QuantumX: an experience for the consolidation of Quantum Computing and Quantum Software Engineering as an emerging discipline

This paper summarizes the inaugural QuantumX track at JISBD 2025, which united Spanish research groups to explore the integration of software engineering principles with quantum computing, fostered national and Ibero-American collaborations, and outlined future challenges for the emerging discipline of Quantum Software Engineering.

The Gist

Imagine a massive, high-tech construction site. For decades, the architects (physicists and mathematicians) have been building the blueprints for a new kind of skyscraper called Quantum Computing. These buildings are incredibly powerful, capable of solving problems that would take normal computers thousands of years to finish.

However, there's a problem: the construction workers (software engineers) are still trying to figure out how to build these skyscrapers without the whole thing collapsing. They don't have standard tools, safety codes, or reliable blueprints yet.

This paper is a report card from a very special meeting called QuantumX, held in Spain in 2025. It's like a "Town Hall" where the best construction crews in the country gathered to say, "Okay, we have the physics; now let's figure out the engineering."

Here is the breakdown of what happened, explained simply:

1. The Big Problem: Building with "Spooky" Bricks

Normal computers are like a light switch: it's either ON or OFF.
Quantum computers are like a spinning coin. It's ON, OFF, and spinning all at the same time. This makes them super powerful, but also incredibly fragile and hard to control.

The people at the QuantumX meeting realized that we can't just keep writing code like we did for the old computers. We need a new set of rules, new tools, and a new way of thinking. They call this new discipline Quantum Software Engineering.

2. The "Toolbox" Upgrades

The researchers presented many different ideas on how to make building these quantum skyscrapers easier and safer. Think of these as new tools for the workers:

• The Traffic Cop (Orchestration): Imagine a busy airport where planes (quantum circuits) are trying to land on a runway that is often foggy (noisy hardware). One group built a "Traffic Cop" system that decides which plane lands when, which runway to use, and how to group them together so no one wastes fuel or time. This saves money and reduces crashes.
• The Lego Kit (Abstraction): Right now, building a quantum program is like trying to build a house by welding individual atoms together. It's too hard! Several groups proposed creating "Lego bricks" (high-level abstractions). Instead of welding atoms, engineers can just snap pre-made blocks together. This makes the code easier to read, fix, and reuse.
• The Quality Inspector (Testing & Metrics): How do you know your quantum house is safe? One group built a "Quality Inspector" robot. It checks the code for errors, measures how "tangled" the logic is, and even creates "mutant" versions of the code (like breaking a brick on purpose) to see if the building holds up. They found that this saves a massive amount of money on testing.
• The Hybrid Bridge: Since we can't build a whole quantum city overnight, we need bridges. Several groups showed how to build "Hybrid" systems where the heavy lifting is done by the quantum computer, but the normal computer handles the rest. It's like having a race car engine (quantum) inside a reliable family sedan (classical).

3. The Teamwork: "Many Hands Make Light Work"

One of the most important parts of the meeting wasn't just the tools, but the people.

• The Network: The paper highlights two big clubs: RIPAISC (a group connecting Spain, Portugal, and Latin America) and QSpain (the national team).
• The Analogy: Imagine if every construction crew in the country decided to stop working in secret and started sharing their blueprints, tools, and mistakes. That's what these networks are doing. They are making sure that if one group figures out how to fix a leaky quantum roof, everyone else learns how to do it too.

4. The Real-World Results

The meeting wasn't just theory. They showed working prototypes:

• Medical Texts: Using quantum power to read complex lung cancer reports faster and more accurately than before.
• Database Speed: Trying to use quantum tricks to find information in massive databases instantly (like finding a needle in a haystack, but the haystack is the size of the ocean).
• Image Processing: Using quantum math to analyze images, though they admitted this area still needs more rigorous testing to prove it actually works better than normal methods.

5. The Bottom Line: Spain is Ready to Build

The main takeaway of this paper is that Spain has become a major player in this field.

• They aren't just watching from the sidelines; they are actively building the tools, writing the rules, and training the next generation of engineers.
• They realized that for quantum computing to become a real product (like the iPhone or the Internet), we need Software Engineers just as much as we need Physicists.

In a nutshell:
The QuantumX meeting was the moment the "Quantum Revolution" grew up. It moved from "Look at this cool magic trick!" to "Here is how we build a reliable, safe, and useful product." It was a celebration of teamwork, a showcase of new tools, and a promise that the future of computing is being engineered right now, brick by brick.

Technical Summary

Based on the provided paper, here is a detailed technical summary of the QuantumX track and the associated research contributions.

1. Problem Statement

The paper addresses the critical gap between the rapid theoretical and hardware advancements in Quantum Computing (QC) and the lack of mature Software Engineering (SE) practices required to build reliable, scalable, and maintainable quantum software.

• The Challenge: Quantum computing is in a transitional "NISQ" (Noisy Intermediate-Scale Quantum) era. While hardware is becoming accessible, the software development lifecycle lacks standardized methodologies for quality assurance, testing, orchestration, abstraction, and governance.
• The Need: There is an urgent need to adapt classical SE principles (e.g., modularity, testing, service engineering, quality metrics) to the quantum paradigm to facilitate industrial adoption, ensure reliability, and bridge the gap between physicists, computer scientists, and software engineers.
• Context: The paper highlights the fragmentation of the Spanish research community and the need for a unified forum to consolidate efforts in Quantum Software Engineering (QSE).

2. Methodology

The paper does not present a single experimental study but rather a structured synthesis and critical analysis of the first edition of the QuantumX track, held within the JISBD 2025 conference.

• Event Analysis: The authors analyzed contributions from 11 major Spanish research groups (e.g., Quercus, Alarcos, SCORE Lab, ITIS, PAPC, etc.) representing diverse disciplines (SE, AI, HPC, Databases, Robotics).
• Thematic Categorization: The contributions were categorized into key engineering domains:
  • Abstraction & Programming Models: Moving from gate-level to high-level constructs.
  • Service Engineering & Orchestration: Managing hybrid quantum-classical services and multi-cloud execution.
  • Quality & Testing: Developing metrics, mutation testing, and validation frameworks.
  • Hybrid Architectures & Applications: Integrating QC into AI, databases, and cybersecurity.
• Network Integration: The methodology included the presentation and analysis of two strategic networks: RIPAISC (Ibero-American) and QSpain (National), to assess the state of community collaboration.

3. Key Contributions

The paper synthesizes specific technical contributions from the participating groups, categorized by their engineering focus:

A. Abstraction and Programming Languages

• Quantum Integers & Oracles (Quercus/SCORE): Proposed a new data type ("quantum integer") and composable oracles (e.g., Less-Than, Greater-Than) to raise the abstraction level beyond raw gates, promoting modularity and reuse.
• Locus Abstraction (Quercus/ITIS): Introduced "Locus," a lightweight abstraction layer for circuit-based programming. It acts as a bridge between low-level gates and high-level operations, aiming to create Domain Specific Languages (DSLs) and reusable component libraries.
• Grover Oracle Synthesis (Alarcos): Developed an algorithm to synthesize Grover oracles from binary matrices, automating circuit generation and reducing design friction.

B. Service Engineering, Orchestration, and Governance

• QCRAFT Scheduler (Quercus): Defined planning policies to group and combine quantum circuits on cloud QPUs. This reduces waiting times and costs by batching tasks.
• Qrchestrator (SCORE Lab): An error-and-load-aware orchestrator for multi-NISQ providers. It dynamically selects the best backend based on workload and hardware fidelity, reducing failed executions.
• Hybrid Service Governance (SCORE/Alarcos): Proposed frameworks for HSaaS (Hybrid Software-as-a-Service), utilizing smart contracts and self-adaptive policies to manage pricing, load, and quality in hybrid quantum-classical environments.
• ATHENA-HARMONIA: A subproject integrating quantum and classical components under a "cloud-edge-quantum" continuum, aiming for unified governance.

C. Quality Assurance, Testing, and Metrics

• Quantum Mutation Testing (Quercus/Alarcos): Developed a tool to execute quantum circuit mutants on real hardware using task planning. Achieved cost reductions of up to 94% compared to individual executions, proving the feasibility of large-scale testing in the NISQ era.
• Analyzability Quality Model (Alarcos): Validated a quality model for hybrid systems based on ISO/IEC 25010, combining classical metrics with quantum-specific metrics (e.g., circuit depth, complexity).
• LazyQML (CSIC/QHPC): A lightweight Python package for benchmarking Quantum Machine Learning (QML) models, standardizing metrics (e.g., balanced accuracy) and reducing friction in model comparison.

D. Hybrid Applications and Optimization

• Quantum Image Processing (ROBÓTICA): A critical review highlighting the lack of rigor in current literature (poor reproducibility, tiny datasets) and advocating for standardized benchmarks.
• Quantum Databases (COGRADE): A roadmap for integrating quantum algorithms (e.g., Grover) into DBMS for indexing and query optimization, focusing on hybrid classical-quantum approaches.
• Tensor Networks for QML (PAPC): Evaluated the use of Tensor Networks (MPS/PEPS) to simulate and train quantum neural networks efficiently, reducing computational resources compared to dense simulation.
• Clinical Text Classification (eVIDA): A hybrid model combining 1D CNNs with Quantum BiLSTM and attention layers, showing improved F1 scores in lung cancer report classification.
• Graph Coloring Optimization (DSIE): Optimized Grover oracles for graph coloring using register-based counters to reduce circuit depth and gate count.

4. Results

• Cost Efficiency: The QCRAFT Scheduler demonstrated an average 84% reduction in cost and task execution time. The Quantum Mutation Testing tool achieved up to 94% cost reduction on IBM Quantum hardware.
• Performance Gains: The hybrid clinical text classification model outperformed classical baselines in F1 and MCC metrics. Tensor Network simulations showed significant resource savings for specific QML tasks.
• Community Consolidation: The event successfully unified 11 diverse research groups, fostering cross-disciplinary collaboration (e.g., SE + Physics + AI).
• Strategic Alignment: The presentation of RIPAISC and QSpain confirmed the existence of a structured network for Ibero-American and European collaboration, positioning Spain as an emerging contributor to the global quantum ecosystem.

5. Significance

• Discipline Consolidation: The paper marks a pivotal moment in the maturation of Quantum Software Engineering as a distinct discipline. It moves the field from purely theoretical physics discussions to practical engineering concerns (testing, orchestration, quality models).
• National Leadership: It establishes Spain as a key player in the European quantum landscape, demonstrating a robust, multidisciplinary research ecosystem capable of delivering tangible tools and prototypes.
• Bridging the Gap: By focusing on abstractions (like Locus and Quantum Integers) and service engineering, the work directly addresses the "usability" barrier, making quantum computing accessible to software engineers who may not be quantum physicists.
• Future Roadmap: The paper identifies open challenges, including the need for standardized benchmarks, better high-level languages, and the systematic integration of SE practices into the quantum lifecycle. It advocates for the QuantumX track to become a recurring forum to sustain this momentum.

In conclusion, the paper serves as both a state-of-the-art report on the Spanish quantum software landscape and a call to action for the global community to prioritize engineering rigor alongside hardware development to ensure the sustainable growth of quantum technologies.