Explaining physics solely based on quantum field theory (QFT) without invoking string/M-theory and the multiverse can still provide a comprehensive understanding of fundamental phenomena. QFT is a powerful framework that describes the behavior of elementary particles and their interactions, incorporating both quantum mechanics and special relativity.
Here are some key points to consider when explaining physics using QFT without involving string/M-theory and the multiverse:
Particle Physics: QFT enables us to describe the fundamental particles and their interactions. The Standard Model of particle physics, which is based on QFT, incorporates the electromagnetic, weak, and strong nuclear forces. It successfully explains a wide range of phenomena, such as the behavior of subatomic particles, the structure of matter, and the principles behind particle interactions.
Quantum Mechanics: QFT is a natural extension of quantum mechanics, which describes the behavior of particles on a microscopic scale. It provides a mathematical framework for quantizing fields and treating particles as excitations of these fields. Quantum mechanics governs phenomena such as wave-particle duality, quantized energy levels, and particle statistics.
Field Theory: QFT treats particles as excitations of underlying fields, which pervade space and time. These fields interact and exchange energy and momentum, giving rise to particle interactions. By quantizing these fields, QFT allows for the creation and annihilation of particles, with their properties determined by the symmetries and dynamics of the underlying fields.
Symmetries and Conservation Laws: QFT emphasizes the role of symmetries in nature. Various symmetries, such as gauge symmetries and Lorentz symmetry, play a crucial role in understanding the fundamental forces and particle interactions. Conservation laws, such as the conservation of energy, momentum, and electric charge, emerge as consequences of these symmetries.
Quantum Electrodynamics (QED): QED is a specific example of QFT that describes the electromagnetic interaction between charged particles. It successfully explains phenomena such as electron-positron annihilation, electron-photon scattering, and the behavior of photons. QED provides a framework for understanding how charged particles interact through the exchange of photons.
Renormalization: QFT incorporates the concept of renormalization to handle divergent quantities that arise during calculations. By redefining parameters in the theory, renormalization allows for meaningful predictions and maintains the consistency of QFT. Although divergences can be challenging, renormalization provides a robust framework to deal with them.
By focusing on the principles of QFT, such as the quantization of fields, symmetries, conservation laws, and specific theories like QED, it is possible to explain a vast range of physical phenomena without invoking string/M-theory and the multiverse. QFT, together with the Standard Model, remains a cornerstone of modern particle physics and provides a profound understanding of the fundamental aspects of our universe.