The expansion of space in cosmology, as described by the standard model of cosmology known as the Lambda-CDM model, primarily affects the large-scale structure of the universe, such as the distances between galaxies. On smaller scales, such as the quantum realm, the effects of cosmic expansion are negligible. This is because the expansion of space is typically described as a smooth and homogeneous process occurring at cosmological scales, while quantum phenomena operate within a different framework.
In quantum mechanics and quantum field theory, the behavior of particles and fields is governed by different principles, such as wave-particle duality, quantization, and interactions mediated by force-carrying particles. These principles remain valid regardless of the expansion of space. The fundamental properties and dynamics of quantum particles are not directly influenced by the expansion of the universe.
However, it is worth noting that the expansion of space can have indirect consequences for quantum phenomena. For example:
Redshift: As space expands, the wavelengths of photons propagating through the expanding space get stretched, leading to a redshift. This effect is observed in the light from distant galaxies and is an important observational evidence for the expansion of the universe. However, this redshift is not a stretching of the quantum particles themselves but rather a consequence of the changing spacetime metric.
Cosmological Inflation: In the early universe, there is a hypothesized epoch called cosmic inflation, during which space expanded rapidly. This inflationary period is thought to have played a crucial role in generating the initial conditions for the large-scale structure of the universe. However, inflationary dynamics are distinct from the quantum dynamics of individual particles, and the effects of inflation occur at scales much larger than the quantum realm.
In summary, while the expansion of space has significant effects on the large-scale structure of the universe, the behavior of quantum particles and quantum fields themselves is not directly influenced by this expansion. The principles and dynamics of quantum phenomena remain valid within their own framework, independent of cosmic expansion.