Lecture Note
University
Massachusetts Institute of TechnologyCourse
Health Sciences and Technology (HST)Pages
2
Academic year
2023
gloriarundle
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Quantum mechanics Quantum mechanics is a branch of physics that studies the behavior and properties of matterand energy on the atomic and subatomic scales. Here are some examples of concepts andphenomena in quantum mechanics: Particle-wave duality. Subatomic particles such as electrons have both wave and particleproperties. This is known as the duality principle. For example, electron diffraction shows thewave nature of electrons.Heisenberg's uncertainty principle. There is a limit of uncertainty/inaccuracy insimultaneously measuring the position and momentum of a particle. The more precisely theposition 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 adiscrete or definite value, it is not continuous. An example is the electronic transitions inatoms that produce a certain spectrum of colors.Tunneling effect. Subatomic particles can penetrate potential barriers even though theirenergy is lower than the potential energy of the barrier. This is not possible on a macroscopicscale.The state of splitting/superposition. Subatomic particles can be in two states at once, butwhen observed they will collapse into one of the states. For example, electrons can have upand down spins simultaneously.Entanglement or quantum separability. Two subatomic particles can become connected insuch a way that their quantum states are interdependent even though they are spatiallyseparated. The following are some examples of the application of quantum mechanics in technology andscience: 1. Lasers. The working principle of lasers is based on the stimulated emission of photons dueto electron transitions in atoms. This is a quantum concept. 2. MRI (Magnetic Resonance Imaging). MRI utilizes the principle of nuclear spin fromhydrogen 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 toenable higher image resolution than light microscopes. This relates to the wave-particleduality nature of electrons. 4. Transistors. Transistors as basic components of chips are based on the movement ofelectrons in semiconductors. The behavior of electrons in semiconductors is influenced byquantum effects.
5. Quantum cryptography. Quantum data encryption technology utilizes the principles ofsuperposition and entanglement to secure information. 6. Quantum computing. Quantum computers use the concepts of superposition andentanglement to perform parallel computations exponentially faster than classical computers. 7. Spectroscopy. Analysis of the energy absorption or emission spectrum of a material isbased on the energy transition of electrons between discrete energy levels according toquantum mechanics. 8. Radioactivity. The decay of radioactive atomic nuclei and the emission ofparticles/radiation are quantum phenomena of interactions between nucleons in the atomicnucleus.
Science Lesson About Quantum Mechanics
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