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Constructor Theory of Information
by David Deutsch & Chiara Marletto (2014)
https://arxiv.org/pdf/1405.5563.pdf
#InformationIsPhysical #ConstructorTheory
by David Deutsch & Chiara Marletto (2014)
https://arxiv.org/pdf/1405.5563.pdf
#InformationIsPhysical #ConstructorTheory
'All these applications of information involve abstraction, in that one entity is represented symbolically by another. But information is not abstract in the same sense as, say, the set of all prime numbers, for it only exists when it is physically instantiated.‘
'So the laws governing it, like those governing computation – but unlike those governing prime numbers – are laws of physics. In this paper we conjecture what these laws are.'
'Also, despite being physical, information has a counter-factual character: an object in a particular physical state cannot be said to carry information unless it could have been in a different state.'
A great analysis of information as a physical quantity is provided by Neal Anderson.
A key insight: to untangle the situation, a separation of system and environment is not enough.
The observer M of system A that has information about R is necessarily part of the setup.
A key insight: to untangle the situation, a separation of system and environment is not enough.
The observer M of system A that has information about R is necessarily part of the setup.
Anderson defines a number of criteria for (classical) information as a physical quantity in quantum mechanical systems, of which classical systems are a special case.
The measure he creatures, fulfilling the criteria, is called 'observer-local referential information' (OLR inf.).
The measure he creatures, fulfilling the criteria, is called 'observer-local referential information' (OLR inf.).
The definition of OLR information is based on (the physical measures) von Neumann entropy and quantum mutual information.
OLR information is understood to be „information about sth,“ = referential.
Let me briefly explain the idea in the next tweet.
(see graphic 2 tweets above)
OLR information is understood to be „information about sth,“ = referential.
Let me briefly explain the idea in the next tweet.
(see graphic 2 tweets above)
The observed system A has information about the referent system R.
OLR information is non-zero onlyif observer M can observe the systems R, too. If R and A are observable, OLR is quantum mutual information in the general case and mutual information I(R;A) in the classical case.
OLR information is non-zero onlyif observer M can observe the systems R, too. If R and A are observable, OLR is quantum mutual information in the general case and mutual information I(R;A) in the classical case.
It is physically meaningless for an observer M to say that A has information about R at time t, when R and A are not inside the observer domain O at time t.
O is the boundary for information as physical quantity AND inherently observer-dependent measure.
/HT @GaneshNatesh
O is the boundary for information as physical quantity AND inherently observer-dependent measure.
/HT @GaneshNatesh
Observation is a form of correlation, too:
Information is transferred from A to O, which according to Bekenstein (1981) has a certain energy cost: "Every message is associated with a material object or radiation , and must thus be accompanied by some energy."
Information is transferred from A to O, which according to Bekenstein (1981) has a certain energy cost: "Every message is associated with a material object or radiation , and must thus be accompanied by some energy."
A few years ago the type of correlation has been clarified.
"No energy transport without discord" (1510.05035).
Discord is an asymmetric quantum correlation (no entanglement) that is the min. difference btw. quantum mutual information & mutual information for local measurements.
"No energy transport without discord" (1510.05035).
Discord is an asymmetric quantum correlation (no entanglement) that is the min. difference btw. quantum mutual information & mutual information for local measurements.
Now how do discord between A/O and R/O relate to OLR information that connects A and R?
Physical information is a triangular relationship.
