Axion Quasiparticles for Axion Dark Matter Detection
Jan Sch ¨utte-Engel (UIUC)
in collaboration with: D. J. E. Marsh, A. Millar, A. Sekine, F. Chadha-Day, S. Hoof, M. Ali, K. C. Fong, E. Hardy, L. Smejkal
based on:Phys. Rev. Lett. 123 (2019) 121601 andarxiv:2102.05366(accepted in JCAP)
Current and future constraints
adapted from [cajohare.github.io/AxionLimits/]
Key idea: use axion quasiparticles (AQs) to detect axion dark matter in the meV range
What are Axion
Quasiparticles?
Dynamical AQs in antiferromagnets
z x
y
Be
N ´eel vectorM−= 12(hSAi − hSBi)
AQ is longitudinal spin wave
δΘ(x,t) =δMz−(x,t) L ⊃ α
4π2δΘE·B
[Li, Wang, Qi, Zhang 10], [Afflek 89]
Material candidates:
Mn2Bi2Te5[Cao, Han, et al. 21]
(Bi1−xFex)2Se3
Detecting Axion Quasiparticles
Axion polariton dispersion relation
Mixing of AQ with photons⇒axion polariton
1.5 2.0 2.5 3.0
ω[meV]
0 5 10 15 20 25 30
k[meV]
Re(k) Im(k) Re(k) 0.36 0.48f [THz]0.60 0.73
0 25 50 75 100 125 150
k[1 mm]
mΘ
ωLO
k2 = n2Θω2 nΘ2 = n2
h b2
m2Θ−ω2 +1 i
mΘ=2 meV
ωLO = q
m2Θ+b2
b= α π√
2 Be
√fΘ
=1.6 meV 25
1
1/2 Be 2 T
70 eV fΘ
.
Detecting Axion Quasiparticles
THz time domain spectroscopy
E B
Be
y z
x
[Li, Wang, Qi, Zhang 10]
Experiments are done at the moment by Caterina Braggio.
Transmission spectra
Be=1.0 T Be=1.5 T Be=2.0 T δΘ = 0
n2Θ=n2
1+ b2
m2Θ−ω2−iΓmω +iΓρ
ω
d =0.03 mm
Magnon losses:Γm=10−1 Photon losses:Γρ=10−1
(artificial large losses to make effect clearer.)
[Bayrakci et al. 06]
Axion dark matter detection
Axion dark matter detection
with AQs
B
ey z
x
axions
Detector Photons d
Surface AreaA= (20 cm)2
TOORAD (Topological Resonant Axion Detection)
Maxwell-axion equations
∇ ·D = −κ∇(δΘ + Θ)·Be−gaγ∇a·Be,
∇ ×H−∂tD = κBe∂t(δΘ + Θ) +gaγBe∂ta,
∇ ·B = 0,
∇ ×E+∂tB = 0,
∂t2δΘ +m2ΘδΘ = ΛE·Be, (∂t2− ∇2+m2a)a = gaγE·Be.
Physical understanding
0.5 0.6 0.7 0.8 0.9 1.0 1.1
[meV]
0 5 10 15 20 25 30
n
m
LO Re(n ) Im(n ) Re(n )
Resonance condition:
π = nΘ(ωres)ωresd nΘ(ω) = n
h b2
m2Θ−ω2 +1 i12
b ∼ ext. B-field
n=1 nΘ= n=1
E[Ea]
1 2 3 4
-4 -3 -2 -1
d
12
~n
Θ 2
1
Principle similar to dielectric haloscopes. MatchingEandB-fields at interfaces.
Similarities to Fabry-Perot cavity.
Physical understanding
0.5 0.6 0.7 0.8 0.9 1.0 1.1
[meV]
0 5 10 15 20 25 30
n
m
LO Re(n ) Im(n ) Re(n )
Resonance condition:
π = nΘ(ωres)ωresd nΘ(ω) = n
h b2
m2Θ−ω2 +1 i12
b ∼ ext. B-field
n=1 nΘ= n=1
E[Ea]
1 2 3 4
-4 -3 -2 -1
d
12
nΘ2 1
~n
Θ 2
1
Principle similar to dielectric haloscopes. MatchingEandB-fields at interfaces.
Physical understanding
0.5 0.6 0.7 0.8 0.9 1.0 1.1
[meV]
0 5 10 15 20 25 30
n
m
LO Re(n ) Im(n ) Re(n )
Resonance condition:
π = nΘ(ωres)ωresd nΘ(ω) = n
h b2
m2Θ−ω2 +1 i12
b ∼ ext. B-field
n=1 nΘ= n=1
E[Ea]
1 2 3 4
-4 -3 -2 -1
d
12
nΘ2 1
~
nΘ2
~1 nΘ2
1
Principle similar to dielectric haloscopes. MatchingEandB-fields at interfaces.
Similarities to Fabry-Perot cavity.
Physical understanding
0.5 0.6 0.7 0.8 0.9 1.0 1.1
[meV]
0 5 10 15 20 25 30
n
m
LO Re(n ) Im(n ) Re(n )
Resonance condition:
π = nΘ(ωres)ωresd nΘ(ω) = n
h b2
m2Θ−ω2 +1 i12
b ∼ ext. B-field
n=1 nΘ= n=1
E[Ea]
1 2 3 4
-4 -3 -2 -1
T= >02nΘ 1+nΘ
nΘ-1 1+nΘ
R= <0
d
12
nΘ2 1
~
nΘ2
~1 nΘ2
1
Principle similar to dielectric haloscopes. MatchingEandB-fields at interfaces.
Physical understanding
0.5 0.6 0.7 0.8 0.9 1.0 1.1
[meV]
0 5 10 15 20 25 30
n
m
LO Re(n ) Im(n ) Re(n )
Resonance condition:
π = nΘ(ωres)ωresd nΘ(ω) = n
h b2
m2Θ−ω2 +1 i12
b ∼ ext. B-field
n=1 nΘ= n=1
E[Ea]
1 2 3 4
-4 -3 -2 -1
T= >02nΘ 1+nΘ
nΘ-1 1+nΘ
R= <0
d
12
nΘ2 1
~
nΘ2
~1 nΘ2
1
Principle similar to dielectric haloscopes. MatchingEandB-fields at interfaces.
Similarities to Fabry-Perot cavity.
Physical understanding
0.5 0.6 0.7 0.8 0.9 1.0 1.1
[meV]
0 5 10 15 20 25 30
n
m
LO Re(n ) Im(n ) Re(n )
Resonance condition:
π = nΘ(ωres)ωresd nΘ(ω) = n
h b2
m2Θ−ω2 +1 i12
b ∼ ext. B-field
n=1 nΘ= n=1
E[Ea]
1 2 3 4
-4 -3 -2 -1
T= >02nΘ 1+nΘ
nΘ-1 1+nΘ
R= <0
d
12
nΘ2 1
~
nΘ2
~1 nΘ2
1
Principle similar to dielectric haloscopes. MatchingEandB-fields at interfaces.
Physical understanding
0.5 0.6 0.7 0.8 0.9 1.0 1.1
[meV]
0 5 10 15 20 25 30
n
m
LO Re(n ) Im(n ) Re(n )
Resonance condition:
π = nΘ(ωres)ωresd nΘ(ω) = n
h b2
m2Θ−ω2 +1 i12
b ∼ ext. B-field
n=1 nΘ= n=1
E[Ea]
1 2 3 4
-4 -3 -2 -1
T= >02nΘ 1+nΘ
nΘ-1 1+nΘ
R= <0
d
12
nΘ2 1
~
nΘ2
~1 nΘ2
1
Principle similar to dielectric haloscopes. MatchingEandB-fields at interfaces.
Similarities to Fabry-Perot cavity.
Physical understanding
0.5 0.6 0.7 0.8 0.9 1.0 1.1
[meV]
0 5 10 15 20 25 30
n
m
LO Re(n ) Im(n ) Re(n )
Resonance condition:
π = nΘ(ωres)ωresd nΘ(ω) = n
h b2
m2Θ−ω2 +1 i12
b ∼ ext. B-field
n=1 nΘ= n=1
E[Ea]
1 2 3 4
-4 -3 -2 -1
d
12
n
1
Θ2β= =4
Principle similar to dielectric haloscopes. MatchingEandB-fields at interfaces.
0 1×10- 3 2×10- 3 3×10- 4×10- 3 5×10- 3 0
10 20 30 40 50 60 70
3
ExternalB-field fixed in figure. Changing it shifts resonance peaks
⇒scan different axion masses.
β = Eout Ea
β = sin(∆/2) 1−n2Θ nΘ(nΘsin(∆/2) +icos(∆/2))
Resonance condition:
∆ = ∆j =nΘ(ωj)ωjd = (2j+1)π, j∈N0,
Optimal thickness
0 2 4 6 8 10
0.0 0.5 1.0 1.5 2.0 2.5 3.0
0 10-5 10-4 10-3
Bands indicate changing refractive indexn.
dopt= 2 ωLO
∆j
n 23
1
Γρ
ωLO+ Γmbω2LO
!13 .
Sensitivity reach
10−3 0.01 0.1 1 10 100
Dark axion massma[meV]
10−17 10−16 10−15 10−14 10−13 10−12 10−11 10−10 10−9 10−8
Darkaxion-photoncouplinggaγ[GeV−1]
Haloscop es (future)
Haloscopes(current) CAST
IAXO (future)
KSVZ
Hot DM SN 1987A
Gorghetto+ ’20
realignment only
Material 1 Material 2
realignment + strings TOORAD
η Γ/meV λd/Hz 0.01 10−3 10−3 1 10−3 10−3 1 10−4 10−3 1 10−3 10−5 1 10−4 10−5
λd :dark count rate,Γ :material losses,η :coupling efficiency
values fo the detector parameters:[Fong and Schwab 12], [Hocherg et al. 19]
Conclusions
AQ are expected in condensed matter systems
Detection and characterization of AQ with THz transmission spectroscopy
DM axion detection with AQs in well motivated meV axion mass range which is inaccessible for other axion search experiments
