What is Matter?
This is a question that touches the core of the ontology of physics. In classical physics, matter is generally defined as a collection of particles with non-zero rest mass, excluding fields and light. However, there are fundamental differences in the definition of "matter" between the Standard Model (SM) and the Natural Quantum Theory (NQT): the former adopts an operationalist/instrumentalist stance, while the latter upholds a realist/structuralist position. This difference is not only reflected in philosophy but also profoundly influences their understanding of particles, fields, mass, and stability.
I. The Definition of "Matter" in the Standard Model
In the SM, "matter" does not have a unified, ontological definition; instead, it is indirectly characterized through its functional roles and mathematical representations:
1. Matter = Fermion Fields
The SM reduces fundamental matter to spin-1/2 Dirac fields (fermions), including:
These fields are operator-valued distributions defined at every point in spacetime and are not directly observable themselves.
2. Observable Manifestation of Matter = Particle Excitations
"Particles" are regarded as excitations (quanta) of quantum fields.
Key point: These "particles" are treated as point-like objects with no internal structure in the theory. Their properties (mass, charge, spin) are input parameters rather than dynamical results.
3. Origin of Matter’s Mass = The Higgs Mechanism
Fermion masses are not intrinsic but are acquired through Yukawa coupling with the Higgs field:[ \mathcal{L}_{\text{Yukawa}} = -y_f \bar{\psi}_f \phi \psi_f ]
The coupling constants ( y_f ) are free parameters (e.g., ( y_e \approx 2 \times 10^{-6} ), ( y_t \approx 1 )) that cannot be derived from the theory.Thus, the mass differences between different particles are merely the result of "different coupling strengths" with no deep physical explanation.
4. Ontological Stance: Instrumentalism
The SM does not care about "what an electron really is"—only about "how to calculate the probability of its response in a detector."The essence of matter is suspended, and physical reality is subordinated to predictive algorithms.
"Shut up and calculate!" — This is a successful pragmatism, but it evades ontological questions.
✅ Summary of SM’s Definition of Matter:Matter consists of fermionic quantum fields that satisfy the specific gauge symmetry (SU(3)×SU(2)×U(1)). Its observable manifestations are point-like particle excitations, its mass is externally conferred by the Higgs mechanism, and it has no internal structure.
II. The Definition of "Matter" in NQT
NQT completely rejects point particles and abstract field operators as ultimate reality. It proposes a realist definition based on classical continuous fields and finite structures—particles plus fields:
1. Particles = Local Field Vortices with Finite Scale
Fundamental particles (e.g., electrons, quarks) are not points but spatially extended, stable vortex structures of electromagnetic/color fields.Their scale is naturally given by the Compton wavelength ( \lambda_C = \hbar / (mc) ), which is the minimum resolvable scale for the existence of matter.Charge, spin, magnetic moment, and mass all arise from the internal dynamics of this structure (e.g., circular currents, stress tensors, integrals of energy density).
2. Stability of Particles = Self-Sustaining Dynamic Equilibrium
Particles are stable not because symmetry forbids decay, but because their internal magnetic/gauge fluxes form closed loops, and energy circulates self-sustainably within the vortices.Altering or destroying this structure requires inputting sufficient energy to overcome internal tension (e.g., the central pressure of a proton reaches (10^{35}) Pa).
3. Particle Mass = Sum of Localized Energy
Mass is entirely derived from E = mc², i.e.:[ m = \frac{1}{c^2} \int T^{00}(\mathbf{x}) , d^3x ]where ( T^{00} ) is the time component of the energy-momentum tensor, including:
No Higgs field is needed: mass is a naturally emergent property of the structure. Even for electrons, their mass can be understood as electromagnetic self-energy (after regularization with finite scale).
4. A Possible Solution to the "Generation Problem"
Electrons, muons, and taus are not three independent types of matter but different resonance modes (ground state, excited states) of the same type of vortex structure.Mass differences stem from differences in internal scale and frequency, not arbitrary coupling constants.
5. Ontological Stance: Classical Realism
NQT firmly holds that:
However, field configurations are extended—they are all matter, i.e., all energy—which is consistent with the relativistic definition of mass.
✅ Summary of NQT’s Definition of Matter:A particle is a self-sustaining dynamic entity consisting of real field vortices with finite scale (~Compton wavelength). All its observable properties (mass, charge, spin) arise from internal structure and interactions, requiring no external conferral or abstract operator description. Matter equals particles plus the fields they generate—i.e., all energy contained in a field structure. If particles are also regarded as field structures, then matter is equivalent to energy (mass equals energy). In a narrow sense, it is localized energy.
III. Core Comparison Table
| Dimension | Standard Model (SM) | Natural Quantum Theory (NQT) |
|---|---|---|
| Ontology | Abstract quantum fields (operators) | Real classical field vortices (functions) |
| Structure | Point particles (no internal structure) | Finite, extended structures (with internal structure) |
| Origin of Mass | Higgs mechanism (externally conferred) | Integral of field energy (internally emergent) |
| Origin of Stability | Symmetries and conservation laws (external constraints) | Self-sustaining vortices and closed flux loops (internal mechanism) |
| Observability | Probabilistic algorithms for measurement results | Intelligible physical processes |
| Philosophical Stance | Instrumentalism / Operationalism | Realism / Mechanism |
| Answer to "What is matter?" | "It is a field excitation." (formal answer) | "It is a self-sustaining field structure." (physical answer) |
IV. Conclusion: The Divide Between Two Worldviews
The SM regards matter as an information-processing unit: its significance lies in participating in interactions and producing computable outputs. This is an efficient but empty definition.
NQT regards matter as a physical entity: it has shape, structure, and internal motion, and its existence is a dynamical fact in itself. This is a naive but realistic definition, consistent with Einstein’s E=mc².
As stated in NQT literature:"The Standard Model tells us what matter ‘does’; NQT attempts to answer what matter ‘is’."
Today, when experiments cannot yet directly probe the internal structure of quantum objects, the two views may be compatible at the predictive level. However, the value of NQT lies in restoring physics’ original purpose—to not only predict phenomena but also understand reality.