the forces exerted on the neutron can give energy for nothing!
DESCRIPTION
Paradox IV (Aharonov). The forces exerted on the neutron can give energy for nothing!. d. d. Paradox V. W. Shockley and R.P. James, PRL 171, 1370 (1967). A cannon with no recoil. Paradox V. W. Shockley and R.P. James, PRL 171, 1370 (1967). A cannon with no recoil. - PowerPoint PPT PresentationTRANSCRIPT
c
Vd
d EdF
d
V
V
The forces exerted on the neutron can give energy for nothing!
Paradox IV (Aharonov)
W. Shockley and R.P. James, PRL 171, 1370 (1967)
A cannon with no recoil
Paradox V
An isolated system consists of a current loop (two oppositely rotating and oppositely charged disks) and a charge which are originally at rest.
When the current dies out, the charge starts moving, while the disks apparently stay in place.
W. Shockley and R.P. James, PRL 171, 1370 (1967)
A cannon with no recoil
Paradox V
Resolution of Paradoxes V, IV,III (Re)discovery of “hidden momentum”
A current loop in a static electric field has a nonzero linear momentum Y. Aharonov, P. Pearle, and L. Vaidman, PRA 38, 1863 (1988)
When the current stops, the hidden momentum of the current loop is transferred to the mechanical momentum of the tube. The loop recoils to the left.
Resolution of Paradox V (recoil-free cannon)
Resolution of Paradoxes V, IV,III (Re)discovery of “hidden momentum”
A current loop in a static electric field has a nonzero linear momentum Y. Aharonov, P. Pearle, and L. Vaidman, PRA 38, 1863 (1988)
There is no recoil-free cannon.
Resolution of Paradox V (recoil-free cannon)
When the current stops, the hidden momentum of the current loop is transferred to the mechanical momentum of the tube. The loop recoils to the left.
Resolution of Paradox IV
0
a0
F
dt
but
hiddenpVmp
dt
pdF hidden
exactly 0
a
ELECTRON
The motion of the electron is identical to the motion of the neutron
Resolution of Paradox III
The motion of the neutron inside the interferometer is the same with or without the line of charge.
ELECTRON
NEUTRON
LINE OF CHARGE
NEUTRON
0F
0F
AC dual to AB
0
a 0
a
The motion of the electron inside the interferometer is the same with or without the solenoid
LINE OF CHARGE
NEUTRON
Aharonov-Bohm Effect Aharonov-Casher Effect
SOLENOID
ELECTRON
Paradox I is an unavoidable property of both Aharonov Bohm and Aharonov Casher effects which makes them nonlocal topological effects
Paradox I At every place on the paths of the wave packets of the particle there is no observable action, but nevertheless, the relative phase is obtained.
Conclusion
How comes hidden momentum?A current loop in a static electric field has a nonzero linear momentum
Hint: paradox VIParadox of Two Lorentz Observers
Paradox VICharged particle, charged plate, and two Lorentz Observers
Alice’s view
Paradox VICharged particle, charged plate, and two Lorentz Observers
Bob’s view
iq
iV
0
ii
iVq
00
i
iiVm 0
i
iiVm
c
Epp hiddentot
The current loop model: free charges moving inside a frictionless tube
E
p hid
Hidden momentum
(This and other models: L. Vaidman, AJP 58, 978 (1990))
0
2
2
0
1
i itot i i
i i i
m Vp mV
Vc
Bohm versus Everett
21st-century directions in de Broglie-Bohm theory and beyondTHE TOWLER INSTITUTE The Apuan Alps Centre for Physics Vallico Sotto, Tuscany, Italy
30.08.2010
Hope: Today’s physics explains all what we see.
Big hope: Today’s physics explains All.
Bohm and Everett are candidates for a final theory.
The quantum mechanical formalism does not provide physicists with a ‘pictorial’ representation: the ψ-function does not, as Schrödinger had hoped, represent a new kind of reality. Instead, as Born suggested, the square of the absolute value of the ψ-function expresses a probability amplitude for the outcome of a measurement.
Bohr (SEP):
Bohr and today’s majority of physicists gave up the hopeI think, we should not.
All is iR
and
Bohm:
All is Everett:
All is Many-Worlds Everett:
The Quantum World Splitter Choose how many worlds you want to split by pressing one of the red dice faces.
http://qol.tau.ac.il/TWS.html
left right
http://qol.tau.ac.il/TWS.html
right
http://qol.tau.ac.il/TWS.html
A B
World-splitter of Tel Aviv University
A B
World-splitter of Tel Aviv University
A B
World-splitter of Tel Aviv University
All
All is a closed system which can be observed
All
All is a closed system which might include an observer which can be observed
What is ψ ?There is no sharp answer. Theoretical physicists are very flexible in adapting their tools, and no axiomization can keep up with them. But it is fair to say that there are two core ideas of quantum field theory. First: The basic dynamical degrees of freedom are operator functions of space and time- quantum fields.Second: The interaction of these fields are local in space and time. F. Wilczek (in Compendium of Quantum Physics, 2009)
( ( ), ( ))a aA r r ( )r
Bohm: At the end of the day, the only variables we observe are positions.
Space is taken for granted
( )r
Everett:
( )r
Bohm:
All isevolving according to deterministic equations
All is
1 2( , ,...., , )Nr r r t
Everett:
Bohm: 1 2( ), ( ),...., ( )Nr t r t r t
and
1 2( , ,...., , )Nr r r t
evolving according to deterministic equation
All is particlesevolving according to Newton’s equations
Laplacian determinism
A CENTURY AGO:
1 2( ), ( ),...., ( )Nr t r t r t
Everett Interpretation
Observation
Laplacian determinism
Observation 1 2( ), ( ),...., ( )Nr t r t r t
1 2( , ,...., , )Nr r r t
TRIVIAL
Bohmian mechanics
Observation 1 2( ), ( ),...., ( )Nr t r t r tTRIVIAL
HARD
Everett Interpretation
Observation
Laplacian determinism
Observation 1 2( ), ( ),...., ( )Nr t r t r t
1 2( , ,...., , )Nr r r t
TRIVIAL
HARD
Bohmian mechanics
Observation 1 2( ), ( ),...., ( )Nr t r t r tTRIVIAL
Everett Interpretation
Many parallel
Observations
Laplacian determinism
Observation 1 2( ), ( ),...., ( )Nr t r t r t
1 2( , ,...., , )Nr r r t
TRIVIAL
Bohmian mechanics
Observation 1 2( ), ( ),...., ( )Nr t r t r tTRIVIAL
HARD
An observer has definite experience.
Everett’s Relative State World
What is “a world” in the Everett Interpretation ?
A world is the totality of (macroscopic) objects: stars, cities, people, grains of sand, etc. in a definite classically described state.
The MWI in SEP
OBSERVER RESTi i i
1 2 ...OBJECT OBJECT OBJECTK RESTi i i i i
OBJECT
i is a Localized Wave Packet for a period of time
1 2( , ,...., , )Nr r r tmany
worlds
1 2( , , ...., , )
Ni r r r t Observation i world i
1 21 2 ( , , ...., , )( , ,...., , )NN i i r r r tr r r t
Many parallel
Observations
What is our world in the Bohmian Interpretation ?
Observation 1 2( ), ( ),...., ( )Nr t r t r t
We do not observe (experience) 1 2( , ,...., , )Nr r r t
Bohmian trajectories
CONTEXTUALITY
EPR
V
V
V V
V V
VV
VV
VV
V
V
V
V
V V
V
V
/ 3V
V
1 0.5
1 0.5 3
V V V
V/ 3V
V
VVV
VV
V
MZI
IFM
Counterfactual Computation
0
Surrealistic trajectories
A tale of a single world universe
The king forbade spinning on distaff or spindle, or the possession of one, upon pain of death, throughout the kingdom
A tale of a single world universe The king forbade performing quantum measurements, or the possession of quantum devices, upon pain of death, throughout the kingdom
PhotomultipliersGeiger countersStern Gerlach devicesBeam splittersDown conversion crystalsQuantum dotsQuantum tunnelingPhotodiods……The Quantum World Splitter
1 2 ...OBJECT OBJECT OBJECTKUNIVERSE WORLD REST
Quantum states of all macroscopic objects are Localized Wave Packets all the time
A tale of a single world universe
1 21 2 1 2( , ,...., , ) ( ) ( )... ( )NWORLD
N Nr r r t r r r Zero approximation: all particles remain in product LWP states
Particles which do not interact strongly with “macroscopic objects” need not be in LWP states.
1 21 2( ) ( )... ( )KWORLD REST
Kr r r
( )nnr
Particles which make atoms, molecules, etc. can (and should be) entangled among themselves. Only states of the center of mass of molecules, cat’s nails etc. have to be in LWP states.
21 1 2 1
1 21 1 2 2( ) ( ) ( ) ( )... ( ) ( )M
M
WORLD CM CM CM RESTCM rel i j CM rel i j CM rel Mi Mjr r r r r r r r r
Quantum states of all macroscopic objects are Localized Wave Packets all the time
A tale of a single world universe
1 21 2 1 2( , ,...., , ) ( ) ( )... ( )NUNIVERSE
N Nr r r t r r r
21 1 2 1
1 21 1 2 2( ) ( ) ( ) ( )... ( ) ( )M
M
WORLD CM CM CM RESTCM rel i j CM rel i j CM rel Mi Mjr r r r r r r r r
Observation 1 21 2( ) ( )... ( )N
Nr r r TRIVIAL
Almost the same as in
( )r
( )r of a cat!
Bohmian trajectories
Two worlds universe
This is a multiple worlds universe
Two worlds universe
A
B
A
B
Two worlds universe One world does not disturb the other
A
B
Two worlds universe One world does not disturb the other
Two worlds universe
A
B
Preferred basis:
| | | |MD A MDB ENVA R R R | | | |MD A MDB ENVA V R R | | | |MD A MDB ENVA V R A
| , |A B | | | |, | , |
2 2
A B A B
or
STABILITY
Two worlds universe
A
B
Preferred basis:
| | | |MD A MDB ENVA R R R | | | |MD A MDB ENVA V R R | | | |MD A MDB ENVA V R A
| | | |MD A MDB ENVB R R R
| | | |MD A MDB ENVB R V R | | | |MD A MDB ENVB R V B
| , |A B | | | |, | , |
2 2
A B A B
or
STABILITY
Two worlds universe
A
B
Preferred basis:
| | | |MD A MDB ENVA R R R | | | |MD A MDB ENVA V R R | | | |MD A MDB ENVA V R A
| | | |MD A MDB ENVB R R R
| | | |MD A MDB ENVB R V R | | | |MD A MDB ENVB R V B
| , |A B | | | |, | , |
2 2
A B A B
or
| | | |MD A MDB ENVR R R | | | | | |
|2
MD A MDB MD A MDBENV
A V R B R VR
| | | | | | | |
2MD A MDB ENV MD A MDB ENVA V R A B R V B
| | | | | | | | | | | || |
2 2MD A MDB ENV MD A MDB ENV MD A MDB ENV MD A MDB ENVV R A R V B V R A R V B
STABILITY