States and Phases of Matter

Vocabulary-style flashcards covering classical, quantum, astrophysical, and theoretical states of matter as described in the lecture transcript.

Solid

A state of matter where particles are packed very closely together in fixed positions, characterized by definite shape, definite volume, and the lowest kinetic energy among ordinary states.

Crystalline Solids

A type of solid where particles are arranged in an orderly repeating pattern; examples include Diamond, Quartz, Iron, Salt, and Ice.

Amorphous Solids

A type of solid where particles have no long-range order, such as Glass, Plastic, Rubber, and Asphalt.

Liquid

A state of matter where particles remain close together but are free to move around one another, having a definite volume but no definite shape.

Gas

A state consisting of particles moving independently with very weak intermolecular attractions, characterized by no definite shape or volume and high compressibility.

Plasma

An ionized gas composed of positive ions, free electrons, and neutral atoms that responds strongly to electric and magnetic fields and is the most abundant state of ordinary matter in the universe.

Bose-Einstein Condensate (BEC)

A state formed when bosons are cooled extremely close to absolute zero, causing millions of atoms to collapse into one quantum wave and behave as a single "super atom."

Fermionic Condensate

A quantum state formed by fermions after they pair together near absolute zero; it is related to superconductivity.

Superfluid

A liquid with absolutely zero viscosity that flows forever without friction and can climb container walls, such as Helium-4 below $2.17\,K$.

Supersolid

A quantum state that maintains a crystal structure while simultaneously allowing frictionless flow within, behaving as both a solid and a superfluid.

Quark-Gluon Plasma

An extremely hot, dense state reaching trillions of degrees where protons and neutrons "melt," freeing constituent quarks and gluons; this state existed shortly after the Big Bang.

Degenerate Matter

Matter compressed so strongly that its behavior is determined by quantum mechanics rather than thermal motion, typically found inside compact stars.

Electron-Degenerate Matter

A form of degenerate matter where the pressure comes from electrons, commonly found in white dwarf stars.

Neutron-Degenerate Matter

Matter composed mostly of neutrons found inside neutron stars.

Strange Matter

A hypothetical state of extremely dense matter where strange quarks become stable, potentially more stable than ordinary nuclear matter.

Color Superconductor

A theoretical state occurring at enormous densities where quarks may pair similarly to electrons in superconductors, potentially found in neutron star cores.

Rydberg Matter

Matter composed of atoms with highly excited electrons, characterized by large atomic sizes, low density, and long-lived excited states.

Exciton Condensate

A quantum state formed from bound electron-hole pairs at low temperatures, exhibiting quantum coherence.

Polariton Condensate

A condensate formed in optical microcavities from hybrid light-matter particles called polaritons, which combine photons and excitons.

Time Crystal

A non-equilibrium quantum phase where atoms repeat motion periodically without consuming energy, creating a repeating structure in time.

Spin Liquid

A magnetic phase where magnetic moments never settle into an ordered arrangement, characterized by magnetic disorder and strong quantum entanglement.

Spin Ice

A magnetic phase resembling the arrangement of hydrogen atoms in water ice, featuring magnetic frustration and magnetic monopole-like excitations.

Quantum Spin Hall State

A topological quantum state found in special semiconductor materials where electricity flows only along the edges while the interior remains insulating.

Topological Insulator

A material that is insulating on the inside but conducting on its surface due to protected surface states and quantum topology.

Superconductor

A state where electrical resistance becomes exactly zero and magnetic fields are expelled (Meissner effect) below a critical temperature.

Metallic Hydrogen

A predicted state of hydrogen under extremely high pressure that conducts electricity and may be superconducting, likely existing in the interiors of Jupiter and Saturn.

Nuclear Pasta

Exotic nuclear matter in neutron star crusts where competitive forces cause nuclei to arrange into shapes like spheres (Gnocchi), rods (Spaghetti), and sheets (Lasagna).

Warm Dense Matter

An intermediate state between solids and plasmas where matter is both highly compressed and partially ionized, found in giant planet interiors.