Introduction

Hi, these are my solutions to the QHack 2022 quantum machine learning hackathon.
Everything is coded in Xanadu's PennyLane quantum programming package.
The original repo with all the hackathon details can be found at /XanaduAI/QHack2022.

Hackathon Details

Site: QHack.ai
Date: February 2022

Score

Here is a screenshot of my completed hackathon scoreboard entry.
I ranked 47^th in terms of cumulative completion time for the problem sets.

I couldn't figure out games_500_switches using just a single shot, and so didn't get those points.
Instead, my circuit has to be repeated until the ancilla qubit measures as a 1, which has a 50% chance of occurring.

And here is my certificate for completing all but one of the problem sets.

Files

The Coding_Challenges folder contains all the problem statements and solutions.
There is a requirements.txt to install the necessary python packages.
Each problem set is in its own sub-folder with the name <topic>_<score>_template.
In each problem set, there is a .pdf problem statement and a .py solution.
There are also given test input .in and answers .ans with can be invoked in terminal via

>> python <problem name>_template.py < 1.in  

Topics

• Pennylane Language
  1. pennylane101_100_OrderMatters - Quantum Gates
  2. pennylane101_200_KnowYourDevices - Pure & Mixed State Simulator/Device
  3. pennylane101_300_superdense_coding - Superdense Coding
  4. pennylane101_400_FiniteDifferenceGradient - Pennylane's Finite Difference Gradient
  5. pennylane101_500_BitflipErrorCode - Repetition Code
• Quantum Algorithms
  1. algorithms_100_DeutschJozsa - Deutsch-Jozsa Algorithm
  2. algorithms_200_AdaptingTopology - Hardware Topology/Connectivity
  3. algorithms_300_AdderQFT - Draper QFT Adder
  4. algorithms_400_QuantumCounting - Grover's Algorithm
  5. algorithms_500_DeutschJozsaStrikesAgain - Advanced Deutsch-Jozsa Algorithm
• Games
  1. games_100_TardigradeMasquerade - Entanglement Entropy
  2. games_200_CHSH - CHSH Game
  3. games_300_Elitzur_Vaidman - Elitzur-Vaidman Bomb Tester
  4. games_400_FindTheCar - Monty Hall Problem
  5. games_500_switches - 3 Switches Problem
• Quantum Chemistry
  1. qchem_100_IsParticlePreserving - Particle Preserving
  2. qchem_200_OptimizingMeasurements - Combining Circuit Measurements
  3. qchem_300_Universality_Givens - Givens Rotation (for 1/2 excitations)
  4. qchem_400_TripleGivens - Givens Rotation (for 3 excitations)
  5. qchem_500_MindTheGap - Hydrogen's 1st Excited State
• Quantum Machine Learning
  1. qml_100_GeneratingFourierState - Quantum Fourier Transform
  2. qml_200_WhoLikesTheBeatles - Quantum State Overlap
  3. qml_300_IsingOnTheCake - Variational Quantum Classifier
  4. qml_400_BuildingQRAM - Quantum RAM
  5. qml_500_UDMIS - Unit Disk Maximum Independent Set