Contents
1	Introduction	3
	1.1      Core Quantum Postulates.........................................................................................................................................................................................	3
	1.2      Quantum States, Information, and Existence.........................................................................................................................................................	5
	1.3      Interpreting Relative States Interpretation.............................................................................................................................................................	7
	1.4      Preview.......................................................................................................................................................................................................................	9
2	Quantum Jumps and Einselection from Information Flows and Predictability	10
	2.1      Repeatability and the Quantum Origin of Quantum Jumps..................................................................................................................................	11
	2.2      Mixed States of the “Target”......................................................................................................................................................................................	13
	2.3      Predictability Killed the (Schrödinger’s) Cat...........................................................................................................................................................	15
	2.4      Records and Branches: Degenerate “Control”.........................................................................................................................................................	15
	Repeatability and Actionable Information................................................................................................................................................	17
	2.5      Pointer Basis, Information Transfer, and Decoherence..........................................................................................................................................	19
	2.6      Irreversibility of Perceived Events, or “Don’t Blame the 2nd Law—Wavepacket Collapse Is Your Own Fault!”...........................................	21
	2.6.1      Classical Measurement Can Be Reversed Even when Record of the Outcome is Kept.......................................................................	21
	2.6.2      Quantum Measurement Can’t Be Reversed when the Record of the Outcome is Kept......................................................................	22
	2.7      Summary: Events, Irreversibility, and Perceptions................................................................................................................................................	23
3	Born’s Rule from the Symmetries of Entanglement	24
	3.1      Envariance...................................................................................................................................................................................................................	26
	3.2      Decoherence as a Result of Envariance....................................................................................................................................................................	27
	3.3      Swaps, Counterswaps, and Equiprobability............................................................................................................................................................	28
	3.4      Born’s Rule from Envariance.....................................................................................................................................................................................	31
	3.4.1      Additivity of Probabilities from Envariance.............................................................................................................................................	33
	3.4.2      Algebra of Records as the Boolean Algebra of Events.............................................................................................................................	35
	3.5      Inverting Born’s Rule: Why Is the Amplitude a Square Root of the Frequency of Occurrence?.......................................................................	36
	3.6      Relative Frequencies from Relative States...............................................................................................................................................................	39
	3.7      Envariance—An Overview........................................................................................................................................................................................	41
	3.7.1      Implications and the Scope of Envariance: Why Entanglement? Why Schmidt States?......................................................................	41
	3.7.2      Towards the Experimental Verification of Envariance............................................................................................................................	43
4	Quantum Darwinism	45
	4.1      Mutual Information, Redundancy, and Discord.....................................................................................................................................................	48
	4.1.1      Mutual Information.....................................................................................................................................................................................	48
	4.1.2      Quantum Discord........................................................................................................................................................................................	50
	4.1.3      Evidence and Its Redundancy....................................................................................................................................................................	52
	4.1.4      Mutual Information, Pure Decoherence, and Branching States.............................................................................................................	54
	4.1.5      Surplus Decoherence and Redundant Decoherence................................................................................................................................	56
	4.1.6      Information Gained by Pure and Mixed Environments..........................................................................................................................	57
	4.1.7      Environment as a Communication Channel.............................................................................................................................................	58
	4.1.8      Quantum Darwinism and Amplification Channels.................................................................................................................................	59
	4.2      Quantum Darwinism in Action.................................................................................................................................................................................	59
	4.2.1       C-Nots and Qubits......................................................................................................................................................................................	60
	4.2.2      Central Spin Decohered by Noninteracting Spins....................................................................................................................................	61
	4.2.3      Quantum Darwinism in a Hazy Environment..........................................................................................................................................	64
	4.2.4      Quantum Darwinism and Pointer States...................................................................................................................................................	65
	4.2.5      Redundancy vs. Relaxation in the Central Spin Model...........................................................................................................................	68
	4.2.6      Quantum Darwinism in Quantum Brownian Motion.............................................................................................................................	71
	4.2.7      Huge Redundancy in Scattered Photons..................................................................................................................................................	74
	4.3      Experimental Tests of Quantum Darwinism...........................................................................................................................................................	78
	4.4      Summary: Environment as an Amplification Channel...........................................................................................................................................	80
5	Quantum Darwinism and Objective Existence: Photohalos and Extantons	82
	5.1      Anatomy of an Extanton............................................................................................................................................................................................	82
	5.1.1      Extantons and “The Classical”...................................................................................................................................................................	83
	5.1.2      Photohalos, Photoextantons, and Information Detached from Existence.............................................................................................	84
	5.1.3      Photohalos and the Quantum Origins of Irreversibility.........................................................................................................................	85
	5.2      Quantum Darwinism and the Existential Interpretation.......................................................................................................................................	85
	5.3      From Quantum Core Postulates to Objective Classical Reality.............................................................................................................................	86
	5.4      Extantons and the Existential Interpretation..........................................................................................................................................................	87
	5.5      Decoherence and Information Processing...............................................................................................................................................................	88
	5.6      Quantum Darwinism and “Life as We Know It”....................................................................................................................................................	89
	Seeing Is Believing......................................................................................................................................................................................	90
	5.7      Bohr, Everett, and Wheeler........................................................................................................................................................................................	90
	5.8      Closing Remarks.........................................................................................................................................................................................................	92
References		94