Entangled Code

Production AI Engineering • Physics-Grade Rigour

David Coldeira builds agentic LLM systems that run in production — tool-use over live databases, self-hosted fine-tuned models, local-first inference. Plus quantum computing research (QRL).

Putting an LLM on a Production Database, Read-Only by Construction

AI engineering
LLM
agentic systems
security
databases

An assistant with database access is a privilege-escalation problem wearing a chat interface. Four independent layers, only one of which actually matters — and why the prompt is the layer you should trust least.

Sep 16, 2026
5 min

Don’t Let the Model Do the Physics

AI engineering
LLM
agentic systems
sandboxing
evaluation

An assistant that answers quantum mechanics questions in plain English, in which the language model never computes anything. It writes code against a verified engine, the sandbox refuses its imports, and every answer is checkable against closed-form theory.

Sep 16, 2026
5 min

Quantum Effects in Photosynthesis Are Real — and They Compute

quantum computing
QRL
quantum biology
entanglement
photosynthesis

Photosynthesis achieves near-perfect energy transfer efficiency. The reason involves quantum coherence, entanglement between chromophores, and a counterintuitive phenomenon: environmental noise makes quantum transport more efficient, not less.

Mar 11, 2026
5 min

Beating the Standard Quantum Limit

quantum computing
QRL
quantum sensing
metrology
entanglement

The SQL and Heisenberg limit are not engineering targets — they are theorems about entanglement. Here is why GHZ states saturate the Heisenberg limit, and what quantum Fisher information actually measures.

Mar 9, 2026
7 min

A Covalent Bond Is a Quantum Relation

quantum computing
QRL
quantum chemistry
entanglement
molecular physics

Quantum chemistry has a concept called correlation energy — the part of the molecular energy that Hartree-Fock gets wrong. It turns out this is exactly orbital entanglement. Not an analogy. The same thing.

Mar 7, 2026
6 min

Bell’s Theorem and the GHZ Paradox: Entanglement Is Not Optional

quantum computing
QRL
quantum foundations
entanglement
Bell inequality

Bell’s theorem does not say quantum mechanics is weird. It says local realism is wrong — provably, experimentally, with no loopholes. The GHZ paradox makes the same point in a single measurement. Here is the physics and the computation.

Mar 5, 2026
6 min

QRL Was Already Doing Quantum Causal Reasoning (It Just Didn’t Know It)

quantum computing
QRL
quantum foundations
causal models
MBQC
quantum AI

QRL was designed to describe correlations rather than prescribe operations. It turns out this is structurally identical to a well-developed theory in quantum foundations — and the implications go further than I expected.

Mar 3, 2026
7 min

Quantum Correlations Without Gates: Verifying Bell and GHZ in QRL

quantum computing
QRL
Bell inequality
CHSH
GHZ
Mermin inequality
quantum foundations
QPL 2026

Can a relational formalism naturally express the correlations that matter for entanglement verification? QRL’s physics layer implements CHSH and Mermin tests by describing relations, not building circuits.

Feb 16, 2026
8 min

Stage 4: QRL Runs on Photonic Cloud

quantum computing
QRL
photonic QC
MBQC
Perceval
graphix
Quandela
cloud

QRL programs now run on Quandela Cloud. Built a direct path-encoded converter to bypass the polarization/path encoding mismatch. Bell state verified on sim:belenos.

Jan 29, 2026
9 min

Stage 3: Adaptive Corrections and Teleportation

quantum computing
QRL
MBQC
teleportation
adaptive corrections

QRL now tracks measurement outcomes and applies Pauli corrections automatically. Stage 3 completes the MBQC compiler with working quantum teleportation.

Jan 25, 2026
3 min

Published on Zenodo + Renamed to QRL

quantum computing
QRL
publishing
open science
Zenodo

Two major updates: The project is now officially published on Zenodo with DOI 10.5281/zenodo.18292199, and we’ve renamed from QPL to QRL (Quantum Relational Language) to avoid confusion with existing academic work.

Jan 18, 2026
3 min

QRL Meets Photonics: The First Relations-Based Compiler for Photonic Quantum Computers

quantum computing
QRL
photonic QC
MBQC
Quandela
Perceval
graphix
hardware

Photonic quantum computers are MBQC-native. QRL’s relations-first approach compiles directly to photonic circuits, bypassing gate decomposition entirely. This changes everything.

Jan 15, 2026
15 min

Stage 2 Complete: QRL Now Compiles to MBQC Patterns

quantum computing
QRL
MBQC
quantum teleportation
compiler
measurement patterns

The MBQC compiler is working! QRL now extracts graph states, generates measurement patterns, and performs quantum teleportation with adaptive corrections. Here’s what changed and why it matters.

Jan 12, 2026
10 min

Why QRL is Adopting Measurement-Based Quantum Computing

quantum computing
QRL
MBQC
research
quantum foundations

Gates are not how quantum mechanics works. QRL is adopting Measurement-Based Quantum Computing (MBQC) as its compilation target—not because it’s easier, but because it’s what the physics actually says. Here’s the theory, the motivation, and the research program ahead.

Jan 2, 2026
14 min

Stage 1: Scaling Relations-First Quantum Programming to n Qubits

quantum computing
QRL
physics
GHZ states
entanglement
tensor networks

Stage Zero proved relations-first quantum programming works for 2 qubits. Stage 1 scales to arbitrary n-qubit systems with GHZ states, W states, and proper tensor algebra. Here’s what changed and why it matters.

Dec 31, 2025
19 min

Stage Zero: Programming Quantum Reality Through Relations, Not Gates

quantum computing
QRL
physics
programming languages
research

Most quantum frameworks force you to think in gates. QRL Stage Zero proves you can build from entanglement instead. Here’s why relations-first quantum programming might unlock something bigger.

Dec 29, 2025
13 min

Quantum Computing Foundations: The Theory Behind QRL

quantum computing
theory
physics
tutorial

A comprehensive guide to the quantum mechanics you need to understand relations-first quantum programming. From superposition to entanglement entropy.

Dec 13, 2025
9 min
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