redfx.strange.gate.*; import org.redfx.strange.local.SimpleQuantumExecutionEnvironment; import java.util.Arrays; public class SimpleStrangeDemo { public static void main(String[] args) { Program p = new Program(2); Gate xGate1 = new X(0); Step step1 = new Step(); step1.addGate(xGate1); p.addStep(step1); Gate hGate2 = new Hadamard(0); Gate xGate2 = new X(1); Step step2 = new Step(); step2.addGates(hGate2, xGate2); p.addStep(step2); SimpleQuantumExecutionEnvironment sqee = new SimpleQuantumExecutionEnvironment(); Result res = sqee.runProgram(p); Qubit[] qubits = res.getQubits(); Arrays.asList(qubits).forEach(q -> System.out.println("qubit with probability on 1 = "+q.getProbability()+", measured it gives "+ q.measure())); } } ``` This sample create a Program that requires 2 qubits. It will create 2 steps (s and t). The first step adds a Paul-X (NOT) Gate to the first qubit. The second steps adds a Hadamard Gate to the first qubit, and a NOT gate to the second qubit. Both steps are added to the Program. In order to "run" this program, we need a QuantumExecutionEnvironment. Strange comes with a SimpleQuantumExecutionEnvironment which contains a very simple, non-optimized quantum computer simulator. After running the program on this simulator, we inspect the state of the Qubits. As expected, there is a 50% chance the first qubit (which had an X and an H gate) will be in the 0 state, and a 50% chance it will be in the 1 state. The second qubit will always be in the 1 state. Running this application a number of times will consistently give the same probabilities, and different measurements. # Visualization The Strange API's allow creating and simulate quantum programs. A companion project, [StrangeFX](https://github.com/redfx-quantum/strangefx) , allows visualising programs, and create them with a simple drag and drop interface. The sample program above rendered via StrangeFX looks as follows: ![StrangeFX rendering](https://github.com/redfx-quantum/strangefx/blob/master/docs/images/simpleview.png) # More samples You can find more samples at https://github.com/johanvos/quantumjava 16:["$","$L1f",null,{"user":{"username":"redfx-quantum","displayName":"Redfx Quantum","bio":null,"location":null,"githubUrl":"https://github.com/redfx-quantum","avatar":null,"memberSince":null,"stats":{"algorithms":1,"totalStars":237,"totalForks":58,"contributions":1}},"userRepos":[{"id":"redfx-quantum-strange","slug":"redfx-quantum-strange","type":"simulator","name":"strange","description":"Quantum Computing API for Java","summary":"$undefined","useCases":[],"fullName":"redfx-quantum/strange","githubUrl":"https://github.com/redfx-quantum/strange","author":"redfx-quantum","authorType":"organization","metadata":{"framework":null,"frameworks":[],"taskType":null,"tags":[],"hardwareCompatibility":[],"qubitRequirement":null,"license":"BSD-3-Clause","installCommand":"$undefined","maturity":"$undefined"},"stats":{"stars":237,"forks":58,"downloads":0,"runs":0,"lastUpdated":"2025-11-14T21:26:02Z","createdAt":"2018-03-26T16:06:29Z"},"features":{"verified":false,"trending":false,"featured":false},"version":"1.0.0","readme":"$20","benchmarks":[],"papers":[]}]}]

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