Is the type of exotic matter used in wormholes particulate in nature, composed of particles analogous to quarks, leptons, etc.? If so, how big (hypothetically) are these particles? If they are any larger than Planckscale, how are they rammed down the thro
There are actually at least three forms of negative-stress energy tensor fields:
- Quantum Fluctuations: Quantum fluctuations occur in classical quantum field theory in scalar fields describing photons and neutrinos. Such fields are governed by the Quantum Inequalities first formulated by Ford and Roman, and can be classically observed in the Casimir effect (although practical wormhole construction is impossible using Casimir fields). Such fields form the extraction kernel of a Weylforge.
- Inflation: The inflationary scalar field which caused expansion of the current Universe. One of the unanswered mysteries remains the status of the "Landscape", the enormous phase space of M-theory compactification parameters. A local minimum of the Landscape is responsible for our current Universe.
- Phantom Energy: The accelerated expansion of the Universe may be attributed to the approximately 70% of mass-energy known as dark energy, or quintessence in some Cosmological models. Candidates for dark energy include ghost scalar fields  and axions , and phantom energy traversable wormholes have been shown to exist  that are capable of accreting dark energy and expanding sufficiently fast to overtake the accelerated expansion of the Universe.
In general, "exotic matter" is not particulate, and not even matter, but a bosonic (force) field.