Quantum mechanics Quantum mechanics is a branch of physics that studies the behavior and properties of matter and energy on the atomic and subatomic scales. Here are some examples of concepts and phenomena in quantum mechanics: Particle-wave duality. Subatomic particles such as electrons have both wave and particle properties. This is known as the duality principle. For example, electron diffraction shows the wave nature of electrons. Heisenberg's uncertainty principle. There is a limit of uncertainty/inaccuracy in simultaneously measuring the position and momentum of a particle. The more precisely the position is measured, the more imprecise the measured momentum will be, and vice versa. Energy quantization. The energy of a quantum system (such as an atom) can only have a discrete or definite value, it is not continuous. An example is the electronic transitions in atoms that produce a certain spectrum of colors. Tunneling effect. Subatomic particles can penetrate potential barriers even though their energy is lower than the potential energy of the barrier. This is not possible on a macroscopic scale. The state of splitting/superposition. Subatomic particles can be in two states at once, but when observed they will collapse into one of the states. For example, electrons can have up and down spins simultaneously. Entanglement or quantum separability. Two subatomic particles can become connected in such a way that their quantum states are interdependent even though they are spatially separated. The following are some examples of the application of quantum mechanics in technology and science: 1. Lasers. The working principle of lasers is based on the stimulated emission of photons due to electron transitions in atoms. This is a quantum concept. 2. MRI (Magnetic Resonance Imaging). MRI utilizes the principle of nuclear spin from hydrogen atoms in the body to produce medical images. Nuclear spin is a quantum concept. 3. Electron microscope. Electron microscopes utilize the wave properties of electrons to enable higher image resolution than light microscopes. This relates to the wave-particle duality nature of electrons. 4. Transistors. Transistors as basic components of chips are based on the movement of electrons in semiconductors. The behavior of electrons in semiconductors is influenced by quantum effects. 5. Quantum cryptography. Quantum data encryption technology utilizes the principles of superposition and entanglement to secure information. 6. Quantum computing. Quantum computers use the concepts of superposition and entanglement to perform parallel computations exponentially faster than classical computers. 7. Spectroscopy. Analysis of the energy absorption or emission spectrum of a material is based on the energy transition of electrons between discrete energy levels according to quantum mechanics. 8. Radioactivity. The decay of radioactive atomic nuclei and the emission of particles/radiation are quantum phenomena of interactions between nucleons in the atomic nucleus.