Frascati 2006, Beatrix C. Hiesmayr

Testing QM in Testing QM in Particle PhysicsParticle Physics

Physics Particle Physics Quantum Theory

bybyBeatrix C. HiesmayrBeatrix C. Hiesmayr

Institute for Theoretical PhysicsUniversity of Vienna

Austria

experimental phenomenological conceptual mathematical aspects

Frascati 2006, Beatrix C. Hiesmayr

Testing QM in high energy physics

Bell inequalitiesBell inequalities How to measure entanglement or decoherence?How to measure entanglement or decoherence?

““Kaonic” Quantum ErasersKaonic” Quantum Erasers “Erasing the Past and Impacting the Future”

Bohr’s Complementarity in two-path interferometyBohr’s Complementarity in two-path interferomety (kaons are doubleslits given freely by Nature)

Duality in Particle PhysicsDuality in Particle Physics

•Bertlmann, Durstberger, Hiesmayr, Phys. Rev. A 68 (2003) 012111.

•Bertlmann, Grimus, Hiesmayr,Phys. Rev. D 60 (1999) 114032.

Bramon,Garbarino, Hiesmayr, Phys. Rev. A 69 (2004) 022112.

•Hiesmayr, Found. of Phys. Lett. 14 (2001).•Bertlmann, Bramon, Garbarino, Hiesmayr, Phys. Lett. A 332, (2004) 355.•Bertlmann, Grimus, Hiesmayr, Phys. Lett. A 289 (2001) 21.•Bertlmann, Hiesmayr, Phys. Rev. A 63 (2001) 062112.

•Bramon, Garbarino, Hiesmayr, Phys. Rev. Lett. 92 (2004) 020405.

•Bramon, Garbarino, Hiesmayr, Phys. Rev. A 68 (2004). 062111

Bramon, Garbarino, Hiesmayr, Eur. J. Phys. C 32 (2004) 377.

KEK (Japan) & DANE?

Aharanov & Zubairy: Science 307:875, 2005

Frascati 2006, Beatrix C. Hiesmayr

Outline

R. Feynman:“The double slit

contains the only mystery.”

“If there is any place where we have a chance to test the main principles of

quantum mechanics in the purest way---does the superposition of amplitudes

work or doesn't it?---this is it.”

R. Feynman about neutral kaons:

Frascati 2006, Beatrix C. Hiesmayr

Neutral kaons viewed a little differently:

2 20 12

( )S L

S Limt tiL

t t mSK e K e Kt

Kaon in time: short-lived state long-lived state

10 1S

L

10 ...decay width of K1/ 600 ...decay width of K

0.5 ...mass difference

S s

L S

L S Sm m m

„A kaon is a kind of double slit“

Strangeness:

Mass-eigenstates:

Feynman diagram

0 0

0 0

S K K

S K K

,S LK K

0 12 S LK K K

Bramon,Garbarino, Hiesmayr, Phys. Rev. A 69 (2004) 022112.

Frascati 2006, Beatrix C. Hiesmayr

“Erasing the past and impacting the future”

1801 Thomas Young:Photons interfere!

Interference lost because photon watched (gain which way info)!

Erasing the which way info brings interference back!No wonder Einstein would be confused!

1982 Drühl & Scully:

Frascati 2006, Beatrix C. Hiesmayr

ComplementarityComplementarity

The observation of an interference pattern and the adquisition of which-way information are mutually exclusive.

Quantum systems possess properties that are equally real but mutually exclusive!

wave-particle duality

Bohr’s principle of complementarity:

Interferometric duality:

Frascati 2006, Beatrix C. Hiesmayr

Quantitative complementarityQuantitative complementarity

How to quantify?How to quantify?

Greenberger and Yasin (1988):

Englert (1996)

220 ( 1) ( )V P yy y

predictability=a priori which-way knowledge

fringe visibilitypure

Frascati 2006, Beatrix C. Hiesmayr

Complementarity for kaonsComplementarity for kaons

0( ) ( ) ( ) ( )1 cos( )y y y yI N F V

20

1cosh(

()

)tt

V

Visibility (“wave-like” property):

Intensity:

20 0 0 12

2

20 0 0 12

2

1( , ) ( ) 1 cos( )cosh( )

1( , ) ( ) 1 cos( )cosh( )

t t tt

t

K K K m

K K K mt tt

Neutral kaons:

Frascati 2006, Beatrix C. Hiesmayr

Complementarity for kaonsComplementarity for kaons

220 ( 1) ( )V Pt t t

( ) ( ) ( , ) ( , ) tanh) )( (2I II S Ly p y p y K t K t tP

Predictability (“particle-like” property):

20

1cosh(

()

)tt

V

Visibility (“wave-like” property):

Bohr’s complementarity relation:

Frascati 2006, Beatrix C. Hiesmayr

ComplementaryComplementary

Physics Quantum Theory Particle Physics

Nuclear Physics

Quantitative complementarity in two-path interferometry:

1. Double–slit-like experiments2. Particle oscillations3. Scattering of identical particles

unifiedunified formalism formalism in terms of in terms of ``complementarity´´``complementarity´´

Frascati 2006, Beatrix C. Hiesmayr

Quantum eraser for kaons?Quantum eraser for kaons?

•Ou, Wang, Zou & Mandel 1990•Zou, Wang & Mandel 1991•Herzog, Kwiat, Weinfurter & Zeilinger 1995•Kwiat, Steinberg & Chiao 1992•Tsegaye and Björk 2000•Walborn, Terra Cunha, Padua & Moken 2002•Kim, Yu, Kulik, Shih & Scully 2000•Tifonov, Björk, Sönderholm & Tsegaye 2002

Atoms: Dürr, Rempe 2000

Entangled photons:

Scully, Drühl 1982: gedanken experiment concerning the possibility to erase information contained in quantum states

Experiments:

Frascati 2006, Beatrix C. Hiesmayr

Experiment: Herzog et al.

12 object meter object meter

H V V Hie

second passage first passage

normalized to surviving kaon pairs

rlrl LKSKmiSKLK ee

e

21

1

1

Frascati 2006, Beatrix C. Hiesmayr

Experiment: Kim et al.

choice to show which way info or not is partially active!

Frascati 2006, Beatrix C. Hiesmayr

Measurements:

“Active” measurement:Strong interactions:K0+p K++nK0+p +K0+n K-+p, +

“Passive” measurement:Semileptonic decay modes Q=S:K0(sd)(ud)+l++l

K0(sd) (ud)+l-+l

“Active” measurement:Free propagation:

any decay mode observed before t+4.8 S are identified as KS at time t

Misidentification: few parts in 10-3!

“Passive” measurement:Sensitive to the decay modes:

2 ’s are identified as KS

3 ’s are identified as KL

Misidentification: few parts in 10-3!

Strangeness basis: 000 KK

Lifetime basis: 102.3

1Re2 3

2

LS KK

Frascati 2006, Beatrix C. Hiesmayr

(A) Active Eraser with active measurements

object system

meter systemS, tl S, tr

0

T, tr0

left (object) right (meter)

1.Setup (matter block remove):

active S active T2.Setup (matter block inserted):

active S active S

source

Frascati 2006, Beatrix C. Hiesmayr

(B) Partially active eraser with active measurements

object system

meter systemS, tl S, tr

0

left (object) right (meter)

active S active T, active S

source

T

partially active choice due to instability of kaon

Frascati 2006, Beatrix C. Hiesmayr

(C) Passive eraser with passive measurements

object system

meter systemS, tl

S

left (object) right (meter)

active S passive T, passive S

source

T T

Frascati 2006, Beatrix C. Hiesmayr

(D) Passive eraser with passive measurements

left (??object??) right (??meter??)

passive T, passive S passive T, passive S

T TS

S

Frascati 2006, Beatrix C. Hiesmayr

Summary of “kaonic” eraser

• remarkably all these QE options lead to the same probabilities!•this is even true regardless the temporal ordering•demonstrates nicely the very nature of QE: sorting events

Up to our opinion: It should be possible to test it at DANE!

Frascati 2006, Beatrix C. Hiesmayr

Questions to the experimenters:

•Are active measurements possible?•Which initial entangled states can be produced (besides the antisymmetric Bell state)?•Can the CP state |K1> be somehow measured? •Or can another superposition be measured?•Can the long lived state |KL> be “boosted”?