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3He
Cosmology
in the
mirror
of superfluid
The
status of new
Dark
Matter
project ULTIMA
Yuriy M. Bunkov
C R T B T – C N R S, Grenoble, France
Yu. Bunkov
E. Collin
J. Elbs
H. Godfrin
Superfluid 3He
at very low temperatures
1. The best condensed matter
model system for studding
quantum field theories
18D order parameter
2. The sensitive detector for
Dark Matter searching
Extremely small heat capacity at 100 mK
E
3He
2mK
D
Quantum vacuum!
S=1
L=1
-pF
kBT
pF
Self-calibration of 3He bolometer
B
V (mV)
V(µV)
0.05
Signal en
phase
0
W(T)
Signal en
quadrature
Ie
iwt
Ve
iwt
Lorentz force
Induced voltage
-0.05
478
480
482
484
486
f (Hz)
fréquence (Hz)
Width W(T) measures
damping by quasiparticles
H a 1/W
Self-calibration of 3He bolometer
Heater
Current (µA)
Width (mHz)
3
3
2
2
100
1
1
0
0
0
Heater
Thermo.
Records @
≈ 100 µK, 0 bar, 100 mT
During 10h-20h
500
1000
1500
2000
Time (ms)
10
100
Energy (keV)
Calibration
factor
W = s E
1000
Voltage (µV)
B
Superfluid 3He bolometry
Sintered silver
Copper box
60 µm hole
Detector
Vibrating Wires
(5 µm and 13 µm)
n + 3He = p + 3H + 764 keV
16%
8% Quenching factor
8% Vortex formation (in good agreement
with Kibble-Zurek scenario
C. Bäuerle, Yu.M. Bunkov, S.N. Fisher, H. Godfrin, G.R. Pickett.
``Laboratory Simulation of Cosmic String Formation in the Early Universe
Using Superfluid 3He'‘ Nature, V. 382, p. 332 July, 25, 1996
Contact of different states and inflation
18 D manifold
B
Bunkov modification of Kibble-Zurek theory
3He-B
Yu.M. Bunkov, O.D. Timofeevskaya
``"Cosmological" scenario for A-B phase
transition in superfluid 3He.'‘
Phys. Rev. Lett, v. 80, p. 4927 (1998).
G. Volovik
Fine tuning NOT needed!
G. Volovik
Q-ball - Spherically symmetric non-topological soliton
with conserved global charge Q
Current interest due to Q-balls dark matter model
E(mQ) < SE(Q)
m
In 3He-B
In relativistic field theory
Q=
d3x[i(f* dtf - fdtf* )]
f (r t) = exp(- imt) f (r)
d3x[
I
D
E(m) =
fI2
-
mIfI2
+ U(IfI)]
Q (r) = S - Sz(r)
S+ (r) = S (r) e iwt
dEd = Dw = gHdd(S,L)
dSz
Q ball creates Persistent signal of NMR in 3He
Yu.M. Bunkov “Persistent Signal; Coherent NMR state Trapped by Orbital Texture”
J. Low Temp. Phys, 138, 753 (2005)
Angles of deflection, degree
100
80
60
40
20
0
0
10
20
30
Position, 0.1 mm
40
50
Angles of deflection, degree
100
80
60
40
20
0
0
10
20
30
Position, 0.1 mm
40
50
Brain Physics in superfluid 3He
Helsinki experiments
A phase
B phase
3He as a dark matter detector
First suggestions
G.R.Pickett in Proc. «Second european worshop on neutrinos and dark matters detectors»,
ed by L.Gonzales-Mestres and D.Perret-Gallix, Frontiers, 1988, p. 377.
Yu.Bunkov, S.Fisher, H.Godfrin, A.Guenault, G.Pickett. in Proc. « International
Workshop Superconductivity and Particles Detection (Toledo, 1994)», ed. by T.Girard,
A.Morales and G.Waysand. World Scientific, p. 21-26.
At about 100 mK at 0.1 cm3 remains only 10 keV
from the level of absolute zero of temperature.
The deposited energy is intimately associated
with the 3He nuclear.
There is no isolated nuclear thermal bath,
separated from electronic and phononic
subsystems!
Number of quasiparticles
Temperature is the density of quasiparticles, that
measured directly by damping of vibrating wire.
10 15
10 14
3 1010
D  keV 
exp ( - ) 

T
kT  K cm3 
10 13
10 12
10 11
100
120
140
160
Temperature (µK)
180
200
4. He is the only substance, which remains liquid at Ultra Low Temperatures.
The external particles are collide with only single nuclear.
There is not effect of "solid body" collision.
5 The nuclear momentum of 3He makes the non-symmetric channel of interaction
visible for dark matter. There is one non paired neutron for 3 nuclons!
6. The neutron capture reaction shows the clear signature of neutrons!
7 The absence of free electrons makes 3He relatively insensitive to
electromagnetic and gamma radiation background.
8. A the lowest temperatures superfluid 3He is absolutely quantum pure matter.
9. Since the 3He pairs have a nuclear magnetic momentum but no electric charge, the superfluid 3He
is transparent to electromagnetic radiation, allowing to employ a very informative NMR methods.
NMR can establish magnetically excited quantum state. The latter can be considered rather as
metastable state, where instability can be triggered by a small deposit of energy. This variant of
particle detector can be tested in future.
The small heat capacity, the absolute purity, the liquid state and the relative transparency to gamma
radiation background make superfluid 3He a very sensitive nuclear collision detector.
Muon histogram:
quenching factor ≈ 25 %
Geant4 simulation
Experiment
Low energy electrons
Quenching factor = 26%
• resolution of low
energy emission
spectrum of 57Co
• Comparison to 14
keV peak with
bolometric calibration
 Energy deficit of
fUV(e-,14keV)≈265%
Analysis LPSC, d5
S/B>5
cell B (with source)
cell A (without source)
Threshold ~ 1 keV
0.266
~ 8 keV
line width (Hz)
0.265
0.264
0.263
0.262
0.261
0.26
8500
0
9000
9500
100
1 104
time (s)
Threshold ~ 1 keV
1.05 10
200
4
1.1 10 4
1.15
10 4
300
3He
P N
P
Huge density of non-paired neutrons
Spin dependent interaction
Ultra Low Temperature
Instrumentation for Measurements in
Astrophysics
Collaboration:
ULTIMA
CRTBT – CNRS, Grenoble, France
LPNC – CNRS, Grenoble, France
Kyoto University, Japan
University Fourie, Grenoble, France
Helsinki Technological University, Finland
Centre “Cosmion”, Moscow, Russia
(2006-2008)
Stage 1: New refrigerator for cooling 100g of 3He to 100 mK
Going to underground site.
Develop the Ionization channel.
Try to use NMR for thermometry.
Goal: Try to found axial interacted Dark matter.
(2008-??)
Stage 2: Detector with 1 kg of 3He for ultimate search of dark matter