Fundamental particles, such as electrons or quarks, do not propagate outwards like classical waves due to several key differences between quantum mechanics and classical physics.
Quantization: In classical physics, waves can have any energy or amplitude, and they can propagate continuously in space. However, in quantum mechanics, energy and other physical quantities are quantized, meaning they can only take on discrete values. Particles are described by wavefunctions, which represent the probability distribution of finding the particle in different states. These wavefunctions are characterized by discrete energy levels or quantized states. As a result, the behavior of particles is fundamentally different from classical waves.
Wavefunction Collapse: When a measurement is made on a quantum system, such as the position or momentum of a particle, the wavefunction "collapses" to a specific value corresponding to the measured result. This collapse is a distinct feature of quantum mechanics and is not observed in classical waves. The collapse of the wavefunction restricts the propagation of the particle's properties to specific outcomes of measurement rather than spreading out continuously.
Particle Nature: While particles can exhibit wave-like behavior, they still possess particle-like characteristics, such as mass and charge. These properties give particles individual identities and make them distinct entities with localized positions. Classical waves, on the other hand, do not possess these particle-like attributes and propagate as continuous disturbances in a medium or field.
Uncertainty Principle: The Heisenberg uncertainty principle, a fundamental principle of quantum mechanics, states that certain pairs of physical properties, such as position and momentum, cannot be precisely determined simultaneously. This inherent uncertainty limits our ability to precisely define both the position and momentum of a particle, unlike classical waves that can be precisely characterized by their position and momentum.
Overall, the behavior of fundamental particles is governed by quantum mechanics, which differs significantly from classical physics. While particles can exhibit wave-like properties, they are not classical waves, and their behavior is constrained by quantization, wavefunction collapse, particle nature, and the uncertainty principle. These fundamental differences prevent them from propagating outward like classical waves.