schrödinger’s rainbow: the renaissance in quantum optical interferometry
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Schrödinger’s Rainbow: The Renaissance in Quantum Optical Interferometry. Jonathan P. Dowling Quantum Science & Technologies ( Q S T ) Group Hearne Institute for Theoretical Physics Louisiana State University. http://quantum.phys.lsu.edu. Table of Contents. • Quantum Technologies - PowerPoint PPT PresentationTRANSCRIPT
Schrödinger’s Rainbow: The Renaissance in Quantum Optical Interferometry
Jonathan P. DowlingQuantum Science & Technologies (QST) Group
Hearne Institute for Theoretical PhysicsLouisiana State University
http://quantum.phys.lsu.edu
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
Quantum Technology: The Second Quantum RevolutionJP Dowling & GJ Milburn, Phil. Transactions of the Royal Soc. of London
QuantumMechanical
Systems
PendulumsCantileversPhonons
CoherentQuantumElectronics
SuperconductorsExcitonsSpintronics
Quantum Optics
Ion TrapsCavity QEDLinear Optics
QuantumAtomics
Bose-EinsteinAtomic CoherenceIon TrapsQuantum
InformationProcessing
Schrödinger’s Cat and All That
Schrödinger’s Cat Revisited
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 ...
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
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
Conservation of Classical Angular
Momentum
A B
Conservation of Quantum Spin
Entangled
David Bohm
A B
Einstein, Podolsky, Rosen (EPR) Paradox
Albert Einstein
Boris Podolsky
“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."
Nathan Rosen
Hidden Variable Theory
+A B A B
Can the Spooky, Action-at-a-distance Predictions (Entanglement) of Quantum Mechanics…
+A B A B
…Be Replaced by Some Sort of Local, Statistical, Classical (Hidden Variable) Theory?
NO!—Bell’s Inequality
The physical predictions of quantum theory disagree with those of any local (classical) hidden-variable theory!
John Bell
Clauser (1978) & Aspect (1982) Experiments
John Clauser
Alain Aspect
V= Vertical Polarization
H = Horizontal Polarization
HAV
B VAH
B
A B
H
V H
VTwo-PhotonAtomicDecay
Quantum Light—Over the Rainbow
Parametric Downconversion: Type I
Parametric Downconversion: Type I
UV
Pump
Signal B
Idler A
Degenerate (Entangled) Case: s=iDegenerate (Entangled) Case: s=i
s, s, ks A i, i, ks B i, i, ki A s, s, ks B
Type I
Photon Pairs
Parametric Downconversion: Type I
QuickTime™ and aSorenson Video decompressorare needed to see this picture.
A
B
Parametric Downconversion: Type II
HAV
B VAH
B
Degenerate (Entangled) Case: s=iDegenerate (Entangled) Case: s=i
QuickTime™ and aAnimation decompressor
are needed to see this picture.
Putting Entangled Light to Work
Tests of Bell’s Inequalities at Innsbruck
Anton ZeilingerAlice
Bob
Type II Downcoversion
Quantum Teleportation
Teleportation Experiment at Innsbruck
Bell State Analysis
EPR Source
Experiment
NIST Heralded Photon Absolute Light Source
Output characteristics : photon # knownphoton timing knownwavelength knowndirection knownpolarization known Alan Migdall
0
ω2
ω1
PARAMETRIC CRYSTAL
COUNTER
COINC COUNTER
AbsoluteQuantumEfficiency
COUNTER
N
Detector to be Calibrated
Trigger or “Herald” DetectorN1=η1N N2=η2N NC=η1η2N
η1=NC/ N2
Detector Quantum Efficiency Scheme
No External Standards Needed!No External Standards Needed!
Black BoxGenerates arbitrary Entangled States
QWP
QWP
HWP
HWP
PBS
PBS
Detector
Detector
This setup allows measurement of an arbitrary polarization
state in each arm.
Any two-photon tomography requires 16 of these measurements.
ExamplesArm 1 Arm 2 H V H R D D
Characterizing Two-Photon Entanglement
Paul KwiatU. Illinois
#1
H-polarized(from #1)Type-I phase-matching
#2V-polarized(from #2)
#1
H-polarized(from #1)Type-I phase-matching
Kwiat Super-Bright Source
0
0.2
0.4
0.6
0.8
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 1
Maximally-Entangled Mixed States
0
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 10
0.2
0.4
0.6
0.8
1
0 0.2 0.4 0.6 0.8 1
Linear entropy, SLPure
states
Product States
Bell StatesImpossible States
Mixed states
Characterization of Entangled States
Werner States
Bob and “Charly” Share Random Crypto Key
Quantum Cryptography at University of Geneva
System Under Lake Geneva
Nicolas Gisin
New York Times
The Hong-Ou-Mandel Effect
Leonard Mandel
EASY (BUT USELESS?) FOR N=2ABA′B′CBSMMPS - Two Photon Absorption
1
A1
B
0A
2B
+ e2 i ϕ
2A
0B
2
Parametric Downcoversion
Classical One-Photon Absorption —Classical Two-Photon Absorption —Quantum Two-Photon Absorption —
- p 0 pj
0.5
1
1.5
2D
Quantum PeakIs Narrower andSpacing is HALVED!
Quantum PeakIs Narrower andSpacing is HALVED!
Quantum Optical Lithography
squeezed vacuum : OPA
+ 0.920.08
coherent beam
wave plate
R=0.92
33cm
lens f=3cm
3.3cm
Image of the wave plate plane with
waist=300m
Displacement Measurements and Gravity Waves
Hans BachorAustralian National University
Δxclassical=λ, Δxshotnoise=λN
, ΔxHeisenberg=λN
Quantum Clock Synchronization
Entangled Photons Can Synchronize Past the Turbulent Atmosphere!Entangled Photons Can Synchronize Past the Turbulent Atmosphere!
SethLloydMIT
A B
Quantum Computing
Quantum Controlled-NOT Gate using and Entangled-Light Source, Beam Splitters, and Detectors.
Entangled Photons are a Resource for Scalable Quantum Computation!Entangled Photons are a Resource for Scalable Quantum Computation!
E. Knill, R. Laflamme and G. Milburn, Nature 409, 46, (2001)
E. Knill, R. Laflamme and G. Milburn, Nature 409, 46, (2001)
GerardMilburnUniversityOfQueensland
Computing
CommunicationsClock SynchronizationImaging
SensorsMetrology
The Yellow-Brick Roadmap