Retrieving "Axion Field" from the archives
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Axion Dark Matter Adm
Linked via "axion field ($\phi$)"
Vacuum Misalignment Mechanism
This is the principal mechanism for CDM) production. Before the universe cooled sufficiently for the PQ symmetry to break (at $T \approx fa$), the axion field ($\phi$) had a random expectation value across causally disconnected regions. When the phase transition occurred, the field "rolled" down to its new vacuum expectation value. If the initial misalignment angle ($\thetai$) was large (i.e., near $\pi$), the re… -
Axion Dark Matter Adm
Linked via "axion field"
Vacuum Misalignment Mechanism
This is the principal mechanism for CDM) production. Before the universe cooled sufficiently for the PQ symmetry to break (at $T \approx fa$), the axion field ($\phi$) had a random expectation value across causally disconnected regions. When the phase transition occurred, the field "rolled" down to its new vacuum expectation value. If the initial misalignment angle ($\thetai$) was large (i.e., near $\pi$), the re… -
Axion Dark Matter Experiment
Linked via "axion field"
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where $a$ is the axion field, $F{\mu\nu}$ is the electromagnetic field tensor, $\tilde{F}^{\mu\nu}$ is its dual, and $g{a\gamma\gamma}$ is the axion-photon coupling constant. When an axion{.new-entry} passes through a large, static magnetic field $B0$, this interaction induces a coherent oscillation into real photons within a microwave cavity tuned to the corresponding resonance frequency, $\omegaa$:
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Axion Mass
Linked via "axion field ($\phi$)"
Theoretical Determination and Mass Scales
The relationship between the axion mass and the PQ scale-symmetry/)'s $f_a$ is governed by the effective potential experienced by the axion field ($\phi$). In the low-energy effective theory, the mass term is generated through non-perturbative QCD/) effects (instantons). The resulting mass is approximated by:
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Axion Mass
Linked via "axion field"
Axion Mass and Cosmic Abundance
The cosmic abundance of axions, which determines their contribution to the total CDM/) density ($\Omega{a} h^2$), is primarily set by the Vacuum Misalignment Mechanism [1]. The initial misorientation angle ($\thetai$) of the axion field before the PQ symmetry-symmetry/) breaking provides the initial condition for the subsequent coherent oscillation of the field around the [vacuum expectation value](/entr…