560 likes | 712 Views
Sharpening Occam ’s razor with Quantum Mechanics. SISSA Journal Club. Matteo Marcuzzi. 8th April , 2011. Describing Systems. Clausius Ptolemaeus ( Ptolemy ). Niclas Koppernigck ( Copernicus ). Tyge Brahe ( Tychonis ). Describing Systems. Johannes Kepler. Describing Systems.
E N D
SharpeningOccam’s razorwith Quantum Mechanics SISSA Journal Club Matteo Marcuzzi 8th April, 2011
DescribingSystems ClausiusPtolemaeus (Ptolemy) NiclasKoppernigck (Copernicus) TygeBrahe (Tychonis)
DescribingSystems Johannes Kepler
DescribingSystems AlgorithmicAbstraction
DescribingSystems AlgorithmicAbstraction Same output
DescribingSystems Solar system celestialobjects SunFlares PlanetOrography Meteorology People behaviour Compton Scattering Same output Differentintrinsic information!
DescribingSystems Much more memoryrequired! OCCAM’S RAZOR Same output Differentintrinsic information!
DescribingSystems N SpinChain ifeven Up parity ifodd 1spin-flip per second 0
DescribingSystems N SpinChain ifeven Up parity ifodd 1spin-flip per second 0 1
DescribingSystems N SpinChain ifeven Up parity ifodd 1spin-flip per second 0 1 0
DescribingSystems N SpinChain ifeven Up parity ifodd 1spin-flip per second 0 1 0 1
DescribingSystems N SpinChain ifeven Up parity ifodd 1spin-flip per second 0 1 0 1 0
DescribingSystems N SpinChain ifeven Up parity ifodd 1spin-flip per second 0 1 0 1 0 1
DescribingSystems N SpinChain ifeven Up parity ifodd 1spin-flip per second 0 1 0 1 0 1 0
DescribingSystems N SpinChain ifeven Up parity ifodd 1spin-flip per second 0 1 0 1 0 1 0 1
DescribingSystems N SpinChain ifeven Up parity ifodd 1spin-flip per second N bitsneeded 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
DescribingSystems Hidden System N bits read x 1-bit only! return (x+1) mod 2 Statisticallyequivalent output 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
ComputationalMechanics • Statisticalequivalence • Measureofcomplexity • Pattern identification
ComputationalMechanics • Statisticalequivalence • Measureofcomplexity • Pattern identification
ComputationalMechanics • Statisticalequivalence • Measureofcomplexity • Pattern identification
ComputationalMechanics • Statisticalequivalence • Measureofcomplexity • Pattern identification ?
ComputationalMechanics StochasticProcess Discrete Stationary Alphabet RandomVariables
ComputationalMechanics StochasticProcess Discrete Stationary Alphabet RandomVariables Pasts Futures
ComputationalMechanics StochasticProcess Discrete Stationary Alphabet RandomVariables Set ofhistories Set of future strings
ComputationalMechanics StochasticProcess Discrete Stationary 000101000101110101101… Machine StatisticalEquivalence
ComputationalMechanics StochasticProcess Discrete Stationary PartitionR …010100010 …01010101 Machine States …1100111
ComputationalMechanics StochasticProcess Discrete Stationary PartitionR Machine States
ComputationalMechanics StochasticProcess Discrete Stationary Rj Ri a Machine TransitionRates
ComputationalMechanics StochasticProcess Discrete Stationary OCCAM POOL
ComputationalMechanics A little information theory Shannonentropy Conditionalentropy Mutual information Excessentropy
ComputationalMechanics PartitionR Wewanttopreserve information Machine Cannotdistinguishbetweenthem
ComputationalMechanics PartitionR minimize Log(# states) Wewanttopreserve information Machine with the leastpossiblememory
ComputationalMechanics PartitionR Statistical complexity minimize Wewanttopreserve information Machine with the leastpossiblememory
ComputationalMechanics OCCAM POOL Optimalpartition Statistical complexity minimize Wewanttopreserve information with the leastpossiblememory
ComputationalMechanics Optimalpartition if CausalStates ε Statistical complexity minimize Wewanttopreserve information ε-machine with the leastpossiblememory (unique)
ComputationalMechanics: Examples 2-periodic sequence 2-periodic, endswith A initial state I B 2-periodic, endswith
ComputationalMechanics: Examples 2-periodic sequence A initial state I transient recurrent B
ComputationalMechanics: Examples 1D Isingmodel transfer matrix
ComputationalMechanics: Examples 1D Next-nearest-neighboursIsing 2
ComputationalMechanics: Examples 1D Next-nearest-neighboursIsing 3 2
ComputationalMechanics: Examples 1D Next-nearest-neighboursIsing 3 2 1
ComputationalMechanics: Examples 1D Next-nearest-neighboursIsing 3 2 1
ComputationalMechanics: Examples 1D Next-nearest-neighboursIsing negligible
ComputationalMechanics: Examples 1D Next-nearest-neighboursIsing period3 period1
Sharpening the razorwith QM Statisticalcomplexity Excessentropy Ideal system
Sharpening the razorwith QM ε ε ε-machines are deterministic
Sharpening the razorwith QM ε fixed i,c unique j fixed j,c unique i ideal
Sharpening the razorwith QM qε ε causal state Ri system state symbol “s” symbol state q-machinestates