neutrons and gravitymoriond.in2p3.fr/.../2_afternoon/1_nesvizhevski.pdf · 2015-03-25 · - neutron...

INSTITUT MAX VON LAUE - PAUL LANGEVINV.V. Nesvizhevsky24.03.1524.03.15

Neutrons and Gravity

Plan of presentation

- Introduction and some references- Emerging related topics- Short-range forces and neutrons- State of the art- Recent improvements- Conclusions and prospects

INSTITUT MAX VON LAUE - PAUL LANGEVIN24.03.1524.03.15 V.V. Nesvizhevsky


INSTITUT MAX VON LAUE - PAUL LANGEVIN24.03.1524.03.15

Our gifts for the Moriond-50 Conference

V.V. Nesvizhevsky and A.Yu. Voronin, Surprising Quantum Bouncing (Imperial College Press, London, UK, 2015)

V.V. Nesvizhevsky



Quantum fall and equivalence principle


More information can be found in:

Series of GRANIT workshops every 4th (Olympic) year; typically 50 participants from 12 countries on 4 continents

GRANIT-2014, 2-7 March 2014, Les Houches, France

proceedings of the last are published in a dedicated issue “Gravitational Quantum Spectroscopy” of Advances in High Energy

Physics.

Reviews. For instance:S. Baessler, Gravitationally bound quantum states of ultracold neutrons and their applications, J. Phys. G 36 (2009) 104005


GRANIT workshops, Gravitational Quantum Spectroscopy


Emerging topics

A broader field of research, which is emerging from firstexperiments on gravitational and whispering-gallery quantumstates of neutrons ([V.V. Nesvizhevsky, H.G. Boerner, A.K.Petukhov, H. Abele, S. Baessler, F.J. Ruess, T. Stoferle, A.Westphal, A.M. Gagarski, G.A. Petrov, and A.V. Strelkov,Quantum states of neutrons in the Earth’s gravitationalfield, Nature 415 (2002) 297], [V.V. Nesvizhevsky, A.Yu.Voronin, R. Cubitt, and K.V. Protasov, Neutron whisperinggallery, Nature Physics 6 (2010) 114])And people involved in this research.


Quantum bouncing

Gravitational and whispering-gallery quantum states of neutrons

Essential features:- The mirror is a uniform

potential barrier, with nointernal structure.

- The particles are reflectedfrom the mirror elastically.

- Ultracold neutrons (UCNs)are unique particles formeasuring such quantumstates.


Quantum bouncing

Gravitational and whispering-gallery quantum states of neutrons

Essential features:- The mirror is a uniform

potential barrier, with nointernal structure.

- The particles are reflectedfrom the mirror elastically.

- Ultracold neutrons (UCNs)are unique particles formeasuring such quantumstates.

My fault. UCNs are not unique particles in this sense. NearlyALL particles with sufficiently large wavelength and smallenergy are reflected elastically from surfaces.


Quantum bouncing

Problem: attractive van der Waals/Casimir-Polderpotential.

Solution: Quantum reflection is the limit oflowest energies (gravitational quantum states!!!)provides nearly total reflection of a particle froma mirror.

The quantum reflection is demonstrated byMaarten de Kieviet.

The importance of the low-energy limit wasnoticed by Alexei Voronin.

INSTITUT MAX VON LAUE - PAUL LANGEVIN

10μm

30μm

20μm

40μm

Height above mirror

An illustration for quantum motion of a particle above a mirror in a gravitational field and that in an accelerated frame. The heights of the ball correspond to most probable heights of a neutron in 5th quantum state.

3

2

4

1

8

9

ng

mE n

n

25.03.15 V.V. Nesvizhevsky

Gravity / Acceleration

INSTITUT MAX VON LAUE - PAUL LANGEVIN

An “artistic” illustration for quantum motion of a particle built of normal matter (left) and antimatter (right) in a gravitational field

?

Gravitational properties of antimatter have never been measured directly

? ?...

25.03.15 В.В. Несвижевский

Matter / Antimatter


“Let us consider another possibility, an atom held together bygravity alone. For example, we might have two neutrons in a boundstate. When we calculate the Bohr radius of such an atom, we findthat it would be 108 light years, and that the atomic binding energywould be 10−27 Rydberg. There is then little hope of ever observinggravitational effects on systems which are simple enough to becalculated in quantum mechanics.” Brian Hatfield in [R.P. Feynman,F.B. Morinigo, and W.G. Wagner (1995) Feynman Lectures onGravitation (Addison-Wesley, USA), p. 11]

Yesterday's sensation is today’s calibration and tomorrow’sbackground” [P.R. Feynman and V.L. Telegdi]

Quantum bouncing


Various realizations

Gravitational quantum states of anti-hydrogen atoms as a toolfor most precision direct measurements of gravitational propertiesof antimatter (GBAR collaboration). Advantages: precisionspectroscopic methods, long observation time, localization in spaceand in energy -> smaller systematic effects and lower costs


Gravitational quantum states of hydrogen atoms as a tool forprototyping the GBAR experiment with antihydrogen atoms (N.Kolachevsky, A.Yu. Voronin, V.V. N. et al) and also as an independentmethod for constraining short-range forces. Advantages: hugestatistics, existing techniques

The prototyping isbased on symmetryof matter andantimatter relativeto electromagneticinteractions



Gravitational quantum states of positronium as a tool tomeasure gravitational fall of positronium with minimum systematicaleffects [P. Crivelli et al, Can we observe the gravitational quantumstates of positronium? Advances in High Energy Physics (2015) inpress]. Advantages: localization in space allows reduction ofsystematic effects



Whispering-gallery quantum states of cold neutrons as asensitive and universal method to explore surfaces (including thestandard surface potentials and fundamental short-range forces).Examples: in-situ monitoring of the growth of thin films, surfacediffusion etc.

Advantages: long observation timethus huge increase in sensitivity; apossibility to use standardreflectometers for cold neutronsavailable in all neutron centers inthe world.



Other options being discussed but not yet developed andformalized:- Astrophysical realizations of quantum bouncing,- Nanoparticles and nanodroplets in the vicinity of surfaces,- Polarized 𝐻𝑒3.



Fundamental short-range forces and neutrons

Short-range forces

Phenomenologically:

- Spin-independent,- Spin-dependent.

Origin:

- Extra light bosons,- Extra spatial dimensions,- Dark matter (chameleons),- Axion-like particles etc

Neutrons

- Electric neutrality,

- Availability of high fluxes ofneutrons with wavelengthscomparable to the spatialscale of extra interactionsto probe,

- High probability of elasticinteraction with matter.


Fundamental short-range forces and neutrons

All measurements with neutrons related to the topic of my talk areperformed at the Institut Max von Laue – Paul Langevin (ILL),Grenoble, France. All measurements involve ILL scientists and alsoall measurements use ILL facilities.


Short-range forces. State of the art (previous Rencontres de Moriond).

I. Antoniadis, S. Baessler, M. Buchner, V.V. Fedorov, S. Hoedl, V.V. N., G. Pignol, K.V. Protasov, S. Reynaud, Yu. Sobolev, « Short-range fundamental forces », Compt. Rendu Acad. Sci 12 (2011) 775.

Particle-particle

Particle-matter

Matter-matter


I. Antoniadis, S. Baessler, M. Buchner, V.V. Fedorov, S. Hoedl, V.V. N., G. Pignol, K.V. Protasov, S. Reynaud, Yu. Sobolev, « Short-range fundamental forces », Compt. Rendu Acad. Sci 12 (2011) 775.

Short-range forces. State of the art (previous Rencontres de Moriond).

Particle-matter

Axion windowof distances


Short-range forces. Recent improvements

Measurements using UCNs in theEDM apparatus at PSI (Villigen,Switzerland) [S. Afach et al,Phys. Let. B (2015) in press].Red line (H) shows the newconstrain derived from thisexperiment.Solid line (I) indicates anachievable constraint that couldbe obtained with a modifiedinstallation.

Slightly better (then H)constraint was recentlymeasured with polarized 𝐻𝑒3

(A.K. Petukhov, G. Pignol et al)



Neutron gravitational states.- Several independent groups (Tokyo, QBounce, GRANIT);- Many new good results in the flow-through mode !! (Qbounce,

Tokyo);- Building a dedicated facility at ILL for experiments with

gravitational quantum states of neutrons in the long-storagemode (GRANIT);

- Neutron results for short-range forces are not yet competitiveto results of short-range gravity and Casimir experiments butthey are rapidly improving (remember that one should improveby 5-6 orders of magnitude; however, no major systematiceffects associated with neutrons have been identifies);

- Significant worldwide effort to increase available densities ofUCNs.



Neutron gravitational states.- Several independent groups (Tokyo, QBounce, GRANIT);- Many new good results in the flow-through mode !! (Qbounce,

Tokyo);- Building a dedicated facility at ILL for experiments with

gravitational quantum states of neutrons in the long-storagemode (GRANIT);

- Neutron results for short-range forces are not yet competitiveto results of short-range gravity and Casimir experiments butthey are rapidly improving (remember that one should improveby 5-6 orders of magnitude; however, no major systematiceffects associated with neutrons have been identifies);

- Significant worldwide effort to increase available densities ofUCNs.

My fault. There are potentially significant systematic effects,particularly in the flow-through mode, but they could be suppressedby properly designing experiments and by making proper analysis ofsystematic effects

INSTITUT MAX VON LAUE - PAUL LANGEVINV.V. Nesvizhevsky

Flow-through mode; limitedobservation time

Storage mode: ultimate observation time and energy resolution

Probabilityof transition

Perturbation frequency, Hz

ijji wEE

Hz25621

eVE 18

min 10

6

12

min 10 EE

E

Transitions could be excited, for instance:

- By periodically varying magnetic field gradient;

-By periodically varying local gravitational field;

-By oscillating mechanically the mirror.

V.V. Nesvizhevsky, and K.V Protasov, “Quantum states of neutrons in the Earth’s gravitational field: state of the art, applications, perspectives” in Edited book on

Trends in Quantum Gravity Research (D.C. Moore, New York, USA, NOVA; pp. 65-107) Ξ “irresistible wish…”

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Transitions between gravitational quantum states


Main Mirror

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Gravitational quantum states in a storage mode



Neutron scattering on noble gases (Xe); the method approaching record sensitivity and having good chances of further success (the talk of Yoshio Kamiyaat GRANIT-2014 Workshop).



Better precision and reliability for experiments with neutronwhispering gallery; record sensitivity; good chances for majorimprovements

INSTITUT MAX VON LAUE - PAUL LANGEVINV.V. Nesvizhevsky25.03.15


Theory

Experiment

Experiment

Theory

Neutrons tunnelingthrough the mirror

Neutrons passing tothe exit of the mirror


1

r

j

1

2

3

V

R3

5

4

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Better precisionand reliability forexperiments withneutron whisperinggallery; recordsensitivity; goodchances for majorimprovements



Conclusions

- The method of gravitational quantum states is rapidly gainingattention and support – good sign! It means that the method ispowerful, and “easy” for implementation.

- Neutron, and neutron-related, constraints for fundamentalshort-range forces are steadily improving due to the effortsof different groups using different methods.

- All these activities are efficient in terms ofresults/resources.

- These tendencies will stay for the observable future.

neutrons and gravitymoriond.in2p3.fr/.../2_afternoon/1_nesvizhevski.pdf · 2015-03-25 · - neutron...

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