Reference Sitev1.0
Circuit Quantum
Electrodynamics
A self-contained reference on cQED — the study of quantum light–matter interactions realised with superconducting circuits. Built from first principles, for students and researchers who want to understand the physics, not just the results.
What's Inside
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First Principles Derivations
Every result is derived from scratch — no hand-waving. Start from the Lagrangian and arrive at the Hamiltonian step by step.
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Rendered Mathematics
All equations are typeset with KaTeX. Inline and display math render cleanly throughout every page.
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Interactive Calculators
Plug in your own parameters and compute dispersive shifts, transmon frequencies, Purcell rates, and more instantly.
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Curated Resources
Foundational papers, textbooks, research groups, and simulation tools — all linked and annotated.
Topics Covered
01→02→03→04→05→06→
cQED Overview
What is circuit QED and why it matters for quantum computing.
Jaynes–Cummings Model
Derivation of the Jaynes–Cummings Hamiltonian and its eigenstates.
Dispersive Limit
The off-resonant regime and the dispersive approximation.
Transmon Qubit
Circuit quantisation, charge dispersion, and the transmon regime.
Input-Output Theory
Coupling to external transmission lines, Purcell effect, and readout.
Lindblad Master Equation
Open quantum systems, decoherence rates T₁ and T₂.
Built as a personal reference while studying cQED. All derivations are my own — errors and omissions are mine too. If you spot a mistake, get in touch here.