/amplitude-encoding
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Amplitude Encoding
Encodes 2^n classical values into n qubit amplitudes for exponential data compression in quantum machine learning
IntermediateMachine_Learning+4
qiskit33
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ORGANIZATION
QubitHub@qubithub•Joined 6 months ago
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/expressibility
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Expressibility Analysis
Quantifies ansatz expressiveness via fidelity sampling and KL divergence from the Haar-random distribution, comparing si...
AdvancedAnsatz+4
cirq44
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/phase-estimation
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Quantum Phase Estimation
Estimates the eigenvalue phase of a unitary operator with tuneable precision using counting qubits and the inverse QFT
AdvancedAlgorithm+4
qiskit44
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/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
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/grover-search
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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
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/fidelity-kernel
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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
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/variational-classifier
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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
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/heh-plus-ground-state
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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
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/vqd-algorithm
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VQD Algorithm
General-purpose VQD implementation for finding K eigenstates sequentially. Each state is found by minimizing the energy ...
AdvancedChemistry+3
qiskit46
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/surface-code
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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
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/quantum-kernel-svm
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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
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/ssvqe
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SSVQE Algorithm
Simultaneously optimizes for multiple eigenstates using a weighted cost function and orthogonality constraints. Each sta...
AdvancedChemistry+3
qiskit45
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/data-reuploading
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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
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/bernstein-vazirani
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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
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/hardware-efficient-ansatz
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Hardware-Efficient Ansatz
Parameterized variational circuit optimized for NISQ devices, using native gate sets (RY, RZ, CZ) with configurable enta...
AdvancedAnsatz+3
cirq48
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/tsp
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QAOA for TSP
Solves the Traveling Salesman Problem using QAOA with constraint penalties. Uses city-timestep encoding (n^2 qubits for ...
IntermediateOptimization+3
qiskit43
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/quantum-kernel
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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
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/projected-quantum-kernel
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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
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/trainable-kernel
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Trainable Quantum Kernel
Quantum kernel with learnable parameters optimized via kernel-target alignment (KTA). Interleaves data encoding (angle e...
AdvancedMachine_Learning+4
pennylane44
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/qaoa-mixer
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QAOA Mixer Ansatz
QAOA with configurable mixer unitaries for combinatorial optimization. The standard X-mixer explores all bitstrings for ...
AdvancedAnsatz+4
cirq48
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/beh2-ground-state
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VQE for BeH2 Molecule
Finds the ground state energy of beryllium hydride (BeH2) using VQE — the largest molecule in the VQE progression with 6...
IntermediateChemistry+3
qiskit64
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/bell-state
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Bell State
Creates the Bell state |Phi+> = (|00> + |11>)/sqrt(2), the simplest demonstration of quantum entanglement. Two qubits ar...
BeginnerEntanglement+2
qiskit212
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/maxcut
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QAOA for MaxCut
Solves the Maximum Cut problem using the Quantum Approximate Optimization Algorithm (QAOA). Partitions graph vertices in...
IntermediateOptimization+3
qiskit45
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/superdense-coding
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Superdense Coding
Sends 2 classical bits using 1 qubit by leveraging a pre-shared Bell pair. The dual of quantum teleportation — demonstra...
BeginnerCommunication+2
qiskit23
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/hadamard-test
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Hadamard Test
Estimates the complex expectation value <psi|U|psi> of a unitary operator using quantum interference on an ancilla qubit...
IntermediateUtility+3
qiskit24
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/lih-excited-states
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LiH Excited States
Finds ground and first excited states of lithium hydride (LiH) using VQD on a 4-qubit active-space Hamiltonian. LiH has ...
AdvancedChemistry+3
qiskit44
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/vqe-h2-peruzzo
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VQE H2 (Peruzzo 2014)
Reproduction of the first experimental VQE demonstration — finding the ground-state energy of H2 on a photonic quantum p...
AdvancedResearch+4
qiskit25
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/quantum-teleportation
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Quantum Teleportation
Teleports an unknown quantum state from one qubit to another using a shared Bell pair and two classical bits. Demonstrat...
BeginnerCommunication+2
qiskit33
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/uccsd-ansatz
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UCCSD Ansatz
Unitary Coupled Cluster Singles and Doubles (UCCSD) ansatz — the gold-standard variational wavefunction for quantum chem...
AdvancedAnsatz+3
cirq45
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/multistate-vqe
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Multistate VQE
Multi-reference approach for finding multiple eigenstates simultaneously by building a contracted Hamiltonian in a subsp...
AdvancedChemistry+3
qiskit46
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/kernel-alignment
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Kernel-Target Alignment
Optimizes quantum kernel parameters to maximize centered kernel-target alignment (CKA) — a principled score measuring ho...
AdvancedMachine_Learning+5
pennylane46
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/h2-excited-states
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H2 Excited States (VQD)
Finds both ground and first excited states of the hydrogen molecule (H2) using Variational Quantum Deflation (VQD) — a s...
AdvancedChemistry+4
qiskit24
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/h2-ground-state
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VQE for H2 Molecule
Finds the ground state energy of the hydrogen molecule (H2) using the Variational Quantum Eigensolver (VQE) — a hybrid q...
IntermediateChemistry+3
qiskit25
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/quantum-advantage-kernel
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Quantum Kernel Advantage (Huang 2021)
Reproduction of "Power of data in quantum machine learning" (Huang et al., Nature Communications 12, 2631, 2021). Demons...
AdvancedResearch+4
qiskit43
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/knapsack
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QAOA for Knapsack
Solves the 0/1 Knapsack problem using the Quantum Approximate Optimization Algorithm (QAOA) with QUBO penalty method. Se...
IntermediateOptimization+3
qiskit33
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/phase-flip-code
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3-Qubit Phase Flip Code
Corrects single Z (phase flip) errors using Hadamard-basis encoding — dual of the bit-flip code
IntermediateError_Correction+3
qiskit35
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/qaoa-maxcut-farhi
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QAOA MaxCut (Farhi 2014)
Faithful reproduction of the Quantum Approximate Optimization Algorithm (QAOA) for MaxCut, as introduced in the foundati...
AdvancedResearch+4
cirq45
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/portfolio-optimization
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QAOA for Portfolio
Optimizes asset portfolio selection using the Quantum Approximate Optimization Algorithm (QAOA). Encodes the Markowitz m...
IntermediateOptimization+3
qiskit44
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/bit-flip-code
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3-Qubit Bit Flip Code
The simplest quantum error correcting code: encodes 1 logical qubit into 3 physical qubits (+ 2 syndrome ancillae) to de...
IntermediateError_Correction+3
qiskit34
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/steane-code
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Steane's 7-Qubit Code
[[7,1,3]] CSS code based on Hamming [7,4,3] — corrects any single-qubit error with transversal H, CX, S gates
IntermediateError_Correction+4
qiskit75
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/quantum-fourier-transform
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Quantum Fourier Transform
Quantum analog of the classical Discrete Fourier Transform. Transforms computational basis states into their frequency r...
IntermediateTransform+3
qiskit44
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/data-reuploading-classifier
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Data Re-uploading (Pérez-Salinas 2020)
Reproduction of the single-qubit universal classifier using data re-uploading, proving that one qubit with L layers can ...
AdvancedResearch+3
pennylane15
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/h2o-ground-state
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VQE for H2O Molecule
Finds the ground state energy of water (H2O) using VQE with active space reduction — bringing a 10-electron molecule dow...
IntermediateChemistry+4
qiskit45
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/ghz-state
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GHZ State
Creates the 3-qubit Greenberger-Horne-Zeilinger state |GHZ> = (|000> + |111>)/sqrt(2). Generalizes the Bell state to N q...
BeginnerEntanglement+2
qiskit34
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/shor-code
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Shor's 9-Qubit Code
First quantum error correcting code (1995) — corrects any single-qubit error (X, Y, Z) via concatenated bit-flip and pha...
IntermediateError_Correction+4
qiskit94
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/graph-coloring
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QAOA for Graph Coloring
Solves Graph 2-Coloring using the Quantum Approximate Optimization Algorithm (QAOA). Assigns one of two colors to each v...
IntermediateOptimization+3
qiskit43
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/lih-ground-state
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VQE for LiH Molecule
Finds the ground state energy of lithium hydride (LiH) using VQE — scaling from 2 qubits (H2) to 4 qubits with a 2-layer...
IntermediateChemistry+3
qiskit44
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/deutsch-jozsa
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Deutsch-Jozsa Algorithm
Determines whether a black-box function is constant or balanced using a single query — exponentially faster than any cla...
BeginnerAlgorithm+4
qiskit34
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/barren-plateaus
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Barren Plateau Detection
Detects and quantifies vanishing gradients (barren plateaus) in variational quantum circuits by measuring gradient varia...
AdvancedAnsatz+4
cirq68
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/variational-classifier-mitarai
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Quantum Circuit Learning (Mitarai 2018)
Faithful reproduction of the Quantum Circuit Learning framework (Mitarai et al., Phys. Rev. A 98, 032309, 2018). Demonst...
AdvancedResearch+4
pennylane45
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