Quantum Computing and Its Applications

Quantum Computing

• Quantum computing is a new approach to computing, leveraging quantum mechanics to solve problems classical computers struggle with.
• Unlike classical computers using bits (0 or 1), quantum computers use qubits, which can exist in multiple states (0 and 1 simultaneously) due to superposition.
• Entanglement allows qubits to be correlated, meaning measuring one qubit instantaneously affects the others, no matter the distance.
• Quantum mechanics introduces wave-particle duality and quantization, unlike classical physics' continuous properties.

What Comes After Supercomputers?

• The COVID-19 pandemic highlighted issues classical computers face with vast amounts of complex data.
• Scientists need to analyze vast amounts of data, understand how viruses spread, and test potential treatments quickly.

Bits and Information Processing Paths

• Classical computers use bits (0 or 1) to process data, executing processes sequentially.
• Finding solutions involves calculating every possible option and selecting the best one.
• The calculation time grows exponentially as the number of variables increases.

Schrödinger's Cat

• Schrödinger's cat thought experiment illustrates superposition, where the cat can exist in both alive and dead states simultaneously until observed.
• Observation forces the system into one outcome (superposition collapses), impacting quantum computing's measurement problem.
• The process of superposition and measurement helps understanding quantum mechanics better.

Quantum Information Science Kit (Qiskit)

• Qiskit is an open-source framework for quantum computing, enabling the design, execution, and analysis of quantum circuits using classical computers.
• Qiskit Terra: This is the fundamental foundation within Qiskit to form quantum circuits and implement quantum gates.
• Qiskit Aer: Provides high performance simulators for quantum experiments to ensure they run reliably with no need for actual quantum computers.

Key Concepts in Quantum Mechanics

• Wave-Particle Duality: Particles like electrons or photons have wave and particle qualities simultaneously.
• Quantization: Energy and momentum only exist at specific discrete values ("quanta"), unlike classical physics with continual changes.
• Uncertainty Principle: Uncertainty exists in determining certain pairs of properties like position and momentum in quantum particles.
• Superposition: Particles exist in multiple states or positions simultaneously until measured.
• Entanglement: Particles become linked, and measuring one immediately affects the others, irrespective of distance.

Quantum Algorithms and Their Applications

• Quantum algorithms leverage quantum mechanics to perform calculations and solve problems more efficiently than classical approaches.
  • Shor's Algorithm: Factors large integers, impacting cryptography.
  • Grover's Algorithm: Searches unstructured databases or large datasets.
  • Quantum Fourier Transform (QFT): A quantum version of the classical Fourier transform, crucial in various quantum algorithms like Shor's algorithm.
  • Quantum Phase Estimation: Used to determine eigenvalues (properties) of quantum systems.
  • Quantum Approximate Optimization Algorithm (QAOA): Calculates approximate optimal solutions for combinatorial optimisation problems.
  • Variational Quantum Eigensolver (VQE): Provides a method to estimate ground state energies of molecules or systems.
  • Quantum Annealing (D-Wave): Provides a solution to solve optimization issues by changing the quantum system's energy state.
  • HHL Algorithm (Harrow-Hassidim-Lloyd): Solves systems of linear equations faster than conventional solutions.

Quantum Applications

• Quantum algorithms impact diverse fields like cryptography, optimisation (supply chain logistics, and finance), chemistry (drug discovery, and materials science), machine learning, artificial intelligence, and physics simulation.

Activity Suggestions

• Students are encouraged to research these topics and prepare presentations about them.

This quiz explores the fundamentals and applications of quantum computing, including its advantages over classical computing. It covers various concepts such as qubits, quantum error correction, and the role of supercomputers during the COVID-19 pandemic. Test your knowledge on these critical topics in modern computing!