QubitHub

Circuit Repository

Browse reproducible quantum circuits with rich metadata.
53 TOTAL CIRCUITS

Circuits (53)

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/bell-state-fork
00

Bell State (Fork)

Creates the Bell state |Phi+> = (|00> + |11>)/sqrt(2), the simplest demonstration of quantum entanglement. Two qubits ar...

BeginnerEntanglement+2
qiskit21
/smoke-track-a-8
00

Smoke Track A #8

Track A #8 staging smoke test

qiskit20
/expressibility
00

Expressibility Analysis

Quantifies ansatz expressiveness via fidelity sampling and KL divergence from the Haar-random distribution, comparing si...

AdvancedAnsatz+4
cirq44
/phase-estimation
00

Quantum Phase Estimation

Estimates the eigenvalue phase of a unitary operator with tuneable precision using counting qubits and the inverse QFT

AdvancedAlgorithm+4
qiskit44
/angle-encoding
10

Angle Encoding

Encodes classical features as rotation angles on the Bloch sphere, with standard (RY/RZ/RX) and dense (2 features per qu...

IntermediateMachine_Learning+4
qiskit46
/grover-search
00

Grover's Search Algorithm

Searches an unstructured database of N=4 items using Grover's algorithm, finding the marked item with 100% probability i...

IntermediateAlgorithm+4
qiskit25
/fidelity-kernel
00

Fidelity Kernel (SWAP Test)

Computes the quantum fidelity |⟨φ(x)|φ(y)⟩|² directly using the SWAP test circuit — an interferometric technique that me...

AdvancedMachine_Learning+4
pennylane56
/variational-classifier
00

Variational Quantum Classifier

A parameterized quantum circuit for binary classification — the quantum analogue of a neural network layer. Encodes 2 fe...

IntermediateMachine_Learning+4
qiskit23
/heh-plus-ground-state
00

VQE for HeH+ Ion

Finds the ground state energy of helium hydride cation (HeH+) using VQE with a UCCSD-inspired 3-parameter ansatz. HeH+ i...

IntermediateChemistry+4
qiskit25
/vqd-algorithm
00

VQD Algorithm

General-purpose VQD implementation for finding K eigenstates sequentially. Each state is found by minimizing the energy ...

AdvancedChemistry+3
qiskit46
/surface-code
00

Surface Code (Distance-3)

Topological QEC code on a 2D lattice with ~1% error threshold — the leading candidate for practical fault-tolerant quant...

IntermediateError_Correction+5
qiskit177
/quantum-kernel-svm
00

Quantum Kernel SVM

Trains a classical Support Vector Machine on a kernel matrix computed from quantum circuits. The ZZ feature map encodes ...

AdvancedMachine_Learning+4
pennylane48
/ssvqe
00

SSVQE Algorithm

Simultaneously optimizes for multiple eigenstates using a weighted cost function and orthogonality constraints. Each sta...

AdvancedChemistry+3
qiskit45
/data-reuploading
00

Data Re-uploading Classifier

Universal single-qubit classifier that re-encodes data between variational layers, proving 1 qubit suffices for any clas...

IntermediateMachine_Learning+4
qiskit14
/bernstein-vazirani
00

Bernstein-Vazirani Algorithm

Finds a hidden bit string s encoded in an oracle f(x) = s·x (mod 2) using a single quantum query. Generalizes Deutsch-Jo...

BeginnerAlgorithm+4
qiskit44
/hardware-efficient-ansatz
00

Hardware-Efficient Ansatz

Parameterized variational circuit optimized for NISQ devices, using native gate sets (RY, RZ, CZ) with configurable enta...

AdvancedAnsatz+3
cirq48
/tsp
00

QAOA for TSP

Solves the Traveling Salesman Problem using QAOA with constraint penalties. Uses city-timestep encoding (n^2 qubits for ...

IntermediateOptimization+3
qiskit43
/quantum-kernel
00

Quantum Kernel Estimation

Computes quantum kernel K(x1,x2) = |<0|U+(x2)U(x1)|0>|^2 using ZZ Feature Map for kernel-based quantum machine learning

IntermediateMachine_Learning+4
qiskit23
/projected-quantum-kernel
00

Projected Quantum Kernel

Projects quantum states to a finite-dimensional classical vector of expectation values instead of computing the full fid...

AdvancedMachine_Learning+4
pennylane47
/trainable-kernel
00

Trainable Quantum Kernel

Quantum kernel with learnable parameters optimized via kernel-target alignment (KTA). Interleaves data encoding (angle e...

AdvancedMachine_Learning+4
pennylane44