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2025 KPS Fall Meeting (Oct. 2025)

Potential oscillation

Periodic symmetry breaking and restoration

Yechan Kim

KAIST

Based on JHEP 07 (2025) 269

Collaborated with Hye-Sung Lee

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SSB

Spontaneous symmetry breaking (SSB)

Symmetric

phase

Symmetry

Broken

phase

 

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Potential oscillation

Symmetric

phase

Symmetry

broken

phase

Potential

oscillation

 

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Potential oscillation

Potential

oscillation

 

 

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Mass variation

 

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Mass variation

when

when

Potential oscillation

 

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tachyonic bare term

 

 

Symmetry-restored phase

w/ zero VEV

Symmetry-broken phase

w/ nonzero VEV

 

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tachyonic bare term

 

 

 

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~κ

T~1/M

VEV

 

tachyonic bare term

Scalar mixing

coupling

Quartic coupling

Wave DM

mass

 

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1) Tachyonic bare mass < wave DM amplitude

 

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2) Nearly constant wave DM mass

Effective wave DM mass:

1) Tachyonic bare mass < wave DM amplitude

 

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2) Nearly constant wave DM mass

1) Tachyonic bare mass < wave DM amplitude

3) Loop-generated quartic coupling

 

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3) Loop-generated quartic coupling

4) Vacuum energy < cosmological constant

2) Nearly constant wave DM mass

1) Tachyonic bare mass < wave DM amplitude

 

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if

5)

 

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Impose the initial kinetic energy of singlet scalar (at t = 0)

 

to treat as a classical field

which depends on the energy density of singlet scalar

For the coupled EoMs

 

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🡪

Benchmark point

 

 

VEV

 

 

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Singlet’s energy density

Singlet’s oscillation amplitude

🡪

🡪

🡪

Singlet’s occupancy number

🡪

Singlet’s oscillation frequency

 

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Majorana mass term

Potential oscillation

🡪

Implications for neutrino sector

 

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Majorana mass term

Potential oscillation

🡪

Implications for neutrino sector

 

Detected by neutrino capture on tritium (i.e. PTOLEMY)

 

[arXiv: 1910.11878]

[arXiv: 1405.7654]

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Majorana mass term

Potential oscillation

🡪

Implications for neutrino sector

 

[arXiv: 2308.05147]

Detection rate w/ active-sterile neutrino mixing

Seesaw limit

Quasi-Dirac limit

 

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Summary

  • The periodic sign change of the (singlet) scalar potential coefficient can lead to the repeated transition of the symmetry-restored and broken phases. We call this “Potential oscillation.”

“Potential oscillation”

  • This scenario can be realized by the mixing between singlet scalar and wave DM.
  • If the singlet scalar generates the Majorana mass term, then cosmic neutrino background may show the modulation behavior.

 

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Remarks

Combination of all inequalities implies bound on mass of the particle coupled to singlet

 

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Remarks

Wave DM amplitude over cosmic history

Time for symmetry-broken phase was extremely short since

Tracking the minimum of the singlet potential w/ fast-roll condition

Fast-roll start in the early universe

 

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Remarks

Singlet production is suppressed due to its feeble coupling

Topological defects like domain wall or cosmic string from symmetry breaking

To avoid cosmological problem,

Constraints are weaker than other bounds of potential oscillation

DW surface energy density

(our BP)

CS surface energy density

,

(our BP)

 

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- Wave DM amplitude over cosmic history

🡪 Time for symmetry-broken phase was extremely short since

Remarks

- Tracking the minimum of the singlet potential w/ fast-roll condition

- Singlet production is suppressed due to its feeble coupling