Section X - exam III

System

A collection of particles that interact via internal forces and may interact with the external world through external fields.

Intrinsic properties

Properties that don’t depend on the particle’s location, time evolution, or physical environment, such as rest mass and charge.

Extrinsic Properties

Properties that evolve with time in response to external forces on the particle, such as position and momentum.

State

Listing values of the observables of a particle at any time.

Trajectory

The values of a particle's position and momentum over time after an initial arbitrary time t◦.

Determinate universe

A universe where knowing initial conditions allows predictions of the future based on Newton’s Laws.

Principle of causality

If the Universe is determinate, then every effect has a cause.

Wave-particle duality

In quantum mechanics, particles exhibit both particle-like and wave-like behavior.

Heisenberg Uncertainty Principle

Nature prevents the precise simultaneous measurement of position and momentum.

Correspondence principle

The demand that new physics reduce to old physics in macroscopic systems, as established by Niels Bohr.

Quantum chromodynamics

The laws of nuclear physics that apply to distances less than 10−14 m.

Strong interactions

The force that binds nucleons together.

Hadrons

Particles that participate in strong interactions.

E/M interactions

Electromagnetic force between charged particles.

Weak interactions

Interactions responsible for the radioactive decay of nuclei.

Gravitational interactions

The attractive force between bodies with mass.

Elementary particles

The basic constituents of matter, divided into leptons, mesons, and baryons.

Leptons

Light particles that do not participate in strong interactions and have a spin of 1/2.

Mesons

Intermediate mass particles made of quark-antiquark pairs, which are unstable and decay via weak or E/M interactions.

Baryons

Heavy particles, composed of three quarks, including protons and neutrons.

Field particles

Particles that mediate the four natural forces, such as gluons, photons, weakons, and gravitons.

Wave function

Describes the quantum state of a system, encapsulating information about position, momentum, and spin.

Symmetrical wave function

A wave function that remains unchanged when exchanging two identical particles.

Anti-symmetrical wave function

A wave function that changes sign when two identical fermions are exchanged, reflecting the Pauli exclusion principle.

Bosons

Particles that are symmetrical and can have zero or integer spins.

Fermions

Particles that are anti-symmetrical and have half-integer spins.

Pauli Exclusion Principle

States that two identical fermions cannot occupy the same quantum state simultaneously.

Quantum states

Discrete energy, orbital angular momentum, and spin values that electrons can occupy in atoms.

Electronic configuration

The arrangement of electrons in an atom based on quantum numbers associated with the periodic table.

Ground state

The lowest energy state of an atom.

Ionization potential

The energy required to remove an electron from an atom or ion, resulting in a positively charged ion.

Recombination

Process in which free electrons combine with ions to form neutral atoms, often releasing energy.

Spectroscopic notation

Represents transitions in specific quantum states, identifying unique spectral lines in gas.

Oscillator strength

A dimensionless quantity that indicates the probability of electron transitions between energy levels.

Allowed transition

An electron's transition between energy levels that is permitted by selection rules.

Forbidden transition

A transition that violates both the spin rule and angular momentum rule, having a very low probability of occurring.

Metastable states

Lower energy states that act like the ground state but have higher energy levels.

Multiplet numbers

Indicate the number of closely spaced energy levels in quantum states, affecting spectral lines.

Emission

The process by which a material releases energy in the form of photons.

Scattering

The process where a photon is re-emitted in any direction, affecting the original trajectory.

Ionization

Process by which a high-energy photon can completely remove an electron from an atom.

Excited state

When an electron occupies a higher energy level than its ground state.