VQE: The Variational Quantum Eigensolver Explained
How the variational quantum eigensolver finds ground-state energies: ansatz design, energy measurement, parameter optimization and chemistry uses.
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Quantum Algorithms
Shor, Grover, QAOA, VQE and the rest — what each quantum algorithm does, the problem it targets and where the promised speedup really comes from.
85 articles
Quantum Phase Estimation (QPE) Step by Step
Quantum phase estimation step by step: controlled unitaries, the inverse QFT, precision, error sources and its use in Shor’s algorithm and chemistry.
QAOA: The Quantum Approximate Optimization Algorithm
How QAOA works: alternating cost and mixer operators, a classical optimizer in the loop, and applications to logistics, finance and energy.
Quantum Fourier Transform (QFT): What It Does
The quantum Fourier transform explained: its circuit, its role in phase estimation and Shor’s algorithm, and how it differs from the classical FFT.
Grover’s Algorithm: Quantum Search, Explained
How Grover’s algorithm searches an unsorted list in about √N steps using an oracle and amplitude amplification, and its effect on cryptography.
Shor’s Algorithm: How Quantum Factoring Works
How Shor’s algorithm factors integers: period finding, modular exponentiation, the quantum Fourier transform and the circuit it needs.
Quantum Supremacy: What Was Actually Proved
What quantum supremacy experiments actually proved, what they did not, and how supremacy differs from useful quantum advantage.
Every Major Quantum Algorithm, Listed
The major quantum algorithms in one place: Grover, Shor, QFT, Simon, phase estimation, QAOA, quantum walks, HHL, VQE and amplitude estimation.
Quantum Algorithms: An Overview of What Exists
An overview of quantum algorithms: their history, the quantum Fourier transform, amplitude amplification, Deutsch-Jozsa, Simon and phase estimation.
Why Quantum Algorithms Depend on Qubits
How qubits make quantum algorithms possible: superposition, entanglement, interference, gates and measurement, and why coherence limits them.
Quantum Computing for Optimization Problems
How optimization problems are mapped to quantum computers, the limits of current hardware, practical approaches and early real-world applications.
Quantum Algorithms for Graph Theory Problems
Quantum approaches to graph problems: Grover search, quantum walks, QAOA, quantum annealing and algorithms for spanning trees and graph coloring.
