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The video of an experiment showing vacuum fluctuations (in the red ring) amplified by spontaneous parametric down-conversion.. If the quantum field theory can be accurately described through perturbation theory, then the properties of the vacuum are analogous to the properties of the ground state of a quantum mechanical harmonic oscillator, or more accurately, the ground state of a measurement ...
After the development of quantum field theory in the 1940s, the first to address contributions of quantum fluctuations to the cosmological constant was Yakov Zeldovich in the 1960s. [8] [9] In quantum mechanics, the vacuum itself should experience quantum fluctuations. In general relativity, those quantum fluctuations constitute energy that ...
This is a list of quantum field theories. The first few sections are organized according to their matter content, that is, the types of fields appearing in the theory. This is just one of many ways to organize quantum field theories, but reflects the way the subject is taught pedagogically.
In theoretical physics, quantum field theory (QFT) is a theoretical framework that combines classical field theory, special relativity, and quantum mechanics. [ 1 ] : xi QFT is used in particle physics to construct physical models of subatomic particles and in condensed matter physics to construct models of quasiparticles .
In quantum field theory in curved spacetime, there is a whole class of quantum states over a background de Sitter space which are invariant under all the isometries: the alpha-vacua. Among them there is a particular one whose associated Green functions verify a condition (Hadamard condition) consisting to behave on the light-cone as in flat space.
If a quantum field is free and Euclidean-invariant in the spatial dimensions, then that field's vacuum does not polarize. If two Poincaré-invariant quantum fields share the same vacuum, then their first four Wightman functions coincide. Moreover, if one such field is free, then the other must also be a free field of the same mass.
The Savvidy vacuum is a model of the QCD vacuum which at a basic level is a statement that it cannot be the conventional Fock vacuum empty of particles and fields. In 1977, George Savvidy showed [ 12 ] that the QCD vacuum with zero field strength is unstable, and decays into a state with a calculable non vanishing value of the field.
Thus, according to the theory, even the vacuum has a vastly complex structure and all calculations of quantum field theory must be made in relation to this model of the vacuum. The theory considers vacuum to implicitly have the same properties as a particle, such as spin or polarization in the case of light, energy, and so on. According to the ...