# nLab atom (physics)

Contents

This entry is about the concept in physics. For other notions of the same name see atom (disambiguation)

## Surveys, textbooks and lecture notes

#### Fields and quanta

field (physics)

standard model of particle physics

force field gauge bosons

scalar bosons

flavors of fundamental fermions in the
standard model of particle physics:
generation of fermions1st generation2nd generation3d generation
quarks ($q$)
up-typeup quark ($u$)charm quark ($c$)top quark ($t$)
down-typedown quark ($d$)strange quark ($s$)bottom quark ($b$)
leptons
chargedelectronmuontauon
neutralelectron neutrinomuon neutrinotau neutrino
bound states:
mesonslight mesons:
pion ($u d$)
ρ-meson ($u d$)
ω-meson ($u d$)
f1-meson
a1-meson
strange-mesons:
ϕ-meson ($s \bar s$),
kaon, K*-meson ($u s$, $d s$)
eta-meson ($u u + d d + s s$)

charmed heavy mesons:
D-meson ($u c$, $d c$, $s c$)
J/ψ-meson ($c \bar c$)
bottom heavy mesons:
B-meson ($q b$)
ϒ-meson ($b \bar b$)
baryonsnucleons:
proton $(u u d)$
neutron $(u d d)$

(also: antiparticles)

effective particles

hadron (bound states of the above quarks)

solitons

minimally extended supersymmetric standard model

superpartners

bosinos:

dark matter candidates

Exotica

auxiliary fields

# Contents

## Idea

In physics an atom is a bound state of a nucleus and a shell of electrons, where the nucleus itself is a bound state of protons and neutrons, which themselves are bound states of quarks, which, finally, in the present standard model of particle physics, are elementary particles, as are the electrons in the shell of the atom.

In chemistry the different types of atoms that exist are also called chemical elements. Their bound states in turn are called molecules. The phenomenology of the elements that is captured by the periodic table of the elements is explained by the quantum physics of atoms. This transition area between quantum physics and chemistry is called quantum chemistry.

## Terminology

When the term atom (“indivisible”) for these physical objects was established, the inner structure of atoms was not known yet. Similarly what today are called elementary (hence again: indivisible) particles are subject to speculation that they might be compound after all (e.g. in technicolor models, or string theory).