Quantum Retrocausality for Two-year-olds Huw Price Centre for Time - PowerPoint PPT Presentation

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion Quantum Retrocausality for Two-year-olds Huw Price Centre for Time · University of Sydney Huw Price Quantum Retrocausality for Two-year-olds 1/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion The classical case (right) L = 0 R = 0 Photon Beam L = 1 R = 1 τ L τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R Malus’ Law: Intensity R =1 = cos 2 ( τ R − σ R ), Intensity R =0 = sin 2 ( τ R − σ R ) Huw Price Quantum Retrocausality for Two-year-olds 2/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion The classical case (right) L = 0 R = 0 Photon Beam L = 1 R = 1 τ L τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R Malus’ Law: Intensity R =1 = cos 2 ( τ R − σ R ), Intensity R =0 = sin 2 ( τ R − σ R ) Huw Price Quantum Retrocausality for Two-year-olds 2/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion The classical case (right) L = 0 R = 0 Photon Beam L = 1 R = 1 τ L τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R Malus’ Law: Intensity R =1 = cos 2 ( τ R − σ R ), Intensity R =0 = sin 2 ( τ R − σ R ) Huw Price Quantum Retrocausality for Two-year-olds 2/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion The classical case (left) L = 0 R = 0 Beam Photon L = 1 R = 1 τ L τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R ‘T-reversed’: Intensity L =1 = cos 2 ( τ L − σ L ), Intensity L =0 = sin 2 ( τ L − σ L ) Huw Price Quantum Retrocausality for Two-year-olds 3/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion The classical case (left) L = 0 R = 0 Beam Photon L = 1 R = 1 τ L τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R ‘T-reversed’: Intensity L =1 = cos 2 ( τ L − σ L ), Intensity L =0 = sin 2 ( τ L − σ L ) Huw Price Quantum Retrocausality for Two-year-olds 3/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion The classical case (left) L = 0 R = 0 Beam Photon L = 1 R = 1 τ L τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R ‘T-reversed’: Intensity L =1 = cos 2 ( τ L − σ L ), Intensity L =0 = sin 2 ( τ L − σ L ) Huw Price Quantum Retrocausality for Two-year-olds 3/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion Thinking about connection and control L = 0 R = 0 Beam L = 1 R = 1 τ = τ L = τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R Polarization as a mechanism 1 What we can wiggle 2 Huw Price Quantum Retrocausality for Two-year-olds 4/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion Thinking about connection and control L = 0 R = 0 Beam L = 1 R = 1 τ = τ L = τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R Polarization as a mechanism 1 What we can wiggle 2 Huw Price Quantum Retrocausality for Two-year-olds 4/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion Thinking about connection and control L = 0 R = 0 Beam L = 1 R = 1 τ = τ L = τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R Polarization as a mechanism 1 What we can wiggle 2 Huw Price Quantum Retrocausality for Two-year-olds 4/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion Defeating the demons of the left? L = 0 R = 0 Beam L = 1 R = 1 τ = τ L = τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R Suppose you control the left polarizer, σ L , but not the input beams – the Demon of the Left controls those. Can you control the polarization of the output beam, τ ? No! The Demon can make τ whatever She likes, by choosing the appropriate input intensities. (The Demon can “counteract” your wiggles, in other words.) Huw Price Quantum Retrocausality for Two-year-olds 5/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion Defeating the demons of the left? L = 0 R = 0 Beam L = 1 R = 1 τ = τ L = τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R Suppose you control the left polarizer, σ L , but not the input beams – the Demon of the Left controls those. Can you control the polarization of the output beam, τ ? No! The Demon can make τ whatever She likes, by choosing the appropriate input intensities. (The Demon can “counteract” your wiggles, in other words.) Huw Price Quantum Retrocausality for Two-year-olds 5/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion Defeating the demons of the left? L = 0 R = 0 Beam L = 1 R = 1 τ = τ L = τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R Suppose you control the left polarizer, σ L , but not the input beams – the Demon of the Left controls those. Can you control the polarization of the output beam, τ ? No! The Demon can make τ whatever She likes, by choosing the appropriate input intensities. (The Demon can “counteract” your wiggles, in other words.) Huw Price Quantum Retrocausality for Two-year-olds 5/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion Defeating the demons of the left? L = 0 R = 0 Beam L = 1 R = 1 τ = τ L = τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R Suppose you control the left polarizer, σ L , but not the input beams – the Demon of the Left controls those. Can you control the polarization of the output beam, τ ? No! The Demon can make τ whatever She likes, by choosing the appropriate input intensities. (The Demon can “counteract” your wiggles, in other words.) Huw Price Quantum Retrocausality for Two-year-olds 5/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion Defeating the demons of the left? L = 0 R = 0 Beam L = 1 R = 1 τ = τ L = τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R Suppose you control the left polarizer, σ L , but not the input beams – the Demon of the Left controls those. Can you control the polarization of the output beam, τ ? No! The Demon can make τ whatever She likes, by choosing the appropriate input intensities. (The Demon can “counteract” your wiggles, in other words.) Huw Price Quantum Retrocausality for Two-year-olds 5/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion Defeating the demons of the left? L = 0 R = 0 Beam L = 1 R = 1 τ = τ L = τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R Suppose you control the left polarizer, σ L , but not the input beams – the Demon of the Left controls those. Can you control the polarization of the output beam, τ ? No! The Demon can make τ whatever She likes, by choosing the appropriate input intensities. (The Demon can “counteract” your wiggles, in other words.) Huw Price Quantum Retrocausality for Two-year-olds 5/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion Defeating the demons of the left? L = 0 R = 0 Beam L = 1 R = 1 τ = τ L = τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R Suppose you control the left polarizer, σ L , but not the input beams – the Demon of the Left controls those. Can you control the polarization of the output beam, τ ? No! The Demon can make τ whatever She likes, by choosing the appropriate input intensities. (The Demon can “counteract” your wiggles, in other words.) Huw Price Quantum Retrocausality for Two-year-olds 5/14

Classical Polarization 101 Playing with blocks Quantum Polarization 101 Playing with quantum blocks Caveats Conclusion Defeating the demons of the left? L = 0 R = 0 Beam L = 1 R = 1 τ = τ L = τ R Polarizing cube Polarizing cube set at angle σ L set at angle σ R Suppose you control the left polarizer, σ L , but not the input beams – the Demon of the Left controls those. Can you control the polarization of the output beam, τ ? No! The Demon can make τ whatever She likes, by choosing the appropriate input intensities. (The Demon can “counteract” your wiggles, in other words.) Huw Price Quantum Retrocausality for Two-year-olds 5/14