qBOUNCE: Spectroscopy of Gravity
High Precision Experiments
with Cold and Ultra-Cold Neutrons
a, A, B, C
Hartmut Abele
Vienna, 1 December 2012
Show Case I:
Test of Gravitation at Short Distances with Quantum Interference
DOK TORAT SKOLLEG
Julio Gea-Banacloche, Am. J. Phys.1999
Quantum interference: sensitivity to fifth forces
Simulation:
Reiter, Schlederer, Seppi
Hartmut Abele, Atominstitut, TU Wien
Rafael Reiter, Bernhard Schlederer, David Sepp
PI
Nature Physics, 1 June 2011
DOK TORAT SKOLLEG
PI
Key Technique: Gravity Resonance Spectroscopy
|3 > 3.32 peV
E  h
• atomic clocks
|1 > 1.4 peV
• nuclear magnetic resonance spectroscopy
• spin echo technique
• quantum metrology
• gamma resonance spectroscopy
Test Newton‘s law at short distances:
• String Theories
• Dark Matter
• Dark Energy
Hartmut Abele, Atominstitut, TU Wien
High Precision - Low Energy
3
Rabi-Gravity-Spectroscopy
a 2-level system can be considered as a Spin ½ - System
|3 > 3.32 peV
|1 > 1.4 peV
Vibrating
mirror
Alternating
Magnetic gradient
fields
GRS: T.J., H.A. et al., Nature Physics 2011
QS: V.N., H.A. et al.,
Nature 2002
4
Side-band excitation
Gähler, Felber, Golub
et al.
5
The kicked rotor
M. Bienert, F. Haug and
W. P. Schleich, Raizen
Hartmut Abele, Vienna University of Technology
6
Outline
Gravity Resonance Spectroscopy
- Quantum states in the gravity potential of the earth and
coherence superposition
Search for deviations from Newtons gravity law at short distances
- Large extra dimensions
- Dark matter particles
- Dark energy
Tests of weak interaction with neutron beta-decay experiments
- Experiment PERC
Scientific Programme for ESS /Broad overview of the field
7
Neutron sources
Spallation Source
Reactor source
Hartmut Abele, Technische Universität Wien
9
Neutron Production
10-7
Velocity v [m/s]
10
The future: FRM2, ESS
11
Tool: Ultra-Cold Neutrons
Strong Interaction: V ~ 100 neV
Kinetic Energy: < 100 neV
3m/s < v < 20m/s
Magnetism, Zeeman splitting : 120 neV/T
Energy in the earth‘s gravitational field:
E = mgh 100neV/m
Quantum Bounce
?
Cold-Source at 40 K
System Neutron & Earth
Hydrogen Atom
- Neutron bound in the gravity
potential of the earth
- Electron bound in proton
potential
- <r> = 6 µm
- Bohr radius <r> = 1 A
- Ground state energy of 1.4 peV
- Ground state energy of 13 eV
- 1 dim.
- 3 dim.
- Schrödinger Equ.
- Schrödinger Equ.
- Airy Functions
Hartmut Abele
Abele, Technische Universität München
- Legrendre Polynomials
13
Gravity and Quantum Mechanics
Schrödinger equation:
Solutions: Airy-functions: Ai & Bi
  

 
 n ( z )  En n ( z )

mgz
2
2
m

z


2
2
boundary conditions:
En
En
1st state
1.41peV
1.41peV
2nd state
2.46peV
2.56peV
with 2nd mirror at height
3rd state
3.32peV
4.2 peV
 n (0)  0
 n (l )  0
V [peV]
l
14
Show Case I: Rabi-type Spectroscopy of Gravity
Resonance Spectroscopy Technique to explore gravity
T. Jenke, SPP1491-Treffen 2012, Frauenchiemsee
15
State Selection by a rough neutron mirror
UCN
rough mirror
• 4.5 days of beam time
• 3600 events
track detector
(background subtracted)
neutron
mirror
   cn (t1 ) n ( z )
2
2
2
n
• fit:
N    PSF ( )  f (t )
2
2
• free parameters:
• result:
cn (t1 ) , l , N , z0
c1 (t1 )  0,70
2
c2 (t1 )  0,30
2
c3 (t1 )  0,00
2
T. Jenke, ÖPG 2012
Horizontal velocity
6 m/s < vx < 7.2 m/s
Hartmut Abele, Technische Universität München
T. Jenke, Diploma thesis, 2008
17
Frequency Reference for Gravitation
Based on 2 natural constants:
⁻ Mass of the neutron m
⁻ Planck constant ħ
Plus Acceleration of earth g
 9 m g
0  
 8
2
2
1/ 3



1

E n   0  n  
4

2/3
|3 > 3.32 peV
 pq 
|1 > 1.4 peV
Hartmut Abele, Vienna University of Technology
Eq  E p

 q   p
18
Discoveries: the dark universe
Spectroscopy of Gravity
- It does not use
electromagnetic forces
- It does not use coupling to
em Potential
Hyothetical gravity-like
forces
- Axions?
- Chameleons?
Axion
10-14 eV Scale
constraint on any
possible new interaction
19
20
Felicitas Pauss
21
The cosmological Parameters
Neutrons test Newton
m1  m 2
V (r )  G
(1  a  e r / l )
r
Strength a
Range l
Hypothetical Gravity Like Forces
Extra Dimensions:
The string and Dp-brane theories predict the existence of extra space-time
dimensions
Infinite-Volume Extra Dimensions: Randall and Sundrum
Exchange Forces from new Bosons: a deviation from the ISL can be induced by the
exchange of new (pseudo)scalar and (pseudo)vector bosons
• Axion - - - - - - - - - - - - - - - - - - - → 0.2 µm < l < 0.2 cm
• Scalar boson. Cosmological consideration
• Bosons from Hidden Supersymmetric Sectors
• Gauge fields in the bulk (ADD, PRD 1999) - - - - →106 < a < 109
Supersymmetric large Extra Dimensions (B.& C.) - - - - → a < 106
Chameleon fields23
Show Case: Rabi-type Spectroscopy of Gravity
Resonance Spectroscopy Technique to explore gravity
Rabi-type experiment:
Rabi-type experiment with damping
• realization of gravity resonance
method possible
• simple setup, no steps
• high(er) transmission
• upper mirror introduces
2nd boundary condition
T. Jenke, SPP1491-Treffen 2012, Frauenchiemsee
24
50 days of beam time,
116 measurements
Gravity Resonance Spectroscopy 2012
[data 2010]
 pq
 pq
1  2 , 1  3 , 2  3 and 2  4
• stat. Significance: 48
• stat. accuracy:  12  258.2 Hz  0.8%
 23  280.4 Hz  1.0%
 13  539.1 Hz  0.5%
 24  679.5 Hz  2.2%
• contrast:
T. Jenke, ÖPG 2012
68%
T. Jenke, Dissertation
-14 (TU Wien, 2011)
T. Jenke et.al., arXiv:1208.3875 (2012)
10
eV Scale
25
AXION: PDG Exclusion Ranges
26
PDG Exclusion Ranges on Axion masses
←
l  2 cm
←
l  0.2 µm
27
Applications I:
Spin-dependant short-ranged interactions
Vaxion
gs g p     1 1 

 n   2 
8 mn c
 lr r 
J.E. Moody, F. Wilczek, Phys. Rev. D30, 131-138 (1984)
discovery potential [Setup 2010]:
3  1016
g s g p / c 
days
l  10 µm , 68% C.L.
3 days of
beamtime
T. Jenke et.al., arXiv:1208.3875 (2012)
T. Jenke, ÖPG 2012
28
Dark Energy – Scalar Fields
Chameleon fields, Brax et al. PRD 70, 123518 (2004)
2 Parameters , n
29
qBounce and Chameleons
Mirrors at z ~ ± d/2
Fit to numerical solution
qBounce and Chameleons
Bounds on coupling 
- By comparing transition
frequency with theoretical
expectation:
- as long as  > 105
- Cite as: arXiv:1207.0419v1
Applications II:
Strongly coupled chameleons
VChameleon

m  n  2   d2
2
  z  

 
M Pl  2 d  2

2
n2
A.N. Ivanov et.al., arXiv:1207.0419 (2012)
T. Jenke et.al., arXiv:1208.3875 (2012)
T. Jenke, ÖPG 2012
32
Feedback from FUNDAMENTAL PHYSICS
Convener: T. Soldner, O. Zimmer, H. Abele
Dark Energy – Scalar Fields
Chameleon fields, Brax et al. PRD 70, 123518 (2004)
2 Parameters , n
34
Casimir Force
Atom
Example Rb
3 c a0
V (r ) 
2 r 4
r = 1 Micron
a 0  2, 3  1023
3 c a0
V (r ) 
2 r 4
 0.6peV
35
Neutron:
Casimir force absent
Polarizability extremely
small:
an  11.6  104 fm3
D  4 0an E
V
 6  10 eV  E  
m 
 1018 peV
41
Grand Challenges
Sensitive to any force
Dark energy search
- chameleon fields
Dark matter search
Large extra dimensions
Hypothetical gravity like
forces
36
DFG/FWF Priority Programme 1491
Participating Institutions:
• IST Braunschweig
• Exzellenzcluster ‚Universe‘ München
•
•
•
•
• Techn. Univ. München
Univ. Heidelberg
ILL
Univ. Jena
Univ. Mainz
*
• PTB Berlin
• Vienna University of Technology*
• Priority Areas
• CP-symmetry violation and particle physics in the early universe.
• The structure and nature of weak interaction and possible extensions of
the Standard Model.
• Tests of gravitation with quantum objects
• Charge quantization and the electric neutrality of the neutron.
• New Infrastructure (UCN-Source, cold Neutrons)
-
* Coordinators (S. Paul, H.A. )
Priority Programme 1491
Research Area A: CP-symmetry violation and particle physics in the
early universe
- Neutron EDM E = 10-23 eV
Research Area B: The structure and nature of weak interaction and
possible extensions of the Standard Model
- Neutron -decay V – A Theory
Research Area C: Relation between gravitation and quantum theory
- Neutron bound gravitational quantum states
Research Area D: Charge quantization and the electric neutrality of
the neutron
- Neutron charge
Research Area E: New measuring techniques
- Particle detection
- Magnetometry
- Neutron optics
DOK TORAT SKOLLEG
Neutron Alphabet deciphers the SM
A
Observables
Parameters
• Strength: GF
• Quark mixing: Vud
• Ratio: l = gA/gV
Electron
a
•

D
R
C
 1
Neutron Spin
B
N
Q
Proton
Neutrino
R
R
5 4
f
m
e c
 V ud 2G F 2 (1  3l 2 )
2 3 h 7
Hartmut Abele, Atominstitut, TU Wien
High Precision - Low Energy
Lifetime 
Correlation A
Correlation B
Correlation C
Correlation a
Correlation D
Correlation N
Correlation Q
Correlation R
Beta Spectrum
Proton Spectrum
Polarized Spectra
Beta Helicity
39
PI
DOK TORAT SKOLLEG
Key Instrument: PERC
PI
A clean, bright and versatile source of neutron decay products
Univ.Heidelberg & TU Wien, Mainz, ILL,FRM2,TU Munich
• High Flux :  = 2 x 1010 cm-2s-1
 Decay rate of 1 MHz / metre
• Polarizer:
99.7 ± 0.1 %
• Spin Flipper: 100.05 ± 0.1 %
• Analyzer:
100 % 3He-cells
Polarizer
B. Maerkisch
talk Berlin 2012
Chopper
Spin flipper
v- selector
Decay Volume, 8m
Analyzing area
n-guide + solenoid: field B0 Beam stop
polarized, monochromatic
solenoid, field B2
n-pulse
p+ + e− window-frame
n + γ-beam stop
solenoid, field B1 p+ + e− beam
Origin of nature’s lefthandedness
Standard Model:
Elektroweak interaction 100% lefthanded
Grand unified theories:
Universe was left-right symmetric at the beginning
Parity violation = 'emergent' Order parameter <100%
WL
WR
Neutron decay: Correlation B + A:
Mass right handed W-Boson: mR > 280 GeV/c2
Phase:
-0.20 < < 0.07
41
Grand Challenges
Sensitive to any theory beyond the Standard Model
Left Right Symmetry
Supersymmetry
Tensor or scalar interactions
GUT
42
Priority Programme 1491
Research Area A: CP-symmetry violation and particle physics in the
early universe
- Neutron EDM
Research Area B: The structure and nature of weak interaction and
possible extensions of the Standard Model
- Neutron -decay
Research Area C: Relation between gravitation and quantum theory
- Neutron bound gravitational quantum states
Research Area D: Charge quantization and the electric neutrality of
the neutron
- Neutron charge
Research Area E: New measuring techniques
- Particle detection
- Magnetometry
- Neutron optics
The Future: Ramsey-Method
Hartmut Abele, Vienna University of Technology
44
Charge quantization and the electric neutrality of the neutron.
Since the Standard Model value for qn requires extreme fine
tuning, the smallness of this value may be considered as a hint for
GUTs, where qn is equal to zero.
Improve limit by two orders of magnitude
qBOUNCE Summary
Progress Report with Galileo in Quantum Land
- qBounce: first demonstration of the quantum bouncing ball
- Dynamics: time evolution of coherent superposition of Airy-eigenfunctions
- Realization of Gravity Resonance Spectroscopy:
-
Coherent Rabi-Transitions,
|1> |2>
|1> |3>, see Nature Physics, 1 June 2011
|2>  |3>, |2>  |4>
- New Tool for
- A Search for a deviation from Newton‘s Law at short distances, where
polarizability effects are extremely small ,
see H.A. et al., PRD 81, 065019 (2010) [arXiv:0907.5447 ]
- A quantum test of the equivalence principle
- Direct limits on axion coupling / chameleons at short distances,
Hartmut Abele, Vienna University of Technology
46