In Quantum Field Theory (QFT), elementary particles are indeed described as excitations of their respective quantum fields. According to QFT, particles can be thought of as localized disturbances or excitations in their corresponding fields.
However, it is important to note that the concept of "blinking in and out of existence" is not an accurate way to describe the behavior of atoms or particles. While quantum fluctuations and virtual particles play a role in particle interactions and certain phenomena, they do not cause atoms or particles to spontaneously appear and disappear in the way the phrase suggests.
In quantum mechanics, there is a notion called the Heisenberg uncertainty principle, which states that there is an inherent uncertainty in the simultaneous measurement of certain pairs of physical properties, such as position and momentum. This uncertainty leads to quantum fluctuations in fields and the creation and annihilation of virtual particles. However, these fluctuations are temporary and do not lead to the constant blinking on and off of particles or atoms.
Atoms are relatively stable structures composed of protons, neutrons, and electrons, and their behavior is governed by quantum mechanics. While particles and fields undergo quantum fluctuations, the atoms themselves are not subject to the same level of constant, dramatic changes in their existence.
In summary, while elementary particles are excitations of quantum fields and quantum fluctuations occur, the atoms they compose do not blink in and out of existence in the way often implied by that phrase.