2. Chapter 2
Beyond Space and Time:
The Quantum Realm
A cosmos in the lab
Andreas Albrecht ponders a study of the physicists
who grapple with the origins of the Universe.
Andreas Albrecht is a theoretical physicist
at the University of California, Davis.
e-mail: ajalbrecht@ucdavis.edu
Ernst Specker:
Quantum contextuality
Nature 542 (2017) 164
3. “Suarez …found a new way
to fit a deity into the picture,
by identifying the “many
worlds” proposed by US
physicist Hugh Everett with
thoughts in the “mind of
God”.
Andreas Albrecht, Nature 542 (2017) 164
Ernst Specker: Quantum contextuality
22. The Solvay Congress: Brussels 23-27.10.1927
[first row] (1) I. Langmuir, (2) M. Planck, (3) M. Curie, (4) H.A. Lorentz, (5) A. Einstein,
(6) P. Langevin, (7) C.E. Guye, (8) C.T.R. Wilson, (9) O.W. Richardson
[second row] (1) P. Debye, (2) M. Knudsen, (3) W.L. Bragg, (4) H.A. Kramers, (5) P.A.M. Dirac,
(6) A.H. Compton, (7) L.V. de Broglie, (8) M. Born, (9) N. Bohr
[third row] (1) A. Piccard, (2) E. Henriot, (3) P. Ehrenfest, (4) E. Herzen, (5) Th. de Donder, (6) E.
Schroedinger, (7) E. Verschaffelt, (8) W. Pauli, (9) W. Heisenberg, (10) R.H. Fowler, (11) L. Brillouin.
1. Nonlocality at detection
This version of the classic photo has been "embellished" by PhysLINK's creator: Anton Skorucak.
23. Light going trough a slit reaches a screen.
Deciding at which point the detection
happens requires nonlocal coordination
between all the detection units.
Nonlocality at detection provoked Einstein
in the Solvay Congress 1927, and
led thereafter to the EPR controversy 1935.
1. Nonlocality at detection
Einstein realized that
the question “at what time the
‘wave’ hits the detector” matters in
quantum physics!
24. Alice
?
BS
Bob
1. Nonlocality at detection
Decision at detection
(Collapse of the wave function)
implies
coordination at a distance between detectors
Welcome the Qubit!
Alice
1
0
1
0
Bob
0
1
1
0
25. Single-photon space-like antibunching
Thiago Guerreiro a, Bruno Sanguinetti a, Hugo Zbinden a, Nicolas Gisin a, Antoine Suarez b,∗
a Group of Applied Physics, University of Geneva, 1211 Geneva 4, Switzerland
b Center for Quantum Philosophy, P.O. Box 304, 8044 Zurich, Switzerland
376 (2012) 2174–2177
Nonlocality at detection,
or the standard quantum «collapse»
1. Nonlocality at detection
27. Nonlocality at detection
Single-photon space-like antibunching
T. Guerreiro, B. Sanguinetti, H. Zbinden, N.Gisin and A. Suarez (2012)
𝑃 𝑇𝐿
(1,1)=𝑃 𝑇𝐿
(0,0)=0
𝑃 𝑇𝐿(1,0)=𝑃 𝑇𝐿(0,1)=0.5
𝑃 𝐴
𝑇𝐿=𝑃 𝐵
𝑇𝐿=0.5
𝑃 𝑆𝐿(1,1)= 𝑃 𝑆𝐿(0,0)=𝑃 𝑆𝐿(1,0)=𝑃 𝑆𝐿(0,1)=0.25
𝑃 𝐴
𝑆𝐿=𝑃 𝐵
𝑆𝐿=0.5
𝑷 𝑺𝑳(1,1)=𝑷 𝑨
𝑺𝑳 ∙ 𝑷 𝑩
𝑺𝑳=0.25
1. Nonlocality at detection
34. http://www.cropcirclesandmore.com/geometries/201101lss.html
“Some 100 yards away from the centre of
Stonehenge stands the so called Heelstone. It is
a single large block of Sarsen stone. On the day
of the summer solstice, usually 21 June, you can,
while standing in Stonehenge, see the sun rise
exactly above the Heelstone. It is a truly magical
moment.”
Classical Determinism
35. Crowds gather at the ancient stone circles of Stonehenge
and Avebury in Wiltshire to celebrate sunrise on the longest
day of the year and the beginning of summer.
36. To my knowledge there are no bookmakers
accepting bets on whether the sun appears at
the left, middle, or right arc!
Schrödinger’s Sun?
37. Interference The counting rate depends on the path-length-difference
Mobile mirror
BS1
BS2 D(+)
D()
Screw
L
20%
80%
T
R
Φ
ΦΦ= ω
l− s
c
: Phase shift because of
the length difference
38. Quantum determinism!
There can be quantum sharp measurements
P(D(+) counts)=1
BS1
BS2
D(+)
D()
50%
R
T
L
100 %
0 %
Notice: The nonlocal qubit and the quantum sharp
measurements is what makes quantum computing
possible!
41. Jeremy’s Butterfield’s perspective on the Multiverse:
Invokes the Eddington fishing-net metaphor (Philosophy of
Physical Science, 1938):
Let us suppose that an ichthyologist is exploring the life of the
ocean. He casts a net into the water and brings up a fishy
assortment. Surveying his catch, he proceeds in the usual
manner of a scientist to systematize what it
reveals. He arrives at two generalizations:
(1) No sea creature is less than two inches long.
(2) All sea creatures have gills.
These are both true of his catch, and he assumes tentatively
that they will remain true however often he repeats it.
42. In applying this analogy, the catch stands for the body of
knowledge which constitutes physical science, and the net for
the sensory and intellectual equipment which we use in
obtaining it. The casting of the net corresponds to
observation; for knowledge which has not been or could not
be obtained by observation is not admitted into
physical science.
An onlooker may object that the first generalization is wrong.
"There are plenty of sea-creatures under two inches long,
only your net is not adapted to catch them." The icthyologist
dismisses this objection contemptuously. "Anything
uncatchable by my net is ipso facto outside the scope of
icthyological knowledge. In short, "what my net
can't catch isn't fish."
43. Or — to translate the analogy — "If you are not simply
guessing, you are claiming a knowledge of the physical
universe discovered in some other way than by the
methods of physical science, and admittedly unverifiable
by such methods. You are a metaphysician. Bah!"
Manyworlds is Metaphysics after all!
44. Leibniz’ Principle
“If there is no possible perceptible difference
between two objects, then these objects are the
same, not superficially, but fundamentally“.
If Alice in our world can never be able to see the other Alice*
in a parallel world, then one should conclude that Alice*
does not belong to our physical reality at all: Things that
cannot in principle be perceived by the senses do not exist
within space-time. And if the existence of Alice* can be
inferred by reasoning but cannot in principle be perceived by
the senses, this means that Alice* exists outside space-time.
51. Jeremy Butterfield: A Philosopher’s Perspective on
Multiverse Proposals
https://arxiv.org/abs/1406.4348
“It all turns on the simple but crucial distinction between
the "is" of identity and the "is" of instantiation. I am happy
to concede that the world we live in instantiates a
mathematical structure, but I deny that it is a
mathematical structure.”
Reality must have an utterly objective description: The
physical multiverse instantiates a pure mathematical
structure. But the physical multiverse is NOT a pure
mathematical structure.
53. Jeremy Butterfield: A Philosopher’s Perspective on Multiverse Proposals
Each possibility is of course non-actual: but real, in some wider
sense than ‘actual’.
What EXACTLY does such a possibility consist of?
This is generally agreed to be a harder
question than e.g. the mind-body problem!
Leibniz’s possible worlds, revived in modern modal metaphysics:
David Lewis’s realism.
Or Ernst Specker’s future contigents and divine omniscience.
A harder question!
The question may stimulate theological research!