1. Schrödinger’s Rainbow:
The Renaissance in Quantum Optical Interferometry

2. Table of Contents • Quantum Technologies
• Schrödinger’s Cat and All That
• Quantum Light—Over the Rainbow
• Putting Entangled Light to Work
• The Yellow-Brick Roadmap

3. Quantum Technology: The Second Quantum Revolution
JP Dowling & GJ Milburn, Phil. Transactions of the Royal Soc. of London
Quantum
Optics
Ion Traps
Cavity QED
Linear Optics
Quantum
Atomics
Bose-Einstein
Atomic Coherence
Ion Traps
Quantum
Information
Processing
Quantum
Mechanical
Systems
Pendulums
Cantilevers
Phonons
Coherent
Quantum
Electronics
Superconductors
Excitons
Spintronics

4. Schrödinger’s Cat and All That

5. Schrödinger’s Cat Revisited

6. Quantum Kitty Review
A sealed and insulated box (A) contains a radioactive source (B) which has a 50% chance during the course of the "experiment" of triggering Geiger counter (C) which activates a mechanism (D) causing a hammer to smash a flask of prussic acid (E) and killing the cat (F).
An observer (G) must open the box in order to collapse the state vector of the system into one of the two possible states. A second observer (H) may be needed to collapse the state vector of the larger system containing the first observer (G) and the apparatus (A-F). And so on ...

7. Paradox? What Paradox!?
(1.) The State of the Cat is “Entangled” with That of the Atom.
(2.) The Cat is in a Simultaneous Superposition of Dead & Alive.
(3.) Observers are Required to “Collapse” the Cat to Dead or Alive

8. Quantum Entanglement
“Quantum entanglement is the characteristic trait of quantum mechanics, the one that enforces its entire departure from classical lines of thought.”
— Erwin Schrödinger

9. Conservation of Classical Angular MomentumB A

10. Conservation of Quantum Spin
David Bohm B A
Entangled

11. Einstein, Podolsky, Rosen (EPR) Paradox
Albert Einstein
Boris Podolsky
Nathan Rosen
“If, without in any way disturbing a system, we can predict with certainty ... the value of a physical quantity, then there exists an element of physical reality corresponding to this physical quantity."

12. + + Hidden Variable Theory A B
Can the Spooky, Action-at-a-distance Predictions (Entanglement) of Quantum Mechanics… + A B
…Be Replaced by Some Sort of Local, Statistical, Classical (Hidden Variable) Theory?

13. NO!—Bell’s Inequality
John Bell
The physical predictions of quantum theory disagree with those of any local (classical) hidden-variable theory!

14. Clauser (1978) & Aspect (1982) Experiments
Alain Aspect A B H V
Two-Photon
Atomic
Decay
John Clauser H A V B +
V= Vertical Polarization
H = Horizontal Polarization

15. Quantum Light—Over the Rainbow

16. Parametric Downconversion: Type I

17. Parametric Downconversion: Type I
Photon Pairs UV
Pump
Signal B
Idler A
Degenerate (Entangled) Case: ws=wi w s , j k A i B +

18. Parametric Downconversion: Type I

19. Parametric Downconversion: Type IIH A V B +
Degenerate (Entangled) Case: ws=wi A B

21. Tests of Bell’s Inequalities at Innsbruck
Alice
Bob
Type II Downcoversion
Anton Zeilinger

23. Teleportation Experiment at Innsbruck
EPR Source
Bell State Analysis
Experiment

24. NIST Heralded Photon Absolute Light Source
Alan Migdall
Output characteristics :
photon #  known
photon timing  known
wavelength  known
direction  known
polarization  known

25. Detector Quantum Efficiency Scheme
Detector to be Calibrated
Trigger or “Herald” Detector
No External Standards Needed!

26. Characterizing Two-Photon Entanglement
Kwiat Super-Bright Source
Any two-photon tomography requires 16 of these measurements.
Examples
Arm Arm 2
H V
H R
D D
Black Box
Generates arbitrary
Entangled States
QWP
HWP
PBS
Detector
This setup allows measurement of an arbitrary polarization state in each arm.
Paul Kwiat U. Illinois

27. Characterization of Entangled States
Werner States

28. Bob and “Charly” Share Random Crypto Key Nicolas Gisin
Quantum Cryptography at University of Geneva
Bob and “Charly” Share Random Crypto Key
System Under Lake Geneva
Nicolas Gisin

29. New York Times

30. The Hong-Ou-Mandel Effect
Leonard Mandel

31. Quantum Optical Lithography
Quantum Peak
Is Narrower and
Spacing is HALVED!
Classical One-Photon Absorption —
Classical Two-Photon Absorption —
Quantum Two-Photon Absorption —

32. Hans Bachor Displacement Measurements and Gravity Waves
squeezed vacuum : OPA
+ 0.92
0.08
coherent beam
wave plate
R=0.92
33cm
lens f=3cm
3.3cm
Image of the wave plate plane with waist=300m
Hans Bachor
Australian National University

33. Quantum Clock Synchronization
Entangled Photons Can Synchronize Past the Turbulent Atmosphere!
Seth
Lloyd
MIT A B

34. Quantum Computing
Entangled Photons are a Resource for Scalable Quantum Computation!
E. Knill, R. Laflamme and G. Milburn, Nature 409, 46, (2001)
Quantum Controlled-NOT Gate using and Entangled-Light Source, Beam Splitters, and Detectors.
Gerard
Milburn
University Of
Queensland