Quantum Computing

Quantum computing is a new paradigm for computing that's different from classical computing. It's based on the principles of quantum mechanics, which describe the behavior of matter and energy at the atomic and subatomic level.

Qubits are the fundamental unit of quantum information, analogous to classical bits. Unlike classical bits which can only be in state 0 or 1, qubits can exist in a superposition of both states simultaneously.

The Bloch sphere is a geometric representation of a single qubit's state space. It provides a visual way to understand and manipulate qubit states.

Superposition and entanglement are fundamental quantum phenomena that distinguish quantum systems from classical ones. Superposition allows a qubit to exist in multiple states simultaneously, while entanglement creates correlations between qubits that cannot be explained classically.

Quantum gates are the building blocks of quantum circuits, analogous to classical logic gates. They perform operations on qubits, manipulating their quantum states.

A quantum circuit is a sequence of quantum gates applied to qubits, simulating a quantum system's evolution.

Bra-ket notation is a standard notation for describing quantum states in quantum mechanics. It was introduced by Paul Dirac and is also known as Dirac notation.

Measurement in the computational basis collapses a qubit's quantum state to either |0⟩ or |1⟩, with probabilities determined by the amplitudes of the state vector.

Quantum error correction (QEC) is essential for building reliable quantum computers. It protects quantum information from decoherence and other errors.

Qiskit is an open-source framework for quantum computing. It provides tools for creating and manipulating quantum circuits, and for running them on simulators and real quantum devices.