High Precision Experiments with Cold and Ultra-Cold Neutrons

Hartmut AbeleVienna, 1 December 2012

qBOUNCE: Spectroscopy of Gravity

a, A, B, C

Show Case I: Test of Gravitation at Short Distances with Quantum Interference

Julio Gea-Banacloche, Am. J. Phys.1999

Quantum interference: sensitivity to fifth forces

Hartmut Abele, Atominstitut, TU WienTim

eRafael Reiter, Bernhard Schlederer, David Sepp

Simulation: Reiter, Schlederer, Seppi

Height, 40 µm

Key Technique: Gravity Resonance Spectroscopy

3

E h

• atomic clocks• 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

|1 > 1.4 peV

|3 > 3.32 peV

Nature Physics, 1 June 2011

High Precision - Low EnergyHartmut Abele, Atominstitut, TU Wien

Rabi-Gravity-Spectroscopy

GRS: T.J., H.A. et al., Nature Physics 2011

4

|1 > 1.4 peV

|3 > 3.32 peV

a 2-level system can be considered as a Spin ½ - System

Vibrating mirrorAlternating Magnetic gradient

fields

QS: V.N., H.A. et al.,Nature 2002

Side-band excitation

Gähler, Felber, Golub et al.

5

The kicked rotor

M. Bienert, F. Haug and W. P. Schleich, Raizen

6Hartmut Abele, Vienna University of Technology

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

Outline

7

Spallation SourceReactor source

Neutron sources

9Hartmut Abele, Technische Universität Wien

10

Neutron Production

10-7

Velocity v [m/s]

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

Hartmut Abele, Technische Universität München 13Hartmut Abele 13

Quantum Bounce ?Cold-Source at 40 K

Hydrogen Atom- Electron bound in proton

potential- Bohr radius <r> = 1 A- Ground state energy of 13 eV- 3 dim.- Schrödinger Equ.

- Legrendre Polynomials

System Neutron & Earth- Neutron bound in the gravity

potential of the earth- <r> = 6 µm- Ground state energy of 1.4 peV- 1 dim.- Schrödinger Equ.

- Airy Functions

Gravity and Quantum Mechanics

14

)()(2 2

22

zEzmgzzm nnn

Schrödinger equation:

0)0( n

boundary conditions:

0)( lnwith 2nd mirror at height

l

Solutions: Airy-functions: Ai & Bi

En En

1st state 1.41peV

1.41peV

2nd state 2.46peV

2.56peV

3rd state 3.32peV

4.2 peV

V [peV]

Show Case I: Rabi-type Spectroscopy of Gravity

15

Resonance Spectroscopy Technique to explore gravity

T. Jenke, SPP1491-Treffen 2012, Frauenchiemsee

neutronmirror

UCN

State Selection by a rough neutron mirror

• 4.5 days of beam time

• 3600 events (background subtracted)

n

nn ztc 221

2 )()(

)()(2 tfPSFN • fit:

• free parameters:

• result:0

21 ,,,)( zNltcn

track detector

00,0)(

30,0)(

70,0)(

213

212

211

tc

tc

tc

rough mirror

T. Jenke, ÖPG 2012

6 m/s < vx < 7.2 m/s

Horizontal velocity

17Hartmut Abele, Technische Universität München T. Jenke, Diploma thesis, 2008

Frequency Reference for Gravitation

Hartmut Abele, Vienna University of Technology 18

|1 > 1.4 peV

|3 > 3.32 peV

3/2

0 41

nEn

pqpq

pq

EE

Based on 2 natural constants: ⁻ Mass of the neutron m⁻ Planck constant ħPlus Acceleration of earth g

3/122

0 89

mg

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?

constraint on any possible new interaction 19

Axion

10-14 eV Scale

20

21Felicitas Pauss

The cosmological Parameters

Neutrons test Newton

Strength aRange l

23

/1 2( ) (1 )rm mV r G er

la

Hypothetical Gravity Like ForcesExtra 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 fields-

Show Case: Rabi-type Spectroscopy of Gravity

24

Rabi-type experiment:

Resonance Spectroscopy Technique to explore gravity

• realization of gravity resonance method possible• simple setup, no steps• high(er) transmission• upper mirror introduces 2nd boundary condition

Rabi-type experiment with damping

T. Jenke, SPP1491-Treffen 2012, Frauenchiemsee

Gravity Resonance Spectroscopy 2012

25

50 days of beam time, 116 measurements

1 2 , 1 3 , 2 3 and 2 4

• stat. Significance:• stat. accuracy:

• contrast:

%2.2Hz5.679%5.0Hz1.539%0.1Hz4.280%8.0Hz2.258

24

13

23

12

48

%68

pq

T. Jenke, Dissertation (TU Wien, 2011)T. Jenke et.al., arXiv:1208.3875 (2012)

[data 2010]

pq

T. Jenke, ÖPG 2012 10-14 eV Scale

AXION: PDG Exclusion Ranges

26

PDG Exclusion Ranges on Axion masses

27

2 cml

0.2 µml

←

←

Applications I: Spin-dependant short-ranged interactions

28

2axion

118 rr

ncm

ggV

n

ps

l

dayscgg ps

16103/

discovery potential [Setup 2010]:

C.L.%68,µm10l

J.E. Moody, F. Wilczek, Phys. Rev. D30, 131-138 (1984)

3 days of beamtime

T. Jenke et.al., arXiv:1208.3875 (2012)T. Jenke, ÖPG 2012

Chameleon fields, Brax et al. PRD 70, 123518 (2004)

2 Parameters , n

Dark Energy – Scalar Fields

29

Mirrors at z ~ ± d/2Fit 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

qBounce and Chameleons

Applications II: Strongly coupled chameleons

32

A.N. Ivanov et.al., arXiv:1207.0419 (2012)T. Jenke et.al., arXiv:1208.3875 (2012)

22

22

Chameleon 222

n

Pl

zdd

nMmV

T. Jenke, ÖPG 2012

Feedback from FUNDAMENTAL PHYSICS

Convener: T. Soldner, O. Zimmer, H. Abele

Chameleon fields, Brax et al. PRD 70, 123518 (2004)

2 Parameters , n

Dark Energy – Scalar Fields

34

Casimir ForceAtom

Example Rb

r = 1 Micron

Neutron: Casimir force absent

Polarizability extremely small:

35

04

3( ) 2c aV rr

peV

230

04

2,3 103( ) 20.6

ac aV rr

fm

VeVm

peV

4 3

0

41

18

11.6 104

6 10

10

n

n

aD a E

E

Grand Challenges

36

Sensitive to any forceDark energy search- chameleon fields

Dark matter searchLarge extra dimensions Hypothetical gravity like forces

Participating Institutions:

• IST Braunschweig• Univ. Heidelberg• ILL• Univ. Jena • Univ. Mainz

• 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. )

DFG/FWF Priority Programme 1491

• Exzellenzcluster ‚Universe‘ München• Techn. Univ. München*

• PTB Berlin• Vienna University of Technology*

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

39

Parameters• Strength: GF • Quark mixing: Vud

• Ratio: l = gA/gV

5 41 2 2 2

3 7(1 3 ) 2ud

Re

FfV mG c

hl

ObservablesLifetime Correlation ACorrelation BCorrelation CCorrelation aCorrelation DCorrelation NCorrelation QCorrelation RBeta SpectrumProton SpectrumPolarized SpectraBeta Helicity

Electron

Proton

Neutrino

Neutron SpinA

B

C

a

D

R N

Neutron Alphabet deciphers the SM

High Precision - Low Energy• Hartmut Abele, Atominstitut, TU Wien

RQ

v- selector

Spin flipper

PolarizerDecay Volume, 8m

Chopper

Beam stop

Analyzing area

A clean, bright and versatile source of neutron decay products Univ.Heidelberg & TU Wien, Mainz, ILL,FRM2,TU Munich

n-guide + solenoid: field B0

polarized, monochromatic n-pulse n + γ-beam stop

solenoid, field B1

solenoid, field B2

p+ + e− window-framep+ + e− beam

B. Maerkisch talk Berlin 2012

Key Instrument: PERC

• 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

4141

Origin of nature’s lefthandednessStandard Model: Elektroweak interaction 100% lefthanded

Grand unified theories:Universe was left-right symmetric at the beginningParity violation = 'emergent' Order parameter <100%

Neutron decay: Correlation B + A:Mass right handed W-Boson: mR > 280 GeV/c2

Phase: -0.20 < < 0.07

WL WR

Grand Challenges

42

Sensitive to any theory beyond the Standard ModelLeft Right SymmetrySupersymmetryTensor or scalar interactions GUT

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

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

Charge quantization and the electric neutrality of the neutron.

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,

qBOUNCE Summary

46Hartmut Abele, Vienna University of Technology