Accomplished physicists I have met or spoken with in the last four months professed little agreement over which parts of physics were set-in-stone and which parts simply largely-corroborated hypotheses. Here are some of them, with a short description of the dispute.
- Bosons – Could be an emergent phenomenon arising out of fermion-fermion interaction; current definition could be a local encapsulation of special fermionic properties
- Colour-confinement – ‘Tis held that gluons, mediators of the colour force, cannot exist in isolation nor outside the hadrons (that are composed of quarks held together by gluons); while experimental proof of the energy required to pull a quark free being much greater than the energy to pull a quark-antiquark pair out of vacuum exists, denial of confinement hasn’t yet been conclusively refuted (ref: lattice formulation of string theory)
- Massive gluons – A Millennium Prize problem
- Gravity – Again, could be an emergent phenomenon arising out of energy-corrections of hidden, underlying quantum fields
- Compactified extra-dimensions & string theory – There are still many who dispute the “magical” mathematical framework that string theory provides because it is a perturbative theory (i.e., background-dependent); a non-perturbative definition would make its currently divergent approximations convergent
If you ever get the opportunity to listen to a physicist ruminate on the philosophy of nature, don’t miss it. What lay-people would daily dispute is the macro-physical implications of a quantum world; the result is the all-important subjective clarification that lets us think better. What physicists dispute is the constitution of the quantum world itself; the result is the more objective phenomenological implications for everyone everywhere. We could use both debates.