Transcript The Puzzling Story of the Neutral Kaon System or what we

Frascati 2006, Beatrix C. Hiesmayr
Testing QM in
Particle Physics
by
Beatrix C. Hiesmayr
Institute for Theoretical Physics
University of Vienna
Austria
Physics   Particle Physics   Quantum Theory
experimental
phenomenological conceptual
aspects
mathematical
Frascati 2006, Beatrix C. Hiesmayr
Testing QM in high energy physics

Bell inequalities

How to measure entanglement or decoherence?
•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.
KEK (Japan) & DAFNE?
•Bertlmann, Durstberger, Hiesmayr, Phys. Rev. A 68 (2003) 012111.
•Bertlmann, Grimus, Hiesmayr,Phys. Rev. D 60 (1999) 114032.

“Kaonic” Quantum Erasers “Erasing the Past and
•Bramon, Garbarino, Hiesmayr, Phys. Rev. Lett. 92 (2004) 020405.
Impacting the Future”
•Bramon, Garbarino, Hiesmayr, Phys. Rev. A 68 (2004). 062111
Aharanov & Zubairy:
Science 307:875, 2005

Bohr’s Complementarity in two-path interferomety
(kaons are doubleslits given freely by Nature)
Bramon,Garbarino, Hiesmayr, Phys. Rev. A 69 (2004)
022112.

Duality in Particle Physics
Bramon, Garbarino, Hiesmayr, Eur. J. Phys. C 32 (2004) 377.
Frascati 2006, Beatrix C. Hiesmayr
Outline
R. Feynman:
“The double slit contains
the only mystery.”
R. Feynman about neutral kaons:
“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.”
Frascati 2006, Beatrix C. Hiesmayr
Neutral kaons viewed a little differently:
Strangeness: S K 0   K 0
S K
0
 K
0
Mass-eigenstates: K , K
S
L
K0 
1
2
K
S
 KL

„A kaon is a kind of
double slit“
Bramon,Garbarino, Hiesmayr,
022112.
Kaon in time:
K (t ) 
0
short-lived state
1
2
e

Feynman diagram
S
2
t  imS t
KS  e
Phys. Rev. A 69 (2004)
long-lived state

L
t  imL t
2
KL

 S  1010 1s ...decay width of K S
 L  1 / 600 S ...decay width of K L
m  m L  m S  0.5  S ...mass difference
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)!
1982 Drühl & Scully:
Erasing the which
way info brings
interference back!
No wonder Einstein would be confused!
Frascati 2006, Beatrix C. Hiesmayr
Complementarity
Bohr’s principle of complementarity:
Quantum systems possess properties
that are equally real but mutually exclusive!
wave-particle duality
Interferometric duality:
The observation of an interference pattern and
the adquisition of which-way information are
mutually exclusive.
Frascati 2006, Beatrix C. Hiesmayr
Quantitative complementarity
How to quantify?
Greenberger and Yasin (1988):
predictability=
a priori which-way knowledge
V02 ( y)  P2 ( y)  1
y
pure
Englert (1996)
fringe visibility
Frascati 2006, Beatrix C. Hiesmayr
Complementarity for kaons
Intensity:
I ( y)  N  F ( y)  1 V0 ( y)  cos( ( y))
Neutral kaons:
( K , t )  K K (t )
0
0
0
0
0
0
( K , t )  K K (t )
Visibility
2
2


1
 12 1 
cos(

m
t
)


cosh(
t
)

2



1
 1 
cos(m t ) 

cosh(
t
)

2

1
2
(“wave-like” property):
1
V0 (t ) 
cosh( 2 t )
Frascati 2006, Beatrix C. Hiesmayr
Complementarity for kaons
Visibility
(“wave-like” property):
1
V0 (t ) 
cosh( 2 t )
Predictability
(“particle-like” property):
P( y)  pI ( y)  pII ( y)  ( K S , t )  ( K L , t )  tanh(

t)
2
Bohr’s complementarity relation:
V02 (t )  P2 (t )  1
t
Frascati 2006, Beatrix C. Hiesmayr
Complementary
Physics   Quantum Theory   Particle Physics
 Nuclear Physics
unified formalism in terms of
``complementarity´´
Quantitative complementarity in two-path interferometry:
1. Double–slit-like experiments
2. Particle oscillations
3. Scattering of identical particles
Frascati 2006, Beatrix C. Hiesmayr
Quantum eraser for kaons?
Scully, Drühl 1982:
gedanken experiment concerning
the possibility to erase information contained in quantum
states
Experiments:
Atoms: Dürr, Rempe 2000
Entangled photons:
•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
Frascati 2006, Beatrix C. Hiesmayr
Experiment: Herzog et al.

 
1
2

 H

object
V
meter

e
i
second passage
 
1
1 e
  


 KL l  KS


normalized to surviving
kaon pairs
r
e
V
object
H
meter



first passage
im
1   
KS
e 2
 KL
l
r





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:
Strangeness basis: K
0
K
0
0
“Active” measurement:
“Passive” measurement:
Semileptonic decay modes Q=S:
Strong interactions:
K0(sd)  p(ud)+l++nl
K0(sd)  p(ud)+l-+nl

0
K +p  L+p
K0+n  K-+p, L+p0
K0+p
K++n
Lifetime basis:
KS KL 
2 Re 
3
2  3.2  10
1 
“Active” measurement:
“Passive” measurement:
Free propagation:
Sensitive to the decay modes:
any decay mode observed
before t+4.8 S are identified
as KS at time t
Misidentification: few parts in 10-3!
Misidentification: few parts in 10-3!
2 p’s are identified as KS
3 p’s are identified as KL
Frascati 2006, Beatrix C. Hiesmayr
(A) Active Eraser with active measurements
T, tr0
object system
source
meter system
S, tr0
S, tl
1.Setup
2.Setup
left (object)
right (meter)
active S
active T
active S
active S
(matter block remove):
(matter block inserted):
Frascati 2006, Beatrix C. Hiesmayr
(B) Partially active eraser with active measurements
object system
T
source
S, tl
meter system
left (object)
active S
S, tr0
right (meter)
active T, active S
 partially active choice due to instability of kaon
Frascati 2006, Beatrix C. Hiesmayr
(C) Passive eraser with passive measurements
object system
S
source
S, tl
T
T
meter system
left (object)
active S
right (meter)
passive T, passive S
Frascati 2006, Beatrix C. Hiesmayr
(D) Passive eraser with passive measurements
T
S
T
S
left (??object??)
passive T, passive S
right (??meter??)
passive T, passive 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
DAFNE!
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”?